Huawei UMTS Parameter Most Important

WCDMA UE Behaviors in Idle Mode www.huawei.com

Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

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Foreword z

UE behaviors in idle mode include :

PLMN selection

System information reception

Cell selection and reselection

Location registration

Paging procedure

Access procedure


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PLMN selection Used to ensure that the PLMN selected by the UE properly provides services.

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Cell selection and reselection Used to ensure that the UE finds a suitable cell to camp on.

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Location registration Used for the network to trace the current status of the UE and to ensure that the UE is camped on the network when the UE does not perform any operation for a long period.

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System information reception The network broadcasts the network information to a UE which camps on the cell to control the behaviors of the UE.

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Paging Used for the network to send paging messages to a UE which is in idle mode, CELL_PCH state, or URA_PCH state.

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Access From the view of access stratum, access is the procedure UE shift from idle mode to connected mode.

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Contents 1. PLMN Selection 2. System Information Reception 3. Cell Selection and Reselection 4. Location Registration 5. Paging Procedure 6. Access Procedure


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Cell Search z

UE does not have UTRAN carrier information

In order to find a suitable cell to stay, UE will scan all the frequencies in UTRAN. In each carrier, UE just need to find a cell with best signal

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UE has UTRAN carrier information

UE will try whether the original cell is suitable to stay. If not, UE still need to scan all the frequencies about UTRAN in order to find a suitable cell in PLMN


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Typical scenario of first occasion is the first time a new UE is put into use.

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The second occasion is very common.

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Cell Search Slot synchronization

Frame synchronization and code-group identification

Primary Scrambling code identification


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Step 1: Slot synchronization During the first step of the cell search procedure the UE uses the primary synchronisation code (PSC) to acquire slot synchronisation to a cell.

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Step 2: Frame synchronization and code-group identification During the second step of the cell search procedure, the UE uses the secondary synchronisation code (SSC) to find frame synchronisation and identify the code group of the cell found in the first step.

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Step 3: Primary Scrambling code identification: During the last step of the cell search procedure, the UE determines the exact primary scrambling code used by the found cell. The primary scrambling code is typically identified through symbol-by-symbol correlation over the CPICH with all codes within the code group identified in the second step.

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If the UE has received information about which scrambling codes to search for, steps 2 and 3 above can be simplified.

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PLMN Selection z

UE shall maintain a list of allowed PLMN types. In the PLMN list, the UE arranges available PLMNs by priorities. When selecting a PLMN, it searches the PLMNs from the high priority to the low.

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The UE selects a PLMN from HPLMNs or VPLMNs.


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UE can get the system information from PCCPCH, and the PLMN information is transmitted in MIB of PCCPCH After getting the MIB, UE can judge weather the current PLMN is the right one. If so, UE will get the SIB scheduling information from the MIB; if not, UE will search another carrier, do this procedure again

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PLMN Selection (Cont.) z

PLMN Selection in HPLMNs

Automatic PLMN Selection Mode

The UE selects an available and suitable PLMN from the whole band according to the priority order

Manual PLMN Selection Mode

The order of manual selection is the same as that of automatic selection.


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The priority order for automatic PLMN selection mode Order

PLMN type

Remark

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HPLMNs

Home PLMNs

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PLMNs contained in the "User Controlled PLMN Selector with Access Technology" data field in the SIM excluding the previously selected PLMN

The PLMNs are arranged in priority order

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PLMNs contained in the "Operator Controlled PLMN Selector with Access Technology" data field in the SIM excluding the previously selected PLMN

The PLMNs are arranged in priority order

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Other PLMN/access technology combinations with the high quality of received signals excluding the previously selected PLMN

The PLMNs are arranged in random order

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Other PLMN/access technology combinations excluding the previously selected PLMN

The PLMNs are arranged in descending order of signal quality.

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Previously selected PLMN

The PLMN selected by the UE before automatic PLMN selection

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PLMN Selection (Cont.) z

PLMN Selection in VPLMNs

If a UE is in a VPLMN, it scans the “user controlled PLMN selector” field or the “operator controlled PLMN selector” field in the PLMN list to find the HPLMN or the PLMN with higher priority according to the requirement of the automatic PLMN selection mode.


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A value of T minutes may be stored in the SIM. T is either in the range from 6 minutes to 8 hours in 6-minute steps or it indicates that no periodic attempts shall be made. If no value is stored in the SIM, a default value of 60 minutes is used. After the UE is switched on, a period of at least 2 minutes and at most T minutes shall elapse before the first attempt is made. The UE shall make an attempt if the UE is on the VPLMN at time T after the last attempt.

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Structure of System Information z

System information is organized as a tree, including:

MIB (Master Information Block )

SB (Scheduling Block )

SIB (System Information Block )


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System information is used for the network to broadcast network information to UEs camping on a cell so as to control the behavior of UEs. MIB

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Scheduling Block (SB) gives reference and scheduling information to other SIBs. The scheduling information of a SIB may be included in only one of MIB and SB.

SIB

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When selecting a new cell, the UE reads the MIB. The UE may locate the MIB by predefined scheduling information. The IEs in the MIB includes MIB value tag, PLMN type, PLMN identity, reference and scheduling information for a number of SIBs in a cell or one or two SBs in a cell.

SB

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System Information Block (SIB) contains actual system information. It consists of system information elements (IEs) with the same purpose.

Scheduling information for a system information block may only be included in either the master information block or one of the scheduling blocks.

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System Information z

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SIB1: Contains the system information for NAS and the timer/counter for UE SIB2: Contains the URA information SIB3: Contains the parameters for cell selection and cell reselection SIB5: Contains parameters for the common physical channels of the cell SIB7: Contains the uplink interference level and the refreshing timer for SIB7 SIB11: Contains measurement controlling information


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SIB4: Contains parameters for cell selection and cell re-selection while UE is in connected mode SIB6: Contains parameters for the common physical channels of the cell while UE is in connected mode

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SIB8: Contains the CPCH static information

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SIB9: Contains the CPCH dynamic information

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SIB10: Contains information to be used by UEs having their DCH controlled by a DRAC procedure. Used in FDD mode only. To be used in CELL_DCH state only. Changes so often, its decoding is controlled by a timer

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SIB12: Contains measurement controlling information in connecting mode

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SIB13: Contains ANSI-41 system information

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SIB14: Contains the information in TDD mode

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SIB15: Contains the position service information

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SIB16: Contains the needed pre-configuration information for handover from other RAT to UTRAN

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SIB17: Contains the configuration information for TDD

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SIB18: Contains the PLMN identities of the neighboring cells

To be used in shared networks to help with the cell reselection process

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Reception of System Information z

The UE shall read system information broadcast on a BCH transport channel when the UE is in idle mode or in connected mode, that is, in CELL_FACH, CELL_PCH, or URA_PCH state.


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The UE may use the scheduling information in MIB and SB to locate each SIB to be acquired. If the UE receives a SIB in a position according to the scheduling information and consider the content valid, it will read and store it.

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Cell Selection z

When the PLMN is selected and the UE is in idle mode, the UE starts to select a cell to camp on and to obtain services.

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There are four states involved in cell selection:

Camped normally

Any cell selection

Camped on any cell

Connected mode


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Camped normally: The cell that UE camps on is called the suitable cell. In this state, the UE obtains normal service. Any cell selection: In this state, the UE shall attempt to find an acceptable cell of an any PLMN to camp on, trying all RATs that are supported by the UE and searching first for a high quality cell Camped on any cell: The cell that UE camps on is called the acceptable cell. In this state the UE obtains limited service. The UE shall regularly attempt to find a suitable cell of the selected PLMN, trying all RATs that are supported by the UE. Connected mode: When returning to idle mode, the UE shall use the procedure Cell selection when leaving connected mode in order to find a suitable cell to camp on and enter state Camped normally. If no suitable cell is found in cell reselection evaluation process, the UE enters the state Any cell selection.

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Cell Selection (Cont.) z

Two types of cell selection:

Initial cell selection

If no cell information is stored for the PLMN, the UE starts this procedure.

Stored information cell selection

If cell information is stored for the PLMN, the UE starts this procedure.


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Initial cell selection: If no cell information is stored for the PLMN, the UE starts the initial cell selection. For this procedure, the UE need not know in advance which Radio Frequency (RF) channels are UTRA bearers. The UE scans all RF channels in the UTRA band according to its capabilities to find a suitable cell of the selected PLMN. On each carrier, the UE need only search for the strongest cell. Once a suitable cell is found, this cell shall be selected. Stored information cell selection: For this procedure, the UE need know the central frequency information and other optional cell parameters that are obtained from the measurement control information received before, such as scrambling codes. After this procedure is started, the UE selects a suitable cell if it finds one. Otherwise, the "Initial cell selection" procedure is triggered.

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Cell Selection Criteria z

Criterion S is used by the UE to judge whether the cell is suitable to camped on.

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Criterion S : Srxlev > 0 & Squal > 0, where:

S qual = Qqualmeas − Qqual min

S rxlev = Qrxlevmeas − Qrxlev min − Pcompensation


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If the pilot strength and quality of one cell meet S criteria, UE will stay in this cell and get other system information. Then, UE will initiate a location update registration process. If the cell doesn’t satisfy S criteria, UE will get adjacent cells information from SIB11. Then, UE will judge weather these cells satisfy S criteria. If the adjacent cell is suitable, UE will stay in the adjacent cell. If no cell satisfies S criteria, UE will take the area as dead zone and continue the PLMN selection and reselection procedure. Parameters

Explanation

Squal

Cell quality value (dB)

Srxlev

Cell RX level value (dBm)

Qqualmeas

Measured cell quality value. The quality of the received signal expressed in CPICH Ec/N0 (dB) for current cell

Qrxlevmeas

Measured cell RX level value. This is received signal, CPICH RSCP for current cells (dBm)

Qqualmin

Minimum required quality level in the cell (dB)

Qrxlevmin

Minimum required RX level in the cell (dBm)

Pcompensation UE_TXPWR_ MAX_RACH P_MAX

Max（UE_TXPWR_MAX_RACH-P_MAX，0）, dBm Maximum TX power level an UE may use when accessing the cell on RACH (read in system information) (dBm) Maximum RF output power of the UE (dBm) 17

Parameters of S Criterion z

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QUALMEAS

Parameter name: Cell Se-reselection quality measure

Recommended value: CPICH_ECNO

QQUALMIN

Parameter name: Min quality level

Recommended value: -18, namely -18dB


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QUALMEAS Parameter name: Cell Sel-reselection quality measure

Value range: CPICH_ECNO(CPICH Ec/N0),CPICH_RSCP(CPICH RSCP)

Physical unit: None.

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Content: Cell selection and reselection quality measure, may be set to CPICH Ec/N0 or CPICH RSCP. Recommended value: CPICH_ECNO.

QQUALMIN Parameter name: Min quality level

Value range: -24~0

Physical value range: -24~0; step: 1

Physical unit: dB

Content: The minimum required quality level corresponding to CPICH Ec/No. The UE can camp on the cell only when the measured CPICH Ec/No is greater than the value of this parameter. Recommended value: -18 Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and modify it through MOD CELLSELRESEL.

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Parameters of S Criterion z

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QRXLEVMIN

Parameter name: Min Rx level

Recommended value: -58, namely -115dBm

MAXALLOWEDULTXPOWER

Parameter name: Max allowed UE UL TX power

Recommended value: 21, namely 21dBm


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QRXLEVMIN Parameter name: Min Rx level

Value range: -58~-13.

Physical value range: -115~-25; step: 2 (-58:-115; -57:-113; ..., -13:-25 ).

Physical unit: dBm.

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Content: The minimum required RX level corresponding to CPICH RSCP. The UE can camp on the cell only when the measured CPICH RSCP is greater than the value of this parameter. Recommended value: -58. Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and modify it through MOD CELLSELRESEL.

MAXALLOWEDULTXPOWER


Value range: -50~33

Physical value range: -50~33; step: 1

Physical unit: dBm

Content: The maximum allowed uplink transmit power of a UE in the cell, which is related to the network planning. Content: Allowed maximum power transmitted on RACH in the cell. It is related to network planning. Recommended value: -21 Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and modify it through MOD CELLSELRESEL.

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Cell Reselection z

After selecting a cell and camping on it, the UE periodically searches for a better cell according to the cell reselection criteria. If finding such a cell, the UE selects this cell to camp on.


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UE should monitor the quality of current cell and neighbor cells in order to camp on the better cell to initiate service. The better cell is the most suitable one for the UE to camp on and obtain services. The QoS of this cell is not necessarily more satisfying.

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Measurement Start Criteria (Cont.) z

Intra-frequency measurement Squal ≤ Sintrasearch ↓ Qqualmeas − Qqualmin ≤ Sintrasearch ↓ Qqualmeas ≤ Qqualmin + Sintrasearch


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Parameters of the measurement start criteria

Name

Description

Squal


Qqualmin

Minimum required quality level in the cell (dB) .

Sintrasearch

Measurement threshold for UE to trigger intra-frequency cell reselection, compared with Squal.

Sintersearch

Measurement threshold for UE to trigger inter-frequency cell reselection, compared with Squal.

SsearchRATm

Measurement threshold for UE to trigger inter-RAT cell reselection, compared with Squal.

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Inter-frequency measurement Squal ≤ Sintersearch ↓ Qqualmeas − Qqualmin ≤ Sintersearch ↓ Qqualmeas ≤ Qqualmin + Sintersearch


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Name

Description

Squal


Qqualmin


Sintrasearch


Sintersearch


SsearchRATm


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Inter-RAT measurement Squal ≤ SsearchRATm ↓ Qqualmeas − Qqualmin ≤ SsearchRATm ↓ Qqualmeas ≤ Qqualmin + SsearchRATm


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Name

Description

Squal


Qqualmin


Sintrasearch


Sintersearch


SsearchRATm


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Parameters of Measurement Start Criteria z

IDLESINTRASEARCH

Parameter name: Intra-freq cell reselection threshold for idle mode

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Recommended value: None

CONNSINTRASEARCH

Parameter name: Intra-freq cell reselection threshold for connected mode



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IDLESINTRASEARCH Parameter name: Intra-freq cell reselection threshold for idle mode

Value range: {{-16~10},{127}} .

Physical value range: -32~20; step: 2.

Physical unit: dB.

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Content: A threshold for intra-frequency cell reselection in idle mode. When the quality (CPICH Ec/No measured by UE) of the serving cell is lower than this threshold plus the [Qqualmin] of the cell, the intra-frequency cell reselection procedure will be started. Recommended value: None. Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and modify it through MOD CELLSELRESEL.

CONNSINTRASEARCH

Parameter name: Intra-freq cell reselection threshold for connected mode

Value range: {{-16~10},{127}} .


Physical unit: dB

Content: A threshold for intra-frequency cell reselection in connect mode. When the quality (CPICH Ec/No measured by UE) of the serving cell is lower than this threshold plus the [Qqualmin] of the cell, the intra-frequency cell reselection procedure will be started. Recommended value: None. Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and modify it through MOD CELLSELRESEL.

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IDLESINTERSEARCH

Parameter name: Inter-freq cell reselection threshold for idle mode

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CONNSINTERSEARCH

Parameter name: Inter-freq cell reselection threshold for connected mode



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IDLESINTERSEARCH Parameter name: Inter-freq cell reselection threshold for idle mode

Value range: {{-16~10},{127}} .


Physical unit: dB.

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Content: A threshold for inter-frequency cell reselection in idle mode. When the quality (CPICH Ec/No measured by UE) of the serving cell is lower than this threshold plus the [Qqualmin] of the cell, the inter-frequency cell reselection procedure will be started. Recommended value: None. Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and modify it through MOD CELLSELRESEL.

CONNSINTERSEARCH

Parameter name: Inter-freq cell reselection threshold for connected mode

Value range: {{-16~10},{127}} .


Physical unit: dB

Content: A threshold for inter-frequency cell reselection in connect mode. When the quality (CPICH Ec/No measured by UE) of the serving cell is lower than this threshold plus the [Qqualmin] of the cell, the inter-frequency cell reselection procedure will be started. Recommended value: None. Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and modify it through MOD CELLSELRESEL.

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SSEARCHRAT

Parameter name: Inter-RAT cell reselection threshold



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SSEARCHRAT Parameter name: Inter-RAT cell reselection threshold

Value range: {{-16~10},{127}} .


Physical unit: dB.

Content: A threshold for inter-RAT cell reselection. When the quality (CPICH Ec/No measured by UE) of the serving cell is lower than this threshold plus the [Qqualmin] of the cell, the inter-RAT cell reselection procedure will be started. Recommended value: None. Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and modify it through MOD CELLSELRESEL.

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Measurement Start Criteria Description


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The intra-frequency, inter-frequency, and inter-RAT measurement criteria are as shown in the figure. Usually, Sintrasearch > Sintersearch > SsearchRATm

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Cell Reselection Criteria z

Criterion R is used for intra-frequency, inter-frequency cells and inter-RAT cell reselection.

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The cell-ranking criterion R is defined by :

Rs = Qmeas , s + Qhysts Rn = Qmeas ,n − Qoffset s ,n


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The cells are ranked according to R criteria specified above ,deriving Qmeas,n and Qmeas,s and calculating R value. In Rs, s means serving cell. In Rn, n means neighbor cell. The offset Qoffset1s,n is used for Qoffsets,n to calculate Rn. The hysteresis Qhyst1s is used for Qhysts to calculate Rs. If a TDD or GSM cell is ranked as the best cell, the UE shall reselect that TDD or GSM cell. If an FDD cell is ranked as the best cell and the quality measure for cell selection and reselection is set to CPICH RSCP, the UE shall reselect that FDD cell. If an FDD cell is ranked as the best cell and the quality measure for cell selection and reselection is set to CPICH Ec/N0, the UE shall perform a second ranking of the FDD cells according to the R criteria specified above. In this case, however, the UE uses the measurement quantity CPICH Ec/N0 for deriving the Qmeas,n and Qmeas,s and then calculating the R values of the FDD cells. The offset Qoffset2s,n is used for Qoffsets,n to calculate Rn, the hysteresis Qhyst2s is used for Qhysts to calculate Rs.

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Hysteresis and Time Interval Quality

Qhyst,s

Qmeas,n

Rn Rs

Qoffsets,n

Qmeas,s

Treselection


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Time

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In all the previous cases, the UE can reselect a new cell only when the following conditions are met: The new cell is better ranked than the serving cell during a time interval Treselection.

More than one second has elapsed since the UE camped on the current serving cell.

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Parameters of R Criteria z

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IDLEQHYST1S

Parameter name: Hysteresis 1 for idle mode

Recommended value: 2, namely 4dB

CONNQHYST1S

Parameter name: Hysteresis 1 for connect mode

Recommended value: 2, namely 4dB


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IDLEQHYST1S Parameter name: Hysteresis 1 for idle mode

Value range: 0~20.

Physical value range: 0~40; step: 2.

Physical unit: dB.

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Content: The hysteresis value in idle mode for serving FDD cells in case the quality measurement for cell selection and reselection is set to CPICH RSCP. It is related to the slow fading feature of the area where the cell is located. The greater the slow fading variance is, the greater this parameter. Recommended value: 2. Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and modify it through MOD CELLSELRESEL.

CONNQHYST1S

Parameter name: Hysteresis 1 for connected mode

Value range: 0~20.


Physical unit: dB.

Content: The hysteresis value in connect mode for serving FDD cells in case the quality measurement for cell selection and reselection is set to CPICH RSCP. It is related to the slow fading feature of the area where the cell is located. The greater the slow fading variance is, the greater this parameter. Recommended value: 2. Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and modify it through MOD CELLSELRESEL. 30

Parameters of R Criteria (Cont.) z

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IDLEQHYST2S

Parameter name: Hysteresis 2 for idle mode

Recommended value: Qhyst1s for idle mode

CONNQHYST2S

Parameter name: Hysteresis 2 for connected mode

Recommended value: Qhyst1s for connected mode.


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IDLEQHYST2S Parameter name: Hysteresis 2 for idle mode

Value range: {{0~20},{255}} .


Physical unit: dB.

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Content: The hysteresis value in idle mode for serving FDD cells in case the quality measurement for cell selection and reselection is set to CPICH Ec/No. It is related to the slow fading feature of the area where the cell is located. The greater the slow fading variance is, the greater this parameter. It is optional. If it is not configured, [Hysteresis 1] will be adopted as the value. Recommended value: Qhyst1s for idle mode . Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and modify it through MOD CELLSELRESEL.

CONNQHYST2S Parameter name: Hysteresis 2 for connected mode

Value range: {{0~20},{255}} .


Physical unit: dB.

Content: The hysteresis value in connect mode for serving FDD cells in case the quality measurement for cell selection and reselection is set to CPICH RSCP. It is related to the slow fading feature of the area where the cell is located. The greater the slow fading variance is, the greater this parameter. Recommended value: Qhyst1s for connected mode. . Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and modify it through MOD CELLSELRESEL.

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TRESELECTIONS

Parameter name: Reselection delay time

Recommended value: 1, namely 1s.


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TRESELECTIONS Parameter name: Reselection delay time

Value range: 0~31 .


Physical unit: s.

Content: If the signal quality of a neighboring cell is better than the serving cell during the specified time of this parameter, the UE will reselect the neighboring cell. It is used to avoid ping-pong reselection between different cells. Note: The value 0 corresponds to the default value defined in the protocol. Recommended value: 1. Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and modify it through MOD CELLSELRESEL.

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IDLEQOFFSET1SN

Parameter name: IdleQoffset1sn

Recommended value: 0, namely 0dB.

CONNQOFFSET1SN

Parameter name: ConnQoffset1sn



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IDLEQOFFSET1SN Parameter name: IdleQoffset1sn

Offset of cell CPICH RSCP measurement value in cell selection or reselection when the UE is in idle mode

Value range: -50 to +50 .

Physical value range: -50 to +50; step: 1.

Physical unit: dB.

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Content: This parameter is used for moving the border of a cell. The larger the value of this parameter, the lower the probability of neighboring cell selection. Recommended value: 0. Set this parameter through ADD INTRAFREQNCELL / ADD INTERFREQNCELL, query it through LST INTRAFREQNCELL / LST INTERFREQNCELL, and modify it through MOD INTRAFREQNCELL / MOD INTERFREQNCELL.

CONNQOFFSET1SN Parameter name: ConnQoffset1sn

Offset of cell CPICH RSCP measurement value in cell selection or reselection when the UE is in connected mode


Physical value range: -50 to +50 ; step: 1.

Physical unit: dB.


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IDLEQOFFSET2SN

Parameter name: IdleQoffset2sn


CONNQOFFSET2SN

Parameter name: ConnQoffset2sn



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IDLEQOFFSET2SN Parameter name: IdleQoffset2sn

Offset of cell CPICH Ec/No measurement value in cell selection or reselection when the UE is in idle mode


Physical value range: -50 to +50; step: 1.

Physical unit: dB.

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CONNQOFFSET2SN Parameter name: ConnQoffset2sn

Offset of cell CPICH RSCP measurement value in cell selection or reselection when the UE is in connected mode


Physical value range: -50 to +50 ; step: 1.

Physical unit: dB.


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Location Registration z

The location registration includes:

Location update (for non-GPRS)

Route update (for GPRS)


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The location registration is used for the PLMN to trace the current status of the UE and to ensure that the UE is connected with the network when the UE does not perform any operation for a long period.

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Periodic Location Registration z

Periodic location registration is controlled by a Periodic Location Update timer (T3212) or a Periodic Routing Area Update timer (T3312)


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Periodic location registration may be used to periodically notify the network of the availability of the UE.

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T3212 is for non-GPRS operation

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T3312 is for GPRS operation

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Parameters of Location Registration z

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T3212

Parameter name: Periodical location update timer [6min]

Recommended value: 10, namely 60min

ATT

Parameter name: Attach/detach indication

Recommended value: ALLOWED


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T3212

Parameter name: Periodical location update timer [6min]

Value range: 0~255.

Physical unit: 6 min.

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Content: This parameter indicates the time length of the periodical location update. Periodical location update is implemented by MS through the location update procedure. 0: The periodical update procedure is not used. This parameter is valid only when [CN domain ID] is set as CS_DOMAIN. Recommended value: 10. Set this parameter through ADD CNDOMAIN, query it through LST CNDOMAIN, modify it through MOD CNDOMAIN.

ATT

Parameter name: Attach/detach indication

Value range: NOT_ALLOWED, ALLOWED .

Content: NOT_ALLOWED indicates that MS cannot apply the IMSI attach/detach procedure. ALLOWED indicates that MS can apply the IMSI attach/detach procedure. This parameter is valid only when [CN domain ID] is set as CS_DOMAIN. Recommended value: ALLOWED. Set this parameter through ADD CNDOMAIN, query it through LST CNDOMAIN, modify it through MOD CNDOMAIN.

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Paging Initiation z

CN initiated paging z

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Establish a signaling connection

UTRAN initiated paging z

Trigger the cell update procedure

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Trigger reading of updated system information


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For CN originated paging: In order to request UTRAN connect to UE, CN initiates the paging procedure, transmits paging message to the UTRAN through Iu interface, and UTRAN transmits the paging message from CN to UE through the paging procedure on Uu interface, which will make the UE initiate a signaling connection setup process with the CN. For UTRAN originated paging: When the cell system message is updated: When system messages change, the UTRAN will trigger paging process in order to inform UE in the idle, CELL_PCH or URA_PCH state to carry out the system message update, so that the UE can read the updated system message.

UE state transition: In order to trigger UE in the CELL_PCH or URA_PCH state to carry out state transition (for example, transition to the CELL_FACH state), the UTRAN will perform a paging process. Meanwhile, the UE will initiate a cell update or URA update process, as a reply to the paging.

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Paging Type 1 z

If UE is in CELL_PCH,URA_PCH or IDLE state，the paging message will be transmitted on PCCH with paging type 1 CN

RNC1

RNC2

NODEB1.1

NODEB2.1

UE

PAGING RANAP

RANAP

RANAP

PAGING

RANAP

PCCH: PAGING TYPE 1

PCCH: PAGING TYPE 1


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Paging type 1: The message is transmitted in one LA or RA according to LAI or RAI.

z

Page40

After calculating the paging time, the paging message will be transmitted at that time If UE is in CELL_PCH or URA_PCH state, the UTRAN transmits the paging information in PAGING TYPE 1 message to UE. After received paging message, UE performs a cell update procedure to transit state to CELL_FACH.

As shown in the above figure, the CN initiates paging in a location area (LA), which is covered by two RNCs. After receiving a paging message, the RNC searches all the cells corresponding to the LAI, and then calculates the paging time, at which it will send the PAGING TYPE 1 message to these cells through the PCCH.

41

Paging Type 2 z

If UE is in CELL_DCH or CELL_FACH state，the paging message will be transmitted on DCCH with paging type 2 CN

SRNC

UE

PAGING RANAP

RANAP

DCCH: PAGING TYPE 2 RRC


z

Page41

Paging type 2:

z

RRC

If UE is in CELL_DCH or CELL_FACH state，the paging message will be transmitted on DCCH with paging type 2 The message will be only transmitted in a cell

As shown in the above figure, if the UE is in the CELL_-DCH or CELL_FACH state, the UTRAN will immediately transmit PAGING TYPE 2 message to the paged UE on DCCH channel.

42

Typical Call Flow of UE N SS

U E AS

U E N AS

paging

R R _P A IN G _IN D

M SC paging

RANAP

RANAP

R R _E S T_R E Q (P A G IN G R E S P O N S E )

R R C setup process IN ITIA L_D IR E C T_TR A N S FE R A U TH E N TIC A TIO N

REQUEST

AU TH E N TIC A TIO N

R E SP O N S E

(P A G IN G R E S P O N S E )

R R _S E C U R ITY _C O N TR O L_R E Q (IK C K )

S ecu rity m o de co ntrol S E TU P C A LL C O N FIR M

R A B se tu p pro cess A LE R T CONNECT C O N N E C T A C K N O W LE D G E


z

Page42

Many problems will cause the target UE cannot receive the paging message properly Power setting of paging channel is unreasonable.

Unreasonable paging strategies will result in paging channel congestion, which can cause paging message loss.

Paging parameter is unreasonable

Equipment fault

43

DRX Procedure z

UE receives the paging indicator on PICH periodically, that is the Discontinuous Reception (DRX)

z

The value for the DRX paging cycle length is determined as follows: : DRX Cycle Length ＝ (2^K)×PBP frames


z

z

Page43

In idle mode, the UE can monitor the paging in two modes: one is to decode SCCPCH directly every 10ms, the other is to decode the PICH periodically. The second one is the DRX, which is Discontinuous Reception Mechanism. The paging period formula:

DRX Cycle Length ＝ (2^K)*PBP frames K is the “CN domain specific DRX cycle length coefficient”, which is broadcasted in SIB1. The typical value is 6.

PBP is paging block period, which is 1 for FDD mode

The paging period should be 640ms if K is 6

44

DRX Procedure (Cont.) z

Through DRX, UE only listens to PICH at certain predefined time. And UE will read the paging information on SCCPCH if the paging indicator is 1.

z

The value of the Paging Occasion is determined as follows: Paging Occasion (CELL SFN) = {(IMSI mod M) mod (DRX cycle length div PBP)} * PBP + n * DRX cycle length + Frame Offset


z

Page44

Paging SFN formula: Paging Occasion (CELL SFN) = {(IMSI mod M) mod (DRX cycle length div PBP)} *PBP + n *DRX cycle length + Frame Offset

n =0, 1, 2……and the requirement is the calculated CELL SFN must be below its maximum value 4096

Frame Offset is 0 for FDD mode

M is the number of SCCPCH which carries PCH, and the typical value is 1

The formula cloud be simplified as: SFN = IMSI mod (2^K) + n * (2^K)

45


UE must calculate q to know which PI to monitor in one frame of PICH

z

The q value is achieved by the following formula :

⎛ Np ⎥ ⎞ ⎢ q = ⎜⎜ PI + ⎢((18 × (SFN + ⎣SFN / 8⎦ + ⎣SFN / 64⎦ + ⎣SFN / 512⎦)) mod144)× ⎟ mod Np 144 ⎥⎦ ⎟⎠ ⎣ ⎝ z

Where, PI = (IMSI div 8192) mod NP


z z

Page45

SFN is the paging occasion of the UE As shown in the followed figure, the UE needs to monitor the frames (paging occasions) indicated by the red dots, and then decodes the qth PI of this frame.

One DRX cycle

2^K-1

¡ ¡£ ¡ £¡ £ ¡¡£ ££ 4095

0

PI PI 0 1

¡ £ ¡ £ ¡ £P I q

¡ £ ¡ £ ¡ £

PI NP-1

46


Time offset between PICH and S-CCPCH

PICH frame containing paging indicator Associated S-CCPCH frame τPICH


z

Page46

The timing relationship between PICH and S-CCPCH is defined by the above figure, and the interval is 3 slots duration (2ms, 7680 chips).

47

Parameters of DRX z

z

DRXCYCLELENCOEF

Parameter name: DRX cycle length coefficient

Recommended value: 6

PICHMODE

Parameter name: PICH mode

Recommended value: V36.


z

DRXCYCLELENCOEF Parameter name: DRX cycle length coefficient

z

Page47

Value range: 6~9 . Content: This parameter is broadcasted on SIB1. This parameter is used when a UE is in idle mode. Recommended value: 6. Set this parameter through ADD CNDOMAIN, query it through LST CNDOMAIN, and modify it through MOD CNDOMAIN.

PICHMODE Parameter name: PICH mode

Value range: V18, V36, V72, V144 .

Physical value range: 18, 36, 72, 144 .

Content: Indicating the number of PIs contained in each frame on the PICH.

Recommended value: V36 .

Set this parameter through ADD PICH, query it through LST PICH.

48

Parameters of DRX z

MACCPAGEREPEAT

Parameter name: Number of page re-TX



z

Page48

MACCPAGEREPEAT Parameter name: Number of page re-TX

Number of retransmissions of paging message

Value range: 0~2 .

Content: If the number of retransmissions of paging message exceeds this parameter value, retransmissions stop. Recommended value: 1. Set this parameter through SET WFMRCFGDATA, query it through LST WFMRCFGDATA.

49



Page49

50

Two Working Mode of UE z

Idle mode

z

After turning on, UE will stay in idle mode

Connected mode

UE will switch to connected mode which could be CELL_FACH state or CELL_DCH state from the idle mode

After releasing RRC connection, UE will switch to the idle mode from the connected mode


z

z z

Page50

The most important difference between idle mode and connected mode is whether UE has RRC connection with UTRAN or not. In idle mode, UE will be identified by IMSI, TMSI or PTMSI and so on. In connected mode, UE will be identified by URNTI (UTRAN Radio Network Temporary Identity), which is the ID of one RRC connection.

51

Random Access Procedure z

Definition

Random access procedure is initiated by UE in order to get service from the system. Meanwhile, the access channels are allocated to the UE by system


z

Page51

This process may happen in the following scenarios: Attach and detach

LA update and RA update

Signaling connection for services

52

Random Access Channel z

Definition

AICH access slots

SFN mod 2 = 0 τp-a

#0 PRACH access slots

#0

#1

#2

#1

#3

#2

#4

#3

#5

#4

#6

SFN mod 2 = 1 #5

#6

#7

#8

Access slot set 1

#7

#9

#8

#9

#10

#11

z z

z

#11

#12

#13

#12

#13

#14

#14

Access slot set 2

10 ms


#10

10 ms

Page52

UE will transmit the preamble at the access time slot Each 20ms access frame is composed of two 10ms radio frames, which is divided into 15 access time slot, and 5120 chips for each slot The PRACH access slots, AICH access slots and their time offset are showed in the above figure

53

RACH Sub-Channels z

The access slots of different RACH sub-channels are illustrated by the following table SFN mod 8

Random access sub-channels number 0

1

2

3

4

5

6

7

0

0

1

2

3

4

5

6

7

1

12

13

14

2

0

3

9

10

4

6

7

5 6

3

4

1

3

4

9

10

11

8

9

10

11

5

6

7

11 12 13 14

8 0

1

2

3

4

5

0

1

2

10 11 12 13

14

8

9

10 11 12 13 14

5

6

7

7 Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

z

2

8

8

9

Page53

A RACH sub-channel defines a sub-set of the total set of uplink access slots. There are a total of 12 RACH sub-channels.

54

Access Service Class z

The PRACH resources can be classified into several ASCs, so as to provide RACH applications with different priorities.


z

z

z

z

Page54

For Frequency Division Duplex (FDD) mode, the PRACH resources include access timeslots and preamble signatures, which can be classified into several ASCs, so as to provide RACH applications with different priorities. The ASCs range from 0 to 7, and the quantity of ASCs is 8. "0" indicates the highest priority and "7" indicates the lowest priority. The system will assign random access sub-channels and signatures according to the ASC (Access Service Class ) of UE. Set ASC of PRACH through ADD PRACHASC, modify it through MOD PRACHASC, and remove it through RMV PRACHASC.

55

Access Control z

“Access Control” is used by network operators to prevent overload of radio access channels under critical conditions.

Access class 0~Access Class 9

Access class 11~Access Class 15

Access class 10


Page55

z

The access class number is stored in the SIM/USIM.

z

Access class 0~9 are allocated to all the users. And the 10 classes show the same priority.

z

z

Access class 11~15 are allocated to specific high priority users as follows. (The enumeration is not meant as a priority sequence): Access class 15: PLMN staff

Access class 14: users subscribing to emergency services

Access class 13: public organizations

Access class 12: users subscribing to security services

Access class 11: users responsible for PLMN management

Access Class 10 indicates whether or not network access for Emergency Calls is allowed for UEs with access classes 0 to 9 or without an IMSI. For UEs with access classes 11 to 15, Emergency Calls are not allowed if both "Access class 10" and the relevant Access Class (11 to 15) are barred. Otherwise, Emergency Calls are allowed.

56

Mapping between AC and ASC z

The AC-ASC mapping information is optional and used for the System Information Block 5 (SIB5) only.


z

Page56

Set the mapping between AC and ASC through ADD PRACHACTOASCMAP, modify it through MOD PRACHACTOASCMAP, and remove it through RMV PRACHACTOASCMAP.

57

Random Access Procedure START

Choose a RACH sub channel from available ones

Get available signatures

Set Preamble Retrans Max

Set Preamble_Initial_Power

Send a preamble

No AI Choose a access slot again

Check the corresponding AI Get positive AI

Choose a signature and increase preamble transmit power

The counter of preamble retransmit Subtract-1, Commanded preamble power increased by Power Ramp Step

Y

Counter> 0 & Preamble power-maximum allowed power <6 dB

Get negative AI

Increase message part power by p-m based on preamble power

Send the corresponding message part

Set physical status to be RACH message transmitted

Set physical status to be Nack on AICH received

N Set physical status to be Nack on AICH received

Report the physical status to MAC

END 58

z

Physical random access procedure

1. Derive the available uplink access slots, in the next full access slot set, for the set of available RACH sub-channels within the given ASC. Randomly select one access slot among the ones previously determined. If there is no access slot available in the selected set, randomly select one uplink access slot corresponding to the set of available RACH sub-channels within the given ASC from the next access slot set. The random function shall be such that each of the allowed selections is chosen with equal probability 2. Randomly select a signature from the set of available signatures within the given ASC

3. Set the Preamble Retransmission Counter to Preamble_ Retrans_ Max

4. Set the parameter Commanded Preamble Power to Preamble_Initial_Power

5. Transmit a preamble using the selected uplink access slot, signature, and preamble transmission power 6. If no positive or negative acquisition indicator (AI ≠ +1 nor –1) corresponding to the selected signature is detected in the downlink access slot corresponding to the selected uplink access slot:

B: select a signature

C: Increase the Commanded Preamble Power

A: Select the next available access slot in the set of available RACH subchannels within the given ASC

D: Decrease the Preamble Retransmission Counter by one. If the Preamble Retransmission Counter > 0 then repeat from step 6. Otherwise exit the physical random access procedure

7. If a negative acquisition indicator corresponding to the selected signature is detected in the downlink access slot corresponding to the selected uplink access slot, exit the physical random access procedure Signature 8. If a positive acquisition indicator corresponding to the selected signature is detected , Transmit the random access message three or four uplink access slots after the uplink access slot of the last transmitted preamble 9. Exit the physical random access procedure

59

RRC Connection Message z

Typical RRC connection messages

RRC_CONNECTION_REQUEST

RRC_CONNECTION_SETUP

RRC_CONNECTION_SETUP_COMPLETE

RRC_CONNECTION_RELEASE


z

Page59

When a UE needs network service, it first sets up RRC connection as follows: The UE sends a RRC CONNECTION REQUEST message from the cell where it camps to the RNC.

The RNC allocates related resources for the UE and sends an RRC CONNECTION SETUP message to the UE. The UE sends a RRC CONNECTION SETUP COMPLETE message to the RNC. The RRC connection setup ends.

60

UE Timers and Constants in Idle Mode z

z

T300

Parameter name: Timer 300 [ms]

Recommended value: D2000, namely 2000ms

N300

Parameter name: Constant 300



z

T300

z

Page60

Parameter name: Timer 300[ms] Value range: D100, D200, D400, D600, D800, D1000, D1200, D1400, D1600, D1800, D2000, D3000, D4000, D6000, D8000 . Physical value range: 100, 200, 400, 600, 800, 1000, 1200, 1400, 1600, 1800, 2000, 3000, 4000, 6000, 8000 Physical unit: ms Content: T300 is started after the UE transmits the RRC CONNECTION REQUEST message and stopped after the UE receives the RRC CONNECTION SETUP message. RRC CONNECTION REQUEST resents upon the expiry of the timer if V300 less than or equal to N300. Otherwise, the UE enters idle mode. Recommended value: D2000. Set this parameter through SET IDLEMODETIMER, query it through SET IDLEMODETIMER.

N300


Value range: 0~7 .

Content: Maximum number of retransmission of RRC CONNECTION REQUEST .

Recommended value: 3.

Set this parameter through SET IDLEMODETIMER, query it through SET IDLEMODETIMER.

61

UE Timers and Constants in Idle Mode z

z

T312

Parameter name: Timer 312 [s]

Recommended value: 6, namely 6s

N312


Recommended value: D1, namely 1


z

T312

Parameter name: Timer 312[s]

Value range: 1~15 .

Physical value range: 1~15s

Physical unit: s

z

Page61

Content: T312 is started after the UE starts to establish a DCH and stopped when the UE detects N312 consecutive "in sync" indications from L1. It indicates physical channel setup failure upon the expiry of the timer. Recommended value: 6. Set this parameter through SET IDLEMODETIMER, query it through SET IDLEMODETIMER.

N312


Value range: D1, D2, D4, D10, D20, D50, D100, D200, D400, D600, D800, D1000 .

Physical value range: 1, 2, 4, 10, 20, 50, 100, 200, 400, 600, 800, 1000

Content: Maximum number of consecutive "in sync" indications received from L1. .

Recommended value: D1.

Set this parameter through SET IDLEMODETIMER, query it through SET IDLEMODETIMER.

62

RRC Connection Establish Channel Type and Bit Rate z

z

RRCCAUSE

Parameter name: Cause of RRC connection establishment

Recommended value: none

SIGCHTYPE

Parameter name: Channel type for RRC establishment

Recommended value: none


z

RRCCAUSE Parameter name: Cause of RRC connection establishment

Value range: ORIGCONVCALLEST, ORIGSTREAMCALLEST, ORIGINTERCALLEST, ORIGBKGCALLEST, ORIGSUBSTRAFFCALLEST, TERMCONVCALLEST, TERMSTREAMCALLEST, TERMINTERCALLEST, TERMBKGCALLEST, EMERGCALLEST, INTERRATCELLRESELEST, INTERRATCELLCHGORDEREST, REGISTEST, DETACHEST, ORIGHIGHPRIORSIGEST, ORIGLOWPRIORSIGEST, CALLREEST, TERMHIGHPRIORSIGEST, TERMLOWPRIORSIGEST, TERMCAUSEUNKNOWN, DEFAULTEST.

Content: The cause of Rrc connection establishment. .

Recommended value: none.

z

Page62

Set this parameter through SET RRCESTCAUSE, query it through LST RRCESTCAUSE.

SIGCHTYPE Parameter name: Channel type for RRC establishment

Value range: FACH, DCH_3.4K_SIGNALLING, DCH_13.6K_SIGNALLING. Content: FACH indicates that the RRC is established on the common channel. DCH_3.4K_SIGNALLING indicates that the RRC is established on the dedicated channel of 3.4 kbit/s. DCH_13.6K_SIGNALLING indicates that the RRC is established on the dedicated channel of 13.6 kbit/s. . Recommended value: none. Set this parameter through SET RRCESTCAUSE, query it through LST RRCESTCAUSE.

63

RRC Connection Establish Channel Type and Bit Rate z

INTRAMEASCTRL

Parameter name: IntraMeas Ctrl Ind for RRC establishment

Recommended value: SUPPORT


z

Page63

INTRAMEASCTRL Parameter name: IntraMeas Ctrl Ind for RRC establishment

Value range: NOT_SUPPORT, SUPPORT. Content: NOT_SUPPORT indicates that the Intrafreq measurement control message will be send in RRC Connection Establishment. SUPPORT indicates that the Intrafreq measurement control will not be send in RRC Connection Establishment. Recommended value: SUPPORT . Set this parameter through SET RRCESTCAUSE, query it through LST RRCESTCAUSE.

64

Thank you www.huawei.com

65

WCDMA Power Control and Relevant Parameters

www.huawei.com


263

Objectives z

Upon completion of this course, you will be able to:

Describe the purpose and function of power control

Explain open loop power control and parameters

Explain inner loop power control and relevant parameters

Explain outer loop power control and relevant parameters


Page1

264

Contents 1. Power Control Overview 2. Open Loop Power Control 3. Closed Loop Power Control


Page2

265



Page3

266

Purpose of Uplink Power Control z

z

Uplink Transmission Character

Self-interference system

Uplink capacity is limited by interference level

Near-far effect

Fading

Uplink Power Control Function

Ensure uplink quality with minimum transmission power

Decrease interference to other UE, and increase capacity

Solve the near-far effect

Save UE transmission power


Page4

z

CDMA system have the embedded characteristics of self-interference, for uplink one user’s transmission power become interference to others.

z

The more connected users, the higher interference. Generally the capacity is limited by interference level.

z

WCDMA suffer from Near-far effect, which means if all UE use the same transmission power, the one close to the NodeB may block the entire cell.

z

Uplink power control can guarantee the service quality and minimize the required transmission power. It will resolve the near-far effect and resist fading of signal propagation. By lowering the uplink interference level, the system capacity will be increased.

267

Purpose of Downlink Power Control z

z

Downlink Transmission Character

Interference among different subscribers

Interference from other adjacent cells

Downlink capacity is limited by NodeB transmission power

Fading

Downlink Power Control Function

Ensure downlink quality with minimum transmission power

Decrease interference to other cells, and increase capacity

Save NodeB transmission power


Page5

z

The downlink has different characteristics from the uplink, for downlink interference is caused by multi-path, part of one user’s power also become interference to others.

z

Downlink power from adjacent cells also is one part of interference to the own cell.

z

Transmission power of NodeB is shared by all users channels, so downlink capacity usually is considered to be limited by transmission power.

z

Downlink power control also can guarantee the service quality and minimize the required transmission power, so the capacity is maximized in case that interference is lowered.

268

Effect of Power Control 20 Channel Fading

15

Transmitting power Receiving power

Relative power (dB)

10

5

0 -5

-10 -15 -20 0

200

400

600

800

Time (ms) Copyright © 2006 Huawei Technologies Co., Ltd. All rights reserved.

Page6

z

Because of channel fading in mobile communication system, the radio signal is deteriorated and fluctuated, the fast power control become one key technology to resist this phenomenon.

z

In this figure, the channel fading is compensated by the transmitting power, which is adjusted by the fast power control, so the receiving power is almost constant and the radio propagation condition is improved.

269

Power Control Classification z

Open Loop Power Control

z

Uplink / Downlink Open Loop Power Control

Closed Loop Power Control

Uplink / Downlink Inner Loop Power Control

Uplink / Downlink Outer Loop Power Control


Page7

z

In WCDMA system, power control includes open loop and closed loop power control.

z

Open loop power control is used to determine the initial transmission power, and the closed loop power control adjusts the transmission power dynamically and continuously during the connection.

z

For uplink, the UE’s transmission power is adjusted; and for downlink, the NodeB’s transmission power is adjusted.

270

Power Control For Physical Channels z

Power control methods are adopted for these physical channels:

“√" – can be applied, “×" – not applied Closed Loop Power Control

Physical Channel

Open Loop Power Control

Inner Loop Power Control

Outer Loop Power Control

DPDCH

√

√

√

×

DPCCH

√

√

√

×

SCH

×

×

×

√

PCCPCH

×

×

×

√

SCCPCH

×

×

×

√

PRACH

√

×

×

×

AICH

×

×

×

√

PICH

×

×

×

√


z

No Power Control

Page8

Open loop power control is used in two cases:

1. to decide the initial transmission power of PRACH preamble.

2. to decide the initial transmission power of DPCCH / DPDCH.

z

Closed loop power control is only applied on DPCCH and DPDCH

z

For other common channels, power control is not applied, they will use fixed transmission power:

The PCPICH power is defined by the PCPICH TRANSMIT POWER parameter as an absolute value in dBm.

All other common channels power is defined in relation with the PCPICH TRANSMIT POWER parameter, and measured in dB.

271

Common Physical Channel Power Parameters z

z

MAXTXPOWER

Parameter name: Max transmit power of cell

The recommended value is 430, namely 43dBm

PCPICHPOWER

Parameter name: PCPICH transmit power



z

z

Page9

MAXTXPOWER

Parameter name: Max transmit power of cell

Value Range: 0 to 500

Physical Value Range: 0dBm to 50 dBm, step 0.1dB


Content: The sum of the maximum transmit power of all DL channels in a cell.

Set this parameter through ADD CELLSETUP, query it through LST CELL and modify it through MOD CELL

PCPICHPOWER

Parameter name: PCPICH transmit power

Value Range: -100 to 500

Physical Value Range: -10dBm to 50 dBm, step 0.1dB


Content: This parameter should be set based on the actual environment and the downlink coverage should be guaranteed firstly. If PCPICH transmit power is configured too great, the cell capacity will be decreased, for power resources is occupied by common channel and the interference to traffic channels is also increased.

Set this parameter through ADD PCPICH, query it through LST PCPICH and modify it through MOD CELL 272


z

PSCHPOWER or SSCHPOWER

Parameter name: PSCH / SCCH transmit power

The recommended value is -50, namely -5dB

BCHPOWER

Parameter name: BCH transmit power



z

Page10

PSCHPOWER or SSCHPOWER

Parameter name: PSCH / SCCH transmit power

Value range: -350 to 150.

Physical value range: -35 to 15, step 0.1dB


Content: The offset between the PSCH / SSCH transmit power and PCPICH transmit power.

z

For PSCH Power, set it through ADD PSCH, and query it through LST PSCH; for SSCH Power, set it through ADD SSCH, and query it through LST SSCH. And modify it through MOD CELL

BCHPOWER

Parameter name: BCH transmit power

Value Range：-350 to 150

Physical Value Range：-35 to 15 dB, step 0.1dB


Content: The offset between the BCH transmit power and PCPICH transmit power.

Set this parameter through ADD BCH, query it through LST BCH, and modify it through MOD CELL

273


z

MAXFACHPOWER

Parameter name: Max transmit power of FACH

The recommended value is 10, namely 1dB

PCHPOWER

Parameter name: PCH transmit power



z

MAXFACHPOWER

Parameter name: Max transmit power of FACH

Value range : -350 to 150



z

Page11

Content: The offset between the FACH transmit power and PCPICH transmit power. Set this parameter through ADD FACH, query it through LST FACH, and modify it through MOD SCCPCH

PCHPOWER

Parameter name: PCH transmit power




Content: The offset between the PCH transmit power and PCPICH transmit power. Set this parameter through ADD PCH, query it through LST PCH, and modify it through MOD SCCPCH

274


z

AICHPOWEROFFSET

Parameter name: AICH power offset

The default value of this parameter is -6, namely -6dB

PICHPOWEROFFSET

Parameter name: PICH power offset



z

AICHPOWEROFFSET

Parameter name: AICH power offset

Value Range： -22 to 5

Physical Value Range： -22 to 5 dB, step 1dB


z

Page12

Content: The offset between the AICH transmit power and PCPICH transmit power. Set this parameter through ADD CHPWROFFSET, query it through LST CHPWROFFSET, and modify it through MOD AICHPWROFFSET

PICHPOWEROFFSET

Parameter name: PICH power offset


Physical Value Range：-10 to 5 dB , step 1dB


Content: The offset between the PICH transmit power and PCPICH transmit power. Set this parameter through ADD CHPWROFFSET, query it through LST CHPWROFFSET, and modify it through MOD PICHPWROFFSET

275



Page13

276

Contents 2. Open Loop Power Control 2.1 Open Loop Power Control Overview 2.2 PRACH Open Loop Power Control 2.3 Downlink Dedicated Channel Open Loop Power Control 2.4 Uplink Dedicated Channel Open Loop Power Control


Page14

277

Open Loop Power Control Overview z

Purpose

z

z

Calculate the initial transmission power of uplink / downlink channels

Principle

Estimates the downlink signal power loss on propagation path

Path loss of the uplink channel is related to the downlink channel

Application

Open loop power control is applied only at the beginning of connection setup to set the initial power value.


Page15

z

In downlink open loop power control, the initial transmission power is calculated according to the downlink path loss between NodeB and UE.

z

In uplink, since the uplink and downlink frequencies of WCDMA are in the same frequency band, a significant correlation exists between the average path loss of the two links. This make it possible for each UE to calculate the initial transmission power required in the uplink based on the downlink path loss.

z

However, there is 90MHz frequency interval between uplink and downlink frequencies, the fading between the uplink and downlink is uncorrelated, so the open loop power control is not absolutely accurate.

278



Page16

279

PRACH Open Loop Power Control Serving RNC

Node B

UE

1. CCCH: RRC Connection Request RRC

RRC

Open loop power control of PRACH

Allocate RNTI Select L1 and L2 parameters 2. Radio Link Setup Request NBAP

NBAP

Start RX description 3. Radio Link Setup Response NBAP

NBAP 4. ALCAP Iub Data Transport Bearer Setup DCH - FP DCH - FP

5. Downlink Synchronization 6. Uplink Synchronization

DCH - FP DCH - FP

Start TX description RRC

7. CCCH: RRC Connection Set up

RRC

8. Radio Link Restore Indication NBAP RRC

NBAP

9. DCCH: RRC Connection Setup Complete


RRC

Page17

z

In access procedure, the first signaling “RRC CONNECTION REQUEST” is transmitted in message part on PRACH.

z

Before PRACH message part transmission, UE will transmit PRACH preamble, and the transmission power of first preamble is calculated by this PRACH open loop power control.

280

PRACH Open Loop Power Control z

Initial Power Calculation for the First Preamble

When UE needs to set up a RRC connection, the initial power of uplink PRACH can be calculated according to the following formula:

Preamble_I nitial_Pow er = PCPICH Transmit Power - CPICH_RSCP + UL Interferen ce + Constant Value For Calculatin g Initial Tx Power


z

Page18

In this formula, where

PCPICH TRANSMIT POWER defines the PCPICH transmit power in a cell. It is broadcast in SIB5.

CPICH_RSCP means received signal code power, the received power measured on the PCPICH. The measurement is performed by the UE.

UL interference is the UL RTWP measured by the NodeB. It is broadcast in SIB7.

CONSTANT VALUE compensates for the RACH processing gain. It is broadcast in SIB5.

z

The initial value of PRACH power is set through open loop power control. UE operation steps are as follows:

1. Read “Primary CPICH DL TX power”, “UL interference” and “Constant value” from system information.

2. Measure the value of CPICH_RSCP;

3. Calculate the Preamble_Initial_Power of PRACH.

281

PRACH Open Loop Power Control Parameters z

CONSTANTVALUE

Parameter name: Constant value for calculating initial TX power



z

Page19

CONSTANTVALUE

Parameter name: Constant value for calculating initial TX power

Value range : -35 ~ -10

Physical Value Range：-35 to -10 dB

Content: It is used to calculate the transmit power of the first preamble in the random access process.

Recommended value: -20

Set this parameter through ADD PRACHBASIC, query it through LST PRACH, and modify it through MOD PRACHUUPARAS

282


Timing relationship of PRACH and AICH

1 access slot Acq. Ind.

AICH

τ p-a

PRACH

Preamble

Preamble

τ p-p


Message part

τ p-m

Page20

z

After UE transmit the first Preamble on PRACH, it will wait for the corresponding AI (Acquisition Indicator) on the AICH. The timing relationship of PRACH and AICH is shown in above figure.

z

There will be 3 parameters used to define the timing relationship:

τp-p: time interval between two PRACH preambles. τp-p is not a fixed value, it is decided by selecting access slot of PRACH preambles, Here τp-p has one restriction, it must be longer than a minimum value τp-p min , namely τp-p ≥ τp-p min.

τp-a: time interval between PRACH preamble and AICH Acquisition Indicator. If UE sends the PRACH preamble, it will detect the responding AI after τp-a time. τp-m: time interval between PRACH preamble and PRACH message part. If UE sends the PRACH preamble and receives positive AI from the AICH, it will send the message part after τp-m time.

283


AICHTXTIMING

Parameter name: AICH transmission timing

Content:

When AICHTXTIMING = 0,

τp-p,min = 15360 chips, τp-a = 7680 chips, τp-m = 15360 chips



The recommended value is 1


Page21

z

Parameter AICHTXTIMING is used to define the set of τp-p min, τp-a, τp-m.

z

AICHTXTIMING

Parameter name: AICH transmission timing

Value range：0,1

Content:






Set this parameter through ADD AICH, query it through LST AICH, and modify it needs de-activated the cell through DEA CELL. After the old configuration of AICH is deleted through RMV AICH , a new AICH can be established through ADD AICH

284


Power Ramping for Preamble Retransmission

Power Offset Pp-m Power Ramp Step

Preamble_Initial _Power

Preamble

＃1

Preamble

＃2

Preamble

……

＃3


z

Preamble

Message part

＃N

Page22

After UE transmit the first Preamble,

If no positive or negative AI on AICH is received after τp-a time,

UE shall increase the preamble power by POWER RAMP STEP, and retransmit the preamble. This ramping process stops until the number of transmitted preambles has reached the MAX PREAMBLE RETRANSMISSION within an access cycle, or when the maximum number of access cycles has reached MAX PREAMBLE LOOP.

If a negative AI on AICH is received by the UE after τp-a time,

which indicates rejection of the preamble, the UE shall wait for a certain “Back-off Delay” and re-initiate a new random access process.

When a positive AI on AICH is received by UE after τp-a time,

it will transmit the random access message after the uplink access slot of the last preamble. The transmit power of the random access message control part should be POWER OFFSET higher than the power of the last transmitted preamble.

285


z

POWERRAMPSTEP

Parameter name: Power increase step


PREAMBLERETRANSMAX

Parameter name: Max preamble retransmission

The Recommended value is 20


z

Page23

POWERRAMPSTEP

Parameter name: Power increase step

Value range : 1 to 8

Physical Value Range: 1 to 8 dB

Content: The power increase step of the random access preambles transmitted before the UE receives the acquisition indicator in the random access process.



z

PREAMBLERETRANSMAX

Parameter name: Max preamble retransmission


Content: The maximum number of preambles transmitted in a preamble ramping cycle.



286


z

MMAX

Parameter name: Max preamble loop

The recommended value is 8

NB01MIN / NB01MAX

Parameter name: Random back-off lower / upper limit

The recommended value: 0 for both NB01MIN / NB01MAX


z

MMAX

Parameter name: Max preamble loop

Value range: 1 to 32

Content: The maximum number of random access preamble loops.


z

Page24

Set this parameter through ADD RACH, query it through LST RACH, and modify it first de-activated the cell through DEA CELL, then MOD RACH.

NB01MIN / NB01MAX

Parameter name: Random back-off lower / upper limit


Content: The lower / upper limit of random access back-off delay.

The recommended value: 0 for both NB01MIN / NB01MAX

Set this parameter through ADD RACH, query it through LST RACH, and modify it first de-activated the cell through DEA CELL, then MOD RACH.

287


POWEROFFSETPPM

Parameter name: Power offset

The default value: -3dB for signalling transmission; -2dB for service transmission.


z

Page25

POWEROFFSETPPM

Parameter name: Power offset

Value range: -5 to 10dB

Content: The power offset between the last access preamble and the message control part. The power of the message control part can be obtained by adding the offset to the access preamble power. The recommended value of this parameter is -3dB for signalling transmission , and that -2dB for service transmission

Set this parameter through ADD PRACHTFC, query it through LST PRACH, and modify it de-activated the cell through DEA CELL . After the old configuration of PRACH is deleted through RMV PRACHTFC , a new parameters can be established through ADD PRACHTFC

z

The PRACH message also consists of control part and data part, here the POWER OFFSET is the difference between the PRACH preamble and the message control part.

z

The PRACH message uses GAIN FACTOR to set the power of control / data part:

GAIN FACTOR BETAC ( βc ) is the gain factor for the control part.

GAIN FACTOR BETAD ( βd ) is the gain factor for the data part.

288



Page26

289

DL DPDCH Open Loop Power Control Serving RNC

Node B

UE

1. CCCH: RRC Connection Request RRC

RRC

Allocate RNTI Select L1 and L2 parameters 2. Radio Link Setup Request NBAP

NBAP


NBAP 4. ALCAP Iub Data Transport Bearer Setup

DL DPDCH Open Loop Power Control

DCH - FP DCH - FP


DCH - FP DCH - FP

Start TX description RRC

7. CCCH: RRC Connection Set up

RRC

8. Radio Link Restore Indication NBAP

NBAP RRC



RRC

Page27

z

According to the RRC connection establishment procedure, after RNC received the “RRC CONNECTION REQUEST” message, and NodeB set up the radio link for UE, then Iub interface resources is established between NodeB and RNC.

z

When DCH-FP of Iub interface finished downlink and uplink synchronization, the downlink DPCH starts to transmit, and DPDCH initial transmission power is calculated through open loop power control.

290

DL DPDCH Open Loop Power Control z

When a dedicated channel is set up, the initial power of downlink DPDCH can be calculated according to the following formula:

PInitial =

⎞ ⎛ PCPICH R Eb )DL × ⎜⎜ ×( − αPTotal ⎟⎟ W No ⎠ ⎝ ( Ec / No )CPICH


z

Page28

In this formula, where

R is the requested data bitrate by the user

W is the chip rate

(Eb/No)DL is the Eb/No target to ensure the service quality. RNC searches for the (Eb/No)DL dynamically in a set of pre-defined values according to specific cell environment type, coding type, bitrate, BLER target and etc.

(Ec/Io)CPICH is the CPICH signal quality measured by UE, then it is sent to RNC through RACH.

α is the orthogonality factor in the downlink. In Huawei implementation, α is set to 0.

z

Ptotal is the total carrier transmit power measured at the NodeB

The initial transmission power of downlink DPDCH could be calculated through this formula, then, initial transmission power of downlink DPCCH can be obtained according to the power offset: PO1, PO2 and PO3.

291

DL DPDCH Open Loop Power Control

1 timeslot Downlink Transmit Power

PO2

PO1 PO3

Data1 DPDCH

TPC

TFCI

DPCCH

Data2

Pilot

DPDCH

DPCCH


z

Page29

This figure shows the power offset of downlink DPCH :

PO1 is the power offset of DPCCH TFCI bits to DPDCH data bits.

PO2 is the power offset of DPCCH TPC bits to DPDCH data bits.

PO3 is the power offset of DPCCH Pilot bits to DPDCH data bits.

The values of PO1, PO2 and PO3 are configured on RNC.

292

DL DPDCH Open Loop Power Control Parameter z

z

TFCIPO

Parameter name: TFCI power offset


TPCPO

Parameter name: TPC power offset



z

TFCIPO

Parameter name: TFCI power offset


Physical value range: 0 to 6 dB, step: 0.25

z

Page30

Content: The offset of TFCI bit transmit power from data bit transmit power in each time slot of radio frames on DL DPCH Recommended value: 0 Set this parameter through SET FRC, query it through LST FRC, and modify it through SET FRC

TPCPO

Parameter name: TPC power offset



Content: The offset of TPC bit transmit power from data bit transmit power in each time slot of radio frames on DL DPCH Recommended value: 12 Set this parameter through SET FRC, query it through LST FRC, and modify it through SET FRC

293

DL DPDCH Open Loop Power Control Parameter z

PILOTPO

Parameter name: Pilot power offset



z

Page31

PILOTPO

Parameter name: Pilot power offset



Content: The offset of pilot bit transmit power from data bit transmit power in each time slot of radio frames on DL DPCH


Set this parameter through SET FRC, query it through LST FRC, and modify it through SET FRC

294

Downlink Power Control Restriction z

The power of downlink dedicated channel is limited by an upper and lower limit for each radio link.

The DL DPDCH power could not exceed Maximum_DL_Power, nor could it be below Minimum_DL_Power.

z

RLMAXDLPWR / RLMINDLPWR

Parameter name: RL Max / Min DL TX power

The recommended value is shown in the following table.


Page32

z

Note: Both downlink open loop and close loop power control will be limited by this parameter.

z

RLMAXDLPWR

z

Parameter name: RL Max DL TX power



Content: The maximum downlink transmit power of radio link. This parameter should fulfill the coverage requirement of the network planning, and the value is relative to [PCPICH transmit power]

Set this parameter through ADD CELLRLPWR , query it through LST CELLRLPWR, and modify it through MOD CELLRLPWR

RLMINDLPWR

Parameter name: RL Min DL TX power



Content: The minimum downlink transmit power of radio link. This parameter should consider the maximum downlink transmit power and the dynamic range of power control, and the value is relative to [PCPICH transmit power]. Since the dynamic range of power control is set as 15dB, this parameter is recommended as [RL Max DL TX power] – 15 dB.

Set this parameter through ADD CELLRLPWR, query it through LST CELLRLPWR, and modify it through MOD CELLRLPWR

295

Downlink Power Restriction Parameters z

Referential configurations for typical services: Service

RL Max Downlink Transmit Power

RL Min Downlink Transmit Power

Downlink SF

CS Domain 12.2 kbps AMR

-3

-18

128

28 kbps

-2

-17

64

32 kbps

-2

-17

64

56 kbps

0

-15

32

64 kbps

0

-15

32

PS Domain 8 kbps

-8

-23

128

32 kbps

-4

-19

64

64 kbps

-2

-17

32

144 kbps

0

-15

16

256 kbps

2

-13

8

384 kbps

4

-11

8


Page33

296



Page34

297

UL DPCCH Open Loop Power Control Serving RNC

Node B

UE

1. CCCH: RRC Connection Request

RRC

RRC Allocate RNTI Select L1 and L2 parameters

2. Radio Link Setup Request NBAP

NBAP


NBAP 4. ALCAP Iub Data Transport Bearer Setup DCH - FP DCH - FP


DCH - FP DCH - FP

Start TX description 7. CCCH: RRC Connection Set up

RRC

Open Loop Power Control of UL DPCCH RRC

NBAP



z

RRC

8. Radio Link Restore Indication NBAP

RRC

Page35

According to the RRC connection establishment procedure, after RNC sent the “RRC CONNECTION SETUP” message, UE will try to synchronize with NodeB, and the uplink DPCCH starts to transmit, here DPCCH initial transmission power is calculated through open loop power control

298

UL DPCCH Open Loop Power Control The initial power of the uplink DPCCH can be calculated according to the following formula:

z

DPCCH _ Initial _ Power = DPCCH _ Power _ Offset − CPICH _ RSCP Where

z

CPICH_RSCP means the received signal code power, the received power measured on the CPICH. DPCCH_Power_Offset is provided by RNC to the UE via RRC signaling.


z

Page36

For Huawei, DPCCH_Power_Offset is calculated with the following formula:

DPCCH _ Power _ Offset = PCPICH Transmit Power + UL Interference + Default Cons tan t Value z

Where

PCPICH Transmit Power defines the PCPICH transmit power in a cell.

UL Interference is the UL RTWP measured by the NodeB.

Default Constant Value reflects the target Ec/No of the uplink DPCCH preamble.

299

UL DPCCH Open Loop Power Control Parameter z

DEFAULTCONSTANTVALUE

Parameter name: Constant value configured by default

The recommended value is -27, namely -27dB.


z

Page37

DEFAULTCONSTANTVALUE

Parameter name: Constant value configured by default

Value range : -35 to -10 , unit :dB

Content: This parameter is used to obtain DPCCH_Power_Offset, which is used by UE to calculate the initial transmit power of UL DPCCH during the open loop power control process.

Recommended value: -27


300

Uplink Power Control Restriction z

During the operation of uplink power control, the UE transmit power shall not exceed the Maximum Allowed Uplink Transmit Power.

z

MAXALLOWEDULTXPOWER


The recommended value is 21, namely 21 dBm.


z

Page38

MAXALLOWEDULTXPOWER


Value range: -50 to 33

Physical value range: -50 to 33 dBm. Step: 1

Content: The maximum allowed uplink transmit power of a UE in the cell, which is related to the network planning.


Set this parameter through ADD CELLSELRESEL, query it through LST CELLSELRESEL, and modify it through MOD CELLSELRESEL

301

Uplink Power Control Restriction z

In addition, there are four parameters which correspond to the maximum allowed transmit power of four classes of services respectively:

z

MAXULTXPOWERFORCONV

z

MAXULTXPOWERFORSTR

z

Parameter name: Max UL TX power of Streaming service

MAXULTXPOWERFORINT

z

Parameter name: Max UL TX power of Conversational service

Parameter name: Max UL TX power of Interactive service

MAXULTXPOWERFORBAC

Parameter name: Max UL TX power of Background service

The recommended value is 24, namely 24 dBm.


z

MAXULTXPOWERFORCONV

z

Parameter name: Max UL TX power of Streaming service

MAXULTXPOWERFORINT

z

Parameter name: Max UL TX power of Conversational service

MAXULTXPOWERFORSTR

z

Page39

Parameter name: Max UL TX power of Interactive service

MAXULTXPOWERFORBAC

Parameter name: Max UL TX power of Background service


Physical value range: -50 to 33 dBm. Step: 1

Content: The maximum UL transmit power for specific service in the cell, which is related to the network planning.


Set this parameter through ADD CELLCAC, query it through LST CELLCAC, and modify it through MOD CELLCAC

302



Page40

303

Contents 3. Closed Loop Power Control 3.1 Closed Loop Power Control Overview 3.2 Uplink Inner Loop Power Control 3.3 Downlink Inner Loop Power Control 3.4 Outer Loop Power Control


Page41

304

Closed Loop Power Control Overview z

Why closed loop power control is needed?

Open loop power control is not accurate enough, it can only estimate the initial transmission power. Closed loop power control can guarantee the QoS with minimum power. By decreasing the interference, the system capacity will be increased. Outer Loop

Inner Loop

SIRmea>SIRtar→ TPC=0

BLERmea>BLERtar→SIRtar SIRtar BLERtar BLER
TPC SIRmea
TPC=1 TPC=0

Power Power

Until SIRmea=SIRtar


Page42

Inner Loop Power Control z

The receiver compares SIRmea (measured SIR) with SIRtar (target SIR), and decide the TPC to send.

z

If SIRmea is greater than SIRtar, the TPC is set as “0” to increase transmission power

If SIRmea is less than SIRtar, the TPC is set as “1” to decrease transmission power

TPC is sent to the transmitter in DPCCH, the transmitter will adjust the power according to the value of received TPC.

z

Through inner loop power control, the SIRmea can be ensured to approach SIRtar.

Outer Loop Power Control z

The receiver compares BLERmea (measured BLER) with BLERtar (target BLER), and decide how to set the SIRtar.

z

If BLERmea is greater than BLERtar, the SIRtar is increased

If BLERmea is less than BLERtar, the SIRtar is decreased

The adjusted SIRtar is sent for the inner loop power control, then it will be used in previous process to guide the transmitter power adjustment.

z

Through outer loop power control, the BLERmea can be ensured to approach BLERtar.

305



Page43

306

Uplink Inner Loop Power Control z

NodeB compares the measured SIR to the preset target SIR, then derives TPC and sends the TPC Decision to UE. TPC Decision ( 0, 1 )

Compare SIRmea with SIRtar SIRmea > SIRtar → TPC = 0 SIRmea ≤ SIRtar → TPC = 1

Single RL / Soft HO PCA1 / PCA2

Generate TPC_cmd ( -1, 0, 1 )

Inner Loop

Adjust DPCCH Tx

Set SIRtar

NodeB

Transmit TPC

UE

△DPCCH =△TPC×TPC_cmd

Adjust DPDCH Tx ( βc , β d )


z

Page44

RNC sends SIRtar (target SIR) to NodeB and then NodeB compares SIRmea (measured SIR) with SIRtar once every timeslot.

If the estimated SIR is greater than the target SIR, NodeB sends TPC “0” to UE on downlink DPCCH TPC field.

z

Otherwise, NodeB sends TPC “1” to UE.

After reception of one or more TPC in a slot, UE shall derive a single TPC_cmd (TPC command, with value among -1,0,1):

For UE is in soft handover state, more than one TPC is received in a slot, so firstly multiple TPC_cmd is combined.

Two algorithms could be used by the UE for deriving the TPC_cmd, those are PCA1 and PCA2 (PCA means Power Control Algorithm).

z

When deriving the combined TPC_cmd, UE shall adjust the transmit power of uplink DPCCH with a step “UL Closed Loop Power Control Step Size“, as following:

z

△DPCCH =△TPC×TPC_cmd

This adjustment is executed on the DPCCH, then associated DPDCH transmit power is calculated according to DPDCH / DPCCH power ratio βd / βc.

307

Uplink Inner Loop PCA1 with Single Radio Link z

For single radio link and PCA1, UE derives one TPC_cmd in each time slot as follows:

TPC

TPC_cmd

……

……

0

1

1

0

1

1

0

1

1

0

…… -1

1

1

-1

1

1

-1

1

1

-1 ……

This control is performed in each time slot, so the power control frequency is 1500Hz


z

z

Page45

When UE has single radio link, only one TPC will be received in each slot. In this case, the value of TPC_cmd shall be derived by PCA1 as follows:

If the received TPC is equal to 0, then TPC_cmd for that slot is –1.

If the received TPC is equal to 1, then TPC_cmd for that slot is 1.

According to DPCCH channel structure, there are 15 time slots in a 10ms radio frame, and the control is performed once in each time slot, so the frequency of uplink inner loop PCA1 is 1500Hz.

308

Uplink Inner Loop PCA2 with Single Radio Link z

For single radio link and PCA2, UE derives one TPC_cmd in each 5-slot group as follows: 10ms radio frame

TPC

Group 2

Group 1

……

Group 3

TS0

TS1

TS2

TS3

TS4

TS5

TS6

TS7

TS8

TS9

TS10

TS11

TS12

TS13

TS14

0

0

0

0

0

1

1

1

1

1

1

1

0

1

1

0

0

0

0

-1

0

0

0

0

1

0

0

0

0

0

……

……

……

TPC_cmd

This control is performed in each 5-slot group, so the power control frequency is 300Hz


z

z

Page46

When UE has single radio link, only one TPC will be received in each slot. In this case, the value of TPC_cmd shall be derived by PCA2 as follows:

For the first 4 slots of a set, TPC_cmd = 0.

For the fifth slot of a set, UE make the decisions on as follows:

If all 5 TPC within a group are 1, then TPC_cmd = 1 in the 5th slot.

If all 5 TPC within a group are 0, then TPC_cmd = -1 in the 5th slot.

Otherwise, TPC_cmd = 0 in the 5th slot.

According to DPCCH channel structure, there are 15 time slots in a 10ms radio frame, and the control is performed once in each 5-slot group, so the frequency of uplink inner loop PCA2 is 500Hz.

309

Uplink Inner Loop with Soft Handover z

When UE enters soft handover state, on the NodeB side, there are two phases :

z

Uplink synchronization phase

Multi-radio link phase

On UE side, UE will receive different TPCs from different RLS in one time slot. Therefore, the UE should combine all the TPCs to get a unique TPC_CMD.


z

Page47

On the NodeB side, there are two phases during the soft handover state:

Uplink synchronization phase The NodeB should send durative “TPC = 1” to the newly-added RL before successful synchronization.

Multi-radio link phase Each NodeB and each cell will estimate the SIR individually and the general TPC individually. Therefore, the UE may receive different TPC from different RLS.

z

Especially, when UE is in softer handover state, it means UE has radio links to the same NodeB, in this case, these RLs (Radio Link) belong to the same RLS (Radio Link Set), and the all TPCs are the same from each RL.

310

Uplink Inner Loop PCA1 with Soft Handover CELL1

For each slot, combine TPC from the same RLS, then get Wi

CELL2

RL1-1

RL1-2 RLS1

Get TPC_cmd based on TPC_cmd = γ (W1, W2, … WN)

RLS3

RLS2

CELL4

CELL3

RLS1-TPC (W1)

……

0

1

1

0

1

1

0

1

1

0

……

RLS2-TPC (W2)

……

1

0

1

1

0

1

0

1

0

1

……

RLS3-TPC (W3)

……

0

0

1

0

0

1

1

0

1

1

……

TPC_cmd

……

-1 -1

1

-1 -1

1

-1 -1 -1 -1

……


Page48

z

When UE is in soft handover state, multiple TPC will be received in each slot from different cells in the active set. UE will generate the TPC_cmd by PCA1 as follows:

z

1. Combine the TPC from the same RLS and derive the Wi

When the RLs (Radio Link) are in the same RLS (Radio Link Set), they will transmit the same TPC in a slot. In this case, the TPCs from the same RLS shall be combined into one.

z

After combination, UE will obtain a soft symbol decision Wi for each RLSi.

2. Combine the TPC from different RLSs and derive the TPC_cmd

UE derives TPC_cmd, it is based on a function γ and all the N soft symbol decisions Wi: TPC_cmd = γ (W1, W2, … WN), Where TPC_cmd can only take the values 1 or -1.

In Huawei implementation, the function γ shall fulfil the following criteria: If the TPCs from all RLSs are “1”, the output of γ shall be equal to “1” ; If one TPC from any RLS is “0”, the output of γ shall be equal to “-1”.

311

Uplink Inner Loop PCA2 with Soft Handover Combine TPC from same RLS in each time slot CELL1

CELL2

RL1-1

Calculate TPC_cmd If any TPC_tempi = -1, TPC_cmd = -1

If

1 N

N

∑ TPC _ temp i > 0.5 , TPC_cmd = 1

RL1-2 RLS1

Calculate TPC_tempi for each RLSi

RLS2

RLS3

CELL4

CELL3

i =1

Otherwise, TPC_cmd = 0


Page49

z

When UE is in soft handover state, multiple TPC will be received in each slot from different cells in the active set. UE will generate the TPC_cmd by PCA2 as follows:

z

1. Combine the TPC from the same RLS.

When the RLs are in the same RLS, they will transmit the same TPC in a slot. In this case, the TPCs from the same RLS shall be combined into one.

z

2. Calculate the TPC_tempi for each RLS UE derives TPC_tempi through the same way in the last slide, as follows:

z

For the first 4 slots of a group, TPC_tempi = 0.

For the 5th slot of a group:

If all 5 TPCs within a group are 1, then TPC_tempi = 1 in the 5th slot.

If all 5 TPCs within a group are 0, then TPC_tempi = -1 in the 5th slot.

Otherwise, TPC_tempi = 0 in the 5th slot.

3. Calculate the TPC_cmd UE derives TPC_cmd through the following criteria:

If any TPC_tempi is equal to -1, TPC_cmd is set to -1.

If

1 N

N

∑ TPC _ temp

i

> 0.5 , TPC_cmd = 1

i =1

Otherwise, TPC_cmd = 0

312

Uplink Inner Loop PCA2 with Soft Handover 10ms/frame Group 1

Group 2

Group 3

TPC TS0

TS1

TS2

TS3

TS4

TS5

TS6

TS7

TS8

TS9

TS10

TS11

TS12

TS13

TS14

RLS1

0

0

1

0

0

0

0

0

0

0

0

1

0

0

1

RLS2

1

1

1

1

1

0

0

0

0

0

1

1

0

0

1

RLS3

1

1

1

1

1

0

0

0

0

0

1

1

1

1

1

TS14

……

……

TPC_tempi ……

TS0

TS1

TS2

TS3

TS4

TS5

TS6

TS7

TS8

TS9

TS10

TS11

TS12

TS13

RLS1

0

0

0

0

0

0

0

0

0

-1

0

0

0

0

0

RLS2

0

0

0

0

1

0

0

0

0

-1

0

0

0

0

0

RLS3

0

0

0

0

1

0

0

0

0

-1

0

0

0

0

1

TS0

TS1

TS2

TS3

TS4

TS5

TS6

TS7

TS8

TS9

TS10

TS11

TS12

TS13

TS14

0

0

0

0

1

0

0

0

0

-1

0

0

0

0

0

……

TPC_cmd ……


z

……

Page50

The example of the uplink inner loop PCA2 in soft handover state.

313

Uplink Inner Loop Power Control Parameters z

z

PWRCTRLALG

Parameter name: Power control algorithm selection

The recommended value is ALGORITHM1

ULTPCSTEPSIZE

Parameter name: UL closed loop power control step size



z

Page51

PWRCTRLALG

Parameter name: Power control algorithm selection

Value range: ALGORITHM1, ALGORITHM2

Content: This parameter is used to inform the UE of the method for translating the received TPC commands.

Recommended value: ALGORITHM1


z

ULTPCSTEPSIZE

Parameter name: UL closed loop power control step size

Value range :1dB, 2dB

Content: The step size of the closed loop power control performed on UL DPDCH. This parameter is mandatory when the parameter “Power control algorithm selection” is set as "ALGORITHM1".



314



Page52

315

Downlink Inner Loop Power Control z

UE L1 compares the measured SIR to the preset target SIR, then derives TPC and sends the TPC Decision to NodeB. L3 Set SIRtar

Derive TPCest(k) ( 0, 1 ) DPC_MODE

Inner Loop

Generate PTPC(k)

Calculate P(k)

L1 compare SIRmea with SIRtar

NodeB

Derive and transmit TPC based on DPC_MODE

UE

Adjust DPCH Tx Power


z

Page53

Basically the downlink inner loop power control process is similar with uplink, UE L3 sends SIRtar to UE L1 and then UE L1 compares SIRmea with SIRtar :

If the SIRmea is greater than the SIRtar , UE sends TPC “0” to NodeB on uplink DPCCH TPC field.

z

Otherwise, UE sends TPC “1” to NodeB.

The UE shall check the downlink power control mode before generating the TPC, two algorithm DPC_MODE1 and DPC_MODE2 could be used by UE to derive the TPC. Upon receiving the TPC, NodeB shall estimate the transmitted TPC and adjust its downlink DPCCH/DPDCH power accordingly.

z

After reception of one or more TPC in a slot, NodeB shall derive the estimated TPC TPCest(k) and calculate a PTPC(k), the power adjustment of k:th slot.

z

Then NodeB shall adjust the current downlink power P(k-1) to a new power P(k), and adjust the power of the DPCCH and DPDCH with the same amount, since power difference between them is fixed.

316

Downlink Inner Loop Power Control Mode z

Two DPC_MODE (Downlink Power Control Mode) could be used:

If DPC_MODE = 0, UE sends a unique TPC in each slot, UTRAN shall derive TPCest to be 0 or 1, and update the power every slot;

If DPC_MODE = 1, UE repeats the same TPC over 3 slots, UTRAN shall derive TPCest over three slots to be 0 or 1, and update the power every three slots.


Page54

z

The DPC_MODE parameter is a UE specific parameter and controlled by the UTRAN.

z

The UE shall check the DPC_MODE (Downlink Power Control Mode) before generating the TPC, and upon receiving the TPC, the UTRAN shall adjust its downlink power accordingly.

317

Downlink Inner Loop Power Control Parameters z

DPCMODE

Parameter name: Downlink power control mode

The recommended value is SINGLE_TPC, namely DPC_MODE = 0


z

Page55

DPCMODE

Parameter name: Downlink power control mode

Value range: SINGLE_TPC (DPC_MODE=0), TPC_TRIPLET_IN_SOFT (DPC_MODE=1), TPC_AUTO_ADJUST

Content: SIGNLE_TPC, a fast power control mode, indicates that a unique TPC command is sent in each time slot on DPCCH. TPC_TRIPLET_IN_SOFT, a slow power control mode, indicates that the same TPC is sent in three time slots, it is applicable to soft handover and it can decrease the power deviation. TPC_AUTO_ADJUST, an automatically adjusted mode, indicates that the value of DPC_MODE can be modified by sending the message “ACTIVE SET UPDATE” to UE.

Recommended value: SINGLE_TPC Set this parameter through SET FRC, query it through LST FRC, and modify it through SET FRC

318


After estimating the TPC, the UTRAN shall set the downlink power to P(k) for k:th slot according to the following formula:

P ( k ) = P ( k − 1 ) + PTPC ( k ) + Pbal ( k ) Where

P(k-1) is downlink transmission power in (k-1):th slot

PTPC(k) is the adjustment of downlink power in k:th slot

Pbal (k) is correction value according to the downlink power balance procedure. For a single radio link, Pbal (k) equals 0.


z

Page56

If DOWNLINK_POWER_BALANCE_SWITCH is OFF, then Pbal(k) equals 0.

319


PTPC(k) is calculated according to the following:

If the value of “Limited Power Increase Used” parameter is “Not Used” , then:

⎧+ Δ PTPC ( k ) = ⎨ TPC ⎩ − ΔTPC

if TPC est ( k ) = 1 if TPC est ( k ) = 0

Where

TPCest (k) is uplink received TPC of the k:th slot

ΔTPC is downlink power adjustment step size


Page57

320

Downlink Inner Loop Power Control

If the value of “Limited Power Increase Used” parameter is “Used” , then:

⎧+ ΔTPC ⎪ PTPC ( k ) = ⎨0 ⎪− Δ ⎩ TPC

Where

if TPCest ( k ) = 1 and Δsum ( k ) + ΔTPC < Power _ Raise _ Limit if TPCest ( k ) = 1 and Δsum ( k ) + ΔTPC ≥ Power _ Raise _ Limit if TPCest ( k ) = 0

Δsum ( k ) =

k −1

∑

PTPC ( i ) i = k − DL _ Power _ Average _ Window_ Size


Page58

Where, z

Power_Raise_Limit : the restriction value of power increasing within a period

z

DL_Power_Average_Window_Size : the period of DL transmit power increasing.

z

From the definition above, Δsum(k) indicates the sum of downlink power adjustment in the latest DL_Power_Average_Window_Size time slots.

321


INNER_LOOP_DL_LMTED_PWR_INC_SWITCH

This is one switch in PCSWITCH (Power control algorithm switch) parameter.

z

The default value is 0, namely OFF.

POWERRAISELIMIT

Parameter name: Power increase limit

The recommended value is 10dB


z

INNER_LOOP_DL_LMTED_PWR_INC_SWITCH

This is one switch in PcSwitch (Power control algorithm switch) parameter.

Value range：1 (ON) , 0 (OFF)

z

Page59

Content: When it is checked, limited power increase algorithm is applied in the inner loop power control. limited power increase algorithm means that when the DL transmit power is increased, there is a limit for the step, that is, each increase is limited. Recommended value (default value): 0 Set this parameter through SET CORRMALGOSWITCH, query it through LST CORRMALGOSWITCH, and modify it through SET CORRMALGOSWITCH

POWERRAISELIMIT

Parameter name: Power increase limit

Value range: 0 to 10 dB

Content: The increase of DL transmit power within DL_Power_Average_Window_Size cannot exceed this parameter value. Recommended value: 10 Set this parameter through ADD CELLSETUP, query it through LST CELL, and modify it through MOD CELLSETUP

322


z

DLPOWERAVERAGEWINDOWSIZE

Parameter name: DL power average window size

The recommended value is 20 time slots

FDDTPCDLSTEPSIZE

Parameter name: FDD DL power control step size

The recommended value is STEPSIZE_1DB, namely 1dB


z

Page60

DLPOWERAVERAGEWINDOWSIZE

Parameter name: DL power average window size

Value range: 1 to 60 time slots

Content: UTRAN calculates the increase of DL transmit power within the period defined via this parameter to determine whether the increase exceeds “Power Raise Limit”. If so, UTRAN will not increase the power even when it receives the command to raise the power


Set this parameter through ADD CELLSETUP, query it through LST CELL ,and modify it through MOD CELLSETUP

z

FDDTPCDLSTEPSIZE

Parameter name: FDD DL power control step size

Value range: STEPSIZE_0.5DB, STEPSIZE_1DB, STEPSIZE_1.5DB, STEPSIZE_2DB

Physical value range: 0.5, 1, 1.5, 2 dB

Content: The step size of the closed loop power control performed on DL DPCH in Frequency Division Duplex (FDD) mode.

Recommended value: STEPSIZE_1DB


323

Downlink Power Balance z

Purpose

Monitor the Tx power of NodeBs and start the DPB process

The purpose of this procedure is to balance the DL transmission powers of more than one Radio Links.

z

The start and stop of DPB

The power offset of two RLs is greater than the DPB start threshold, the DPB process is started

NodeB

NodeB

The power offset of two RLs is less than the DPB stop threshold, the DPB process is stopped


DPB process

Page61

z

During soft handover, the UL TPC is demodulated in each RLS, then due to demodulation errors, the DL transmit power of the each branch in soft handover will drift separately, which causes loss to the macro-diversity gain.

z

The DL Power Balance (DPB) algorithm is introduced to reduce the power drift between links during the soft handover.

324

Downlink Power Balance Parameters z

DOWNLINK_POWER_BALANCE_SWITCH


z

The default value is 0, namely OFF.

DPBSTARTTHD / DPBSTOPTHD

Parameter name: DPB start threshold / DPB stop threshold

The recommended value: DPB start threshold 8, namely 4dB; DPB stop threshold 4, namely 2dB.


z

z

Page62

DOWNLINK_POWER_BALANCE_SWITCH

This is one switch in PcSwitch (Power control algorithm switch) parameter.


Content: When it is checked, Downlink Power Balance (DPB) algorithm is applied to RNC. Downlink power drift among different RLs, which is caused by TPC bit error or other reasons, could reduce the gain of soft handover. DPB is mainly used to balance the downlink power of different RLs for an UE in order to achieve the best gain of soft handover.

Recommended value (default value): 0

Set this parameter through SET CORRMALGOSWITCH, query it through LST CORRMALGOSWITCH, and modify it through SET CORRMALGOSWITCH

DPBSTARTTHD / DPBSTOPTHD

Parameter name: DPB start threshold / DPB stop threshold

Value range: 0~255

Physical value range: 0~127.5dB; step: 0.5

Content: The threshold of start / stop DL power balancing in soft handover. When the difference of the power values of every two paths is greater / smaller than or equal to this threshold in soft handover, the RNC shall start / stop DL power balancing; otherwise, shall not.

The recommended value is DPB start threshold 8, namely 4dB; DPB stop threshold 4, namely 2dB;

Set this parameter through SET DPB, query it through LST DPB and modify it through SET DPB

325



Page63

326

Outer Loop Power Control z

Why we need outer loop power control?

Different curves correspond to different multi-path environment BLER

SIR


z

The reason of outer loop power control

z

Page64

The QoS which NAS provides to CN is BLER, not SIR

The relationship between inner loop power control and outer loop power control

SIRtar should be satisfied with the requirement of decoding correctly. But different multi-path radio environments request different SIR

Therefore, the outer loop power control can adjust the SIR to get a stable BLER in the changeable radio environment

327

Uplink Outer Loop Power Control

Measure BLER of received data and compare with the BLERtar

Measure SIR and compare with SIRtar

Out loop

Set BLERtar

Transmit TPC

Set SIRtar

RNC


z

Inner loop

NodeB

UE

Page65

Uplink outer-loop power control is performed in the SRNC. The SRNC measures the received BLER and compares it with the BLERtar. If the BLERmea is greater than the BLERtar, the SRNC increases the SIRtar; otherwise, the SRNC decreases the SIRtar.

328

Uplink Outer Loop Power Control z

SIRtar Adjustment

⎡ ⎤ BLER meas ,i ( n − 1 ) − BLER tar ,i SIRtar ( n ) = MAX ⎢ SIRtar ( n − 1 ) + × Step i × Factor ⎥ BLER tar ,i ⎣⎢ ⎦⎥

Where

i is the i:th transmission channel.

n is the n:th adjustment period.


z

Page66

According to the formula above,

SIRtar(n) is the target SIR used for the n:th adjustment period.

MAX means the maximum value among the total i transmission channels.

BLERmeas,i (n) is measured for the i:th transmission channel in the n:th adjustment period.

BLERtar,i is the target BLER of the i:th transmission channel.

Stepi is the adjustment step of the i:th transmission channel.

Factor is the adjustment factor.

329

Uplink Outer Loop Power Control Parameters z

OPLC_SWITCH


z

The default value is 1, namely ON

INITSIRTARGET

Parameter name: Initial SIR target value

The recommended value is shown in following table.


z

Page67

OPLC_SWITCH



Comments: When it is checked, RNC updates the uplink SIR TARGET of RLs on the NodeB side by Iub DCH FP signals

Default value: 1

Set this parameter through SET CORRMALGOSWITCH, query it through LST CORRMALGOSWITCH, and modify it through SET CORRMALGOSWITCH

z

INITSIRTARGET

Parameter name: Initial SIR target value


Physical value range: -8.2 to +17.3 dB, step 0.1

Content: Defining the initial SIR target value of outer loop power control.

Recommended value: refer to the following table.

Set this parameter through ADD TYPSRBOLPC / ADD TYPRABOLPC, query it through LST TYPSRB / LST TYPRAB, and modify it through MOD TYPSRBOLPC / MOD TYPRABOLPC

330


z

SIRADJUSTPERIOD

Parameter name: OLPC adjustment period


SIRADJUSTFACTOR

Parameter name: SIR adjustment coefficient

The recommended value is 10, namely 1


z

SIRADJUSTPERIOD

Parameter name: OLPC adjustment period.


Physical value range: 10 to 1000 ms, step 10

z

Page68

Comments: Outer loop power control varies with radio environment. A fast changing radio environment leads to a shorter outer loop power control adjustment period, while a slower changing one makes the period longer. Default value: 40 Set this parameter through ADD TYPSRBOLPC / ADD TYPRABOLPC, query it through LST TYPSRB / LST TYPRAB, and modify it through MOD TYPSRBOLPC / MOD TYPRABOLPC

SIRADJUSTFACTOR

Parameter name: SIR adjustment coefficient


Physical value range: 0.1 to 1 , step: 0.1

Content: It is used to adjust the best OLPC step for different cells when the OLPC algorithm is given. Recommended value: 10, namely 1 Set this parameter through SET OPLC / ADD CELLOLPC, query it through LST OPLC, and modify it through SET OPLC / MOD CELLOLPC

331


z

BLERQUALITY

Parameter name: Service DCH_BLER target value


SIRADJUSTSTEP

Parameter name: SIR adjustment step

The recommended value is shown in the following table.


z

SIRADJUSTSTEP

Parameter name: SIR adjustment step


Physical value range: 0 to 10 , step: 0.001dB

Content: Step of target SIR adjustment in outer loop power control algorithm.

z

Page69

Set this parameter through ADD TYPSRBOLPC / ADD TYPRABOLPC, query it through LST TYPSRB / LST TYPRAB ,and modify it through MOD TYPSRBOLPC / MOD TYPRABOLPC

BLERQUALITY

Parameter name: Service DCH_BLER target value


Physical value range: 5×10-7 to 1

Content: This QoS-related parameter is used by CRNC to decide the target SIR value that influences access and power control. Use the formula below to get the integer value of the parameter: 10×Log 10(BLER). Set this parameter through ADD TYPSRBOLPC / ADD TYPRABOLPC, query it through LST TYPSRB / LST TYPRAB, and modify it through MOD TYPSRBOLPC / MOD TYPRABOLPC

332


Referential configurations for typical services:

Service

SRB 3.4k

SRB 13.6k

AMR 12.2k

CSD 64k

PS I/B 8k

PS I/B 16k

PS I/B 32k

PS I/B 64k

PS I/B 128k

PS I/B 144k

PS I/B 256k

PS I/B 384k

SIR init target value

102

122

102

122

102

102

102

102

102

107

122

142

OLPC adjustment period

4

2

2

2

4

2

2

2

2

2

2

2

Service DCH_BLER target value

-20

-20

-20

-27

-20

-20

-20

-20

-20

-20

-20

-20

SIR adjustment step

4

10

5

2

4

4

4

4

4

4

4

4


z

Page70

Where,

CSD: CS domain Data service

I/B: Interactive and Background.

333

Uplink Outer Loop Power Control z

The parameters MaxSirStepUp and MaxSirStepDown limit the adjustment range of the SIRtar , and the algorithm is:

If ΔSIRtar > 0 and ΔSIRtar > “MaxSirStepUp” , then SIRtar (n+1) = SIRtar (n) + MaxSirStepUp

If ΔSIRtar < 0 and ABS( ΔSIRtar ) > “MaxSirStepDown” , then SIRtar (n+1) = SIRtar (n) – MaxSirStepDown

z

The parameters MaxSirtarget and MinSirtarget limit the range of the SIRtar at any time.


z

Page71

Where,

ΔSIRtar is the adjustment of SIRtar, and ΔSIRtar = SIRtar (n+1) - SIRtar (n)

ABS( ΔSIRtar ) means absolute value of ΔSIRtar

334


z

MAXSIRSTEPUP / MAXSIRSTEPDN

Parameter name: Maximum SIR increase / decrease step


MAXSIRTARGET / MINSIRTARGET

Parameter name: Maximum / Minimum SIR target



z

MAXSIRSTEPUP / MAXSIRSTEPDN

Parameter name: Maximum SIR increase / decrease step



z

Page72

Content: Maximum allowed SIR increase/ decrease step within an outer loop power control adjustment period. The recommended value is shown in following table. Set this parameter through ADD TYPSRBOLPC / ADD TYPRABOLPC, query it through LST TYPSRB / LST TYPRAB ,and modify it through MOD TYPSRBOLPC / MOD TYPRABOLPC

MAXSIRTARGET / MINSIRTARGET

Parameter name: Maximum / Minimum SIR target


Physical value range: -8.2 to17.3 dB, step: 0.1

Content: Define the maximum /minimum SIR target value of outer loop power control algorithm. The recommended value is shown in following table. Set this parameter through ADD TYPSRBOLPC / ADD TYPRABOLPC, query it through LST TYPSRB / LST TYPRAB ,and modify it through MOD TYPSRBOLPC / MOD TYPRABOLPC

335


Referential configurations for typical services:

Service

SRB 3.4k

SRB 13.6k

AMR 12.2k

CSD 64k

PS I/B 8k

PS I/B 16k

PS I/B 32k

PS I/B 64k

PS I/B 128k

PS I/B 144k

PS I/B 256k

PS I/B 384k

Maximum SIR increase step

400

500

500

1000

400

400

400

400

400

400

400

400

Maximum SIR decrease step

200

200

200

100

200

200

200

200

200

200

200

200

Maximum SIR target

132

132

132

152

132

132

132

132

132

137

152

172

Minimum SIR target

62

62

62

62

62

62

62

62

62

62

62

62


z

Page73

Where,

CSD: CS domain Data service

I/B: Interactive and Background.

336

Downlink Outer Loop Power Control Measure BLER of received data and compare with the BLERtar

L3

Outer loop set SIRtar

Inner loop

L1

NodeB

Transmit TPC

Measure SIR and compare with SIRtar

UE


Page74

z

The downlink outer loop power control is implemented inside the UE. Therefore, this algorithm is specified by UE manufacturer.

z

Generally, the UE L3 measures the received BLER and compares it with the BLERtar. If the BLERmea is greater than the BLERtar, the L3 increases the SIRtar and send it to UE L1; otherwise, the L3 decreases the SIRtar.

337

Summary z

In this course, we have discussed function, principle and common parameters of the following power control algorithm:

Open loop power control

Inner loop power control

Outer loop power control


Page75

338


339

WCDMA Handover Principle and Relevant Parameters www.huawei.com


66

Foreword z

Why mobile system need handover?

The mobility of UE

Load Balance

Any others ?


z

Page1

Handover is a basic function of a cellular mobile network. The purpose of handover is to ensure that a UE in CELL_DCH state is served continuously when it moves.

z

HCS: hierarchical cell structure

67

z

Handover types supported by UMTS

68

Objectives z


Know the features of each handover

Know the algorithms of handover

Know the handover procedure

Know the parameters of handover


z

Page3

Handover types supported by UMTS can be classified as:

Intra-frequency handover

Inter-frequency handover

Inter-RAT handover

69

The Basic Concepts of Handover z

Active Set

z

Maximum Ratio Combination

z

Monitored Set

z

Selective Combination

z

Detected Set

z

Soft Handover Gain

z

Radio Link (RL)

z

P-CPICH

z

Radio Link Set (RLS)


z

Page4

Active set : Cells, which belong to the active set. User information is sent from all these cells. In FDD, the cells in the active set are involved in soft handover. The UE shall only consider active set cells included in the variable CELL_INFO_LIST for measurement; i.e. active set cells not included in the CELL_INFO_LIST shall not be considered in any event evaluation and measurement reporting.

z

Monitored set :Cells, which are not included in the active set, but are included in the CELL_INFO_LIST belong to the monitored set.

z

Detected set : Cells detected by the UE, which are neither in the CELL_INFO_LIST nor in the active set belong to the detected set. Reporting of measurements of the detected set is only applicable to intra-frequency measurements made by UEs in CELL_DCH state.

z

RL: Radio link between NodeB and UE.

z

RLS: Radio link set. The RLs from same NodeB.

z

Combination way: For soft handover, the uplink signals are combined in RNC. The RNC will select one best signal to process. We call this selective combination. For softer handover, the uplink signals are combined in the RAKE receiver of NodeB. It is maximum ratio combination.

z

Soft handover gain: We have introduced in Coverage Planning.

z

CPICH: Common Pilot Channel. UE measure the signal strength of CPICH for handover decision.

70

Contents 1. Intra-Frequency Handover 2. Inter-Frequency Handover 3. Inter-RAT Handover


Page5

71

Contents 1. Intra-Frequency Handover 1. Intra-Frequency Handover Overview 2. Intra-Frequency Handover Procedure 3. Signaling Procedures for Intra-Frequency Handover


Page6

72

Intra-Frequency Handover Overview Characters of Intra-Frequency Handover: z

The carrier frequencies of the current cell and target cell are the same

Intra-frequency soft handover

Intra-frequency hard handover.


z

z

Page7

Intra-frequency handover consists of two types,

Intra-frequency soft handover: more than one radio link are set up for the UE.

Intra-frequency hard handover: only one radio link is set up for the UE.

Intra-frequency soft handover is more commonly used than intra-frequency hard handover. Intra-frequency hard handover is used only in some special scenarios, for example, when there is no Iur interface between two RNCs.

73

Intra-Frequency Handover Overview Comparison between soft handover and hard handover:

Item The number of RLs in

Soft Handover

Hard Handover

Several

One

No

Yes

Only happened

Can be happened in Intra-

between Intra-

frequency cells or Inter-frequency

frequency cells

cells

active set after handover Interruption during handover The frequencies of cells


z

Page8

The maximum number of RL is 3. This value can be changed. But this function need the UE to support. Normally, the active set supported by UE is fixed 3 and can not be changed.

74

Intra-Frequency Handover Overview Intra-Frequency Soft Handover : z

Soft Handover

z

Softer Handover


z

Page9

Intra-Frequency soft handover is a function in which the UE is connected to several cells at the same time. Addition or release of radio links are controlled by the ACTIVE SET UPDATE procedure.

z

During soft handover, a UE is in the overlapping cell coverage area of two sectors belonging to different base stations. The communications between UE and base station take place concurrently via two air interface channels from each base station separately.

z

During softer handover, a UE is in the overlapping cell coverage area of two adjacent sectors of a base station. The communications between UE and base station take place concurrently via two air interface channels, one for each sector separately.

75

Intra-Frequency Handover Overview Comparison between soft handover and softer handover : Item Scenario

Uplink

Softer Handover

Soft Handover

When the UE is in the overlapped

When the UE is in the overlapped

coverage area of two neighboring

coverage area of two neighboring

cells of a NodeB with combined RLs

cells of different NodeBs

Using maximum-ratio combination

Using selection combination



Occupying less Iub bandwidth

Occupying more Iub bandwidth

signal

Downlink signal Resource use


Page10

During softer handover, the uplink signaling are combined in NodeB by maximum ratio combination, but during soft handover they are combined in RNC by selective combination

Compare to later one, the maximum ratio combination can get more gain. So the performance of maximum ratio combination is better

Since softer handover is completed in NodeB, it do not consume transport resource of Iub

76

Intra-Frequency Handover Overview Intra-Frequency Hard Handover : z

No Iur interface

z

Iur interface is congested

z

High-speed Best Effort (BE) service Handover

z

Soft handover fails


z

Page11

Intra-frequency hard handover refers to a handover where all the old radio links are released before the new radio links are established. Compared with soft handover, intra-frequency hard handover uses fewer resources.

z

The scenarios of intra-frequency hard handover are as follows:

The UE needs to perform the intra-frequency handover between two cells configured in different RNCs. No Iur interface is present between RNCs.

The UE needs to perform the intra-frequency handover between two cells configured in different RNCs. The Iur interface is congested between RNCs.

There is a high-speed Best Effort (BE) service.

Compared with soft handover, intra-frequency hard handover is used to save downlink bandwidth for a high-speed BE service. The intra-frequency soft handover fails and intra-frequency hard handover is allowed. When intra-frequency soft handover fails because of a congestion problem of the

target cell, the RNC tries an intra-frequency hard handover with a lower service bit rate. The INTRA_FREQUENCY_HARD_HANDOVER_SWITCH parameter in the SET CORRMALGOSWITCH command is used to determine whether to enable intrafrequency hard handover. By default, this switch is ON. 77



Page12

78

Intra-Frequency Handover Procedure The following figure shows handover procedure

Measure the CPICH Ec/N0 of the serving cell and its neighboring cells as well as the relative time difference between the cells

Measurement

Measurement phase

Decision

No Are handover criteria satisfied?

Yes

Execution

Perform a handover and update relative parameters


z

Decision phase

Execution phase

Page13

Intra-frequency handover procedure is divided into three phases: handover measurement, handover decision, and handover execution.

z

After the UE transits to CELL_DCH state in connected mode during a call, the RNC sends a measurement control message to instruct the UE to take measurements and report the measurement event results.

z

Upon receiving an event report from the UE, the RNC makes a handover decision and performs the corresponding handover

79

Contents 1. Intra-Frequency Handover 1. Intra-Frequency Handover Overview 2. Intra-Frequency Handover Procedure 1. Intra-Frequency Handover Measurement 2. Intra-Frequency Handover Decision and Execution 3. Neighboring Cell Combination Algorithm

3. Signaling Procedures for Intra-Frequency Handover


Page14

80

Intra-Frequency Handover Measurement MEASUREMENT CONTROL

UE

UTRAN

MEASUREMENT CONTROL


Page15

z

The measurement control message carries the following information:

z

Event trigger threshold

z

Hysteresis value

z

Event trigger delay time

z

Neighboring cell list

81

Intra-Frequency Handover Measurement MEASUREMENT REPORT

UE

UTRAN

MEASUREMENT REPORT


Page16

The purpose of the measurement reporting procedure is to transfer measurement results from the UE to UTRAN. z

z

Based on the algorithm in measurement control, the UE will measure the

signal strength or quality and check if it meet the requirement of all event. If it meet the requirement of any event, UE will send the measurement report to UTRAN to trigger the handover. The most important information in the measurement are the PSC , the CPICH Ec/No of the target cell, and the triggered event.

82

Intra-Frequency Handover Measurement z

L3 Filtering for Intra-Frequency Handover

z

The value after L3 filtering procedure is calculated according to following formula: Fn = (1 - α) x Fn-1 + α x Mn

z

where

z

Fn is the new measurement value obtained after L3 filtering.

z

Fn-1 is the last measurement value obtained after L3 filtering.

z

Mn is the latest measurement value obtained from the physical layer.

z

α = 1/2(k/2) (k is set to Intra-freq meas L3 filter coeff)

z

When α is set to 1, that is, k = 0, no L3 filtering is performed.


Page17

z

A is measurement value at the physical layer

z

B is the measurement value after layer 1 filtering at physical layer. The value goes from the physical layer to high layer

z

C is measurement after processing in the layer3 filter

z

C’ is another measurement value

z

D is measurement report information sent on the radio interface or Iub interface

83

Key parameters of Intra-frequency Measurement z

z

Intra-freq Measure Quantity

Parameter ID: IntraFreqMeasQuantity

The default value of this parameter is CPICH_Ec/No

Intra-freq meas L3 filter coeff

Parameter ID: FilterCoef

The default value of this parameter is 3


Page18

The measurement quantity of intra-frequency handover can be Common Pilot Channel (CPICH) Ec/No or CPICH Received Signal Code Power (RSCP). It can be used in all the measurement events of intra-frequency handover zIntra-freq

Measure Quantity

Parameter ID: IntraFreqMeasQuantity

Value range: CPICH_Ec/No, CPICH_RSCP

Content: This parameter specifies the measurement quantity used in intrafrequency measurement.

The default value of this parameter is CPICH_Ec/No

Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

Before judging a measurement event and sending the measurement report, the UE performs L3 filtering for the measurement value. zIntra-freq

meas L3 filter coeff

Parameter ID: FilterCoef

Value range: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 13, 15, 17, 19

Content: This parameter specifies the intra-frequency measurement L3 filter coefficient. The greater this value is set, the greater the smoothing effect and the higher the anti-fast fading capability are, but the lower the signal change tracing capability is.



84

Intra-Frequency Handover Measurement Events Event 1A

Description The PCPICH quality or strength of the cells in the monitored set enters the reporting range . This indicates that the cell is close to the best cell . A relative high combined gain can be achieved when the cell is added to the active set

1B

The PCPICH quality or strength of the cells in the active set leaves the reporting range. This indicates that a cell is much worse than the quality of the best cell. The cell should not stay in the active set

1C

A non-active PCPICH becomes better than an active PCPICH. This indicates that the quality or strength of a cell is close to the best cell. In addition ,the number of cells in the active set has reached the maximum value. The cell replaces the worst cell in the active set ; thus achieving a higher combined gain

1D

Event of the change of the best cell

1J

RAN10.0 provides the solution to the issue of how to add an HSUPA cell in a DCH active set to an E-DCH active set. Event 1J is added to the 3GPP protocol. This event is triggered when a nonactive E-DCH but active DCH primary CPICH becomes better than an active E-DCH primary CPICH.

85

Intra-Frequency Handover Measurement 1A EVENT

z

Event 1A is triggered on the basis of the following formula

⎛ NA ⎞ M New + CIONew ≥ W ⎜⎜ ∑ M i ⎟⎟ + (1 − W ) M Best − ( R1a − H1a / 2) ⎝ i =1 ⎠


Page20

MNew is the measurement value of the cell in the reporting range.

CIONew is equal to the sum of Cell oriented Cell Individual Offset and Neighboring cell oriented CIO, which is the offset between the cell in the reporting range and the best cell in the active set.

W represents Weighted factor, used to weight the quality of the active set.

Mi is the measurement value of a cell in the active set.

NA is the number of cells not forbidden to affect the reporting range in the active set.

MBest is the measurement value of the best cell in the active set.

R1a is the reporting range or the relative threshold of soft handover. The threshold parameters of the CS non-VP service, VP service, and PS service are as follows:

CS non VP service 1A event relative THD

VP service 1A event relative THD

PS service 1A event relative threshold H1a represents 1A hysteresis, the hysteresis value of event 1A.

86

Intra-Frequency Handover Measurement 1A EVENT

A: signal curve of the best cell in the active set B: signal curve of a cell in the monitoring set C: Th1A curve Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

z

Page21

If the signal quality of a cell that is not in the active set is higher than Th1A for a period of time specified by 1A event trigger delay time (that is, Time to trigger in the figure), the UE reports event 1A

87

Parameters of Intra-Frequency Handover z

z

z


Parameter ID: IntraRelThdFor1ACSNVP

The default value of this parameter is 6 ( 3dB )


Parameter ID: IntraRelThdFor1ACSVP


PS service 1A event relative threshold

Parameter ID: IntraRelThdFor1APS



z

Page22


Parameter ID: IntraRelThdFor1ACSNVP

Value range: 0~14.5; step: 0.5

Content: This parameter specifies the relative threshold of event 1A for the CS non-VP service. The larger the parameter value is, the more easily event 1A is triggered..

The default value of this parameter is 6 (3dB)


z


Parameter ID: IntraRelThdFor1ACSVP


Content: This parameter specifies the relative threshold of event 1A for the VP service. The larger the parameter value is, the more easily event 1A is triggered..



z

PS service 1A event relative THD



Content: This parameter specifies the PS service relative threshold of event 1A. The smaller the parameter value is, the more easily event 1A is triggered.



88

Parameters of Intra-Frequency Handover Cell oriented Cell Individual Offset

z

Parameter ID: CIO

The default value of this parameter is 0 (0dB )

Neighboring cell oriented CIO

z

Parameter ID: CIOOffset



z

Page23

Cell oriented Cell Individual Offset

Parameter ID: CIO

Value range: -10

to +10

parameter is used together with Neighboring cell oriented CIO. The sum of the two parameter values is added to the measurement quantity before the UE evaluates whether an event occurred. In handover algorithms, this parameter is used for moving the border of a cell.

z

Content: This


Set this parameter through ADD

CELLSETUP/MOD CELLSETUP

Neighboring cell oriented CIO


Value range: -10

to +10

Content: This

parameter is used together with Cell oriented Cell Individual Offset. The sum of the two parameter values is added to the measurement quantity before the UE evaluates whether an event has occurred. In handover algorithms, this parameter is used for moving the border of 2 neighbors.


Set this parameter through ADD

INTRAFREQNCELL/MOD INTRAFREQNCELL

89


z

z

1A hysteresis

Parameter ID: Hystfor1A


1A event trigger delay time

Parameter ID: TrigTime1A

The default value of this parameter is D320 ( 320ms )

Weighted factor

Parameter ID: Weight



z

Page24

1A hysteresis Parameter ID: Hystfor1A Value range: 0~7.5; step: 0.5 Content: This parameter specifies the hysteresis value of event 1A. It is related to the slow fading characteristic. The default value of this parameter is 0 (0dB) Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

z

1A event trigger delay time Parameter ID: TrigTime1A Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms

Content: This parameter specifies the trigger delay time of event 1A. It is related to the slow fading characteristic. The greater the parameter value, the smaller the probability of misjudgment, but the slower the response of event reporting, triggered by measured signal changes.

The recommended value of this parameter is D320 ( 320ms )

Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO . zWeighted factor Parameter ID: Weight

Value range: 0~20,step:0.1

Content: This parameter is used to define the soft handover relative threshold based on the measured value of each cell in the active set. The greater the parameter value, the higher the soft handover relative threshold. When this value is set to 0, the soft handover relative threshold is determined only by the best cell in the active set. .

The Default Value of this parameter is 0 Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

90

Intra-Frequency Handover Measurement 1A Event Report Mode: z

Event Trigger Report

z

Event to Periodical Report


Page25

The report mode of 1A is Event Trigger Report . Generally the event 1A is reported only once. However, to avoid measurement report loss, the event 1A reporting can be turned to periodical reporting.

91

Parameters of Intra-Frequency Handover 1A event to periodical rpt period

z

Parameter ID: ReportIntervalfor1A

The default value of this parameter is D4000 (4000 ms )

1A event to periodical rpt number

z

Parameter ID: PeriodMRReportNumfor1A

The default value of this parameter is D16


z

Page26

1A event to periodical rpt period

Parameter ID: ReportIntervalfor1A

Value range: NON_PERIODIC_REPORT, D250, D500, D1000, D2000,

D4000, D8000, D16000

Content: The reporting period for the event 1A. Generally the event 1A is

reported only once. However, to avoid measurement report loss, the event 1A reporting can be turned to periodical reporting.

The default value of this parameter is D4000 (4000 ms)

Set this parameter through SET INTRAFREQHO/ADD

CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

z

1A event to periodical rpt number

Parameter ID: PeriodMRReportNumfor1A

Value range: D1, D2, D4, D8, D16, D32, D64, infinity

Content: The periodical reporting times for the event 1A. When the actual times exceed this parameter, the periodical reporting comes to an end.

The recommended value of this parameter is D16


92

Intra-Frequency Handover Measurement 1B EVENT

z

Event 1B is triggered on the basis of the following formula

M Old + CIOOld

⎛ NA ⎞ ≤ W ⎜⎜ ∑ M i ⎟⎟ + (1 − W ) M Best − ( R1b + H1b / 2), ⎝ i =1 ⎠


Page27

MOld is the measurement value of the cell that becomes worse.

CIOOld is equal to the sum of Cell oriented Cell Individual Offset and Neighboring cell oriented CIO, which is the offset between the cell in the reporting range and the best cell in the active set.

W represents Weighted factor, used to weight the quality of the active set.

Mi is the measurement value of the cell in the active set.

NA is the number of cells not forbidden to affect the reporting range in the active set. MBest is the measurement value of the best cell in the active set.

R1b is the reporting range or the relative threshold of soft handover. The threshold parameters of the CS non-VP service, VP service, and PS services are as follows:

CS non VP service 1B event relative THD

VP service 1B event relative THD

PS service 1B event relative threshold H1b represents 1B hysteresis, the hysteresis value of event 1B.

93

Intra-Frequency Handover Measurement 1B EVENT

A: signal curve of the best cell in the active set B: signal curve of a cell in the monitoring set C: Th1B curve


z

Page28

If the signal quality of a cell in the active set is lower than Th1B curve for a period of time specified by 1B event trigger delay time (Time to trigger in the figure), the UE reports event 1B

94

Parameters of Intra-Frequency Handover CS non VP service 1B event relative THD

z

Parameter ID: IntraRelThdFor1BCSNVP



z

Parameter ID: IntraRelThdFor1BCSVP


PS service 1B event relative threshold

z

Parameter ID: IntraRelThdFor1BPS



z

Page29

CS non VP service 1B event relative THD

Parameter ID: IntraRelThdFor1BCSNVP


Content: This parameter specifies the relative threshold of event 1B for the CS nonVP service. The smaller the parameter value is, the more easily event 1B is triggered .



z


Parameter ID: IntraRelThdFor1BCSVP


Content: This parameter specifies the relative threshold of event 1A for the VP service. The smaller the parameter value is, the more easily event 1B is triggered .



z

PS service 1A event relative THD



Content: This parameter specifies the PS service relative threshold of event 1A. The smaller the parameter value is, the more easily event 1B is triggered .



95

Parameters of Intra-Frequency

Handover

1B hysteresis

z

Parameter ID: Hystfor1B


1B event trigger delay time

z

Parameter ID: TrigTime1B



z

Page30

1B hysteresis



Content: This

parameter specifies the hysteresis value of event 1B. It is related to the slow fading characteristic.



z


Parameter ID: TrigTime1B

Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560,

5000 ms

Content: This

parameter specifies the trigger delay time of event 1B. It is related to the slow fading characteristic. The greater the parameter value, the smaller the probability of misjudgment, but the slower the response of event reporting, triggered by measured signal changes.

The recommended value of this parameter is D640 ( 640ms )

INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

Set this parameter through SET

96

Intra-Frequency Handover Measurement 1C EVENT

z

Event 1C is triggered on the basis of the following formula

M New + CIONew ≥ M InAS + CIOInAS + H1c / 2,


Page31

MNew is the measurement value of the cell in the reporting range.

CIONew is the cell individual offset value of the cell in the reporting range. It is equal to the sum of Cell oriented Cell Individual Offset and Neighboring cell oriented CIO, which is the offset between the cell in the reporting range and the best cell in the active set.

MInAS is the measurement value of the worst cell in the active set.

CIOInAS is the cell individual offset value of the worst cell in the active set. It is equal to the sum of Cell oriented Cell Individual Offset and Neighboring cell oriented CIO.

H1c represents 1C hysteresis, the hysteresis value of event 1C.

97

Intra-Frequency Handover Measurement 1C EVENT

A: signal curve of the best cell in the active set B: signal curve of a cell in the active set C: signal curve of the worst cell in the active set D: signal curve of a cell in the monitoring set E: Th1C curve Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

z

Page32

If the signal quality of a cell not in the active set is higher than Th1C for a period of time specified by 1C event trigger delay time (Time to trigger in the figure), the UE reports event 1C

98


z

1C hysteresis

Parameter ID: Hystfor1C


1C event trigger delay time

Parameter ID: TrigTime1C



Page33

1C hysteresis Parameter ID: Hystfor1C Value range: 0~7.5; step: 0.5 Content: This parameter specifies the hysteresis value of event 1C. It is related to the slow fading characteristic. The default value of this parameter is 8 (4dB) Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

z

1C event trigger delay time Parameter ID: TrigTime1C Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms Content: This parameter specifies the trigger delay time of event 1C. It is related to the slow fading characteristic. The greater the parameter value, the smaller the probability of misjudgment, but the slower the response of event reporting, triggered by measured signal changes. The recommended value of this parameter is D640 ( 640ms ) Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

z

99

Intra-Frequency Handover Measurement 1C Event Report Mode: z


z



Page34

The report mode of 1C is Event Trigger Report . Generally the event 1C is reported only once. However, to avoid measurement report loss, the event 1C reporting can be turned to periodical reporting.

100

Parameters of Intra-Frequency Handover 1C event to periodical rpt period

z

Parameter ID: ReportIntervalfor1C


1C event to periodical rpt number

z

Parameter ID: PeriodMRReportNumfor1C



z

Page35

1C event to periodical rpt period

Parameter ID: ReportIntervalfor1C

Value range: NON_PERIODIC_REPORT, D250, D500, D1000, D2000,

D4000, D8000, D16000

Content: The reporting period for the event 1C. Generally the event 1C is

reported only once. However, to avoid measurement report loss, the event 1C reporting can be turned to periodical reporting.



CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

z

1C event to periodical rpt number

Parameter ID: PeriodMRReportNumfor1C

Value range: D1, D2, D4, D8, D16, D32, D64, infinity

Content: The periodical reporting times for the event 1C. When the actual times exceed this parameter, the periodical reporting comes to an end.

The recommended value of this parameter is D16


101

Intra-Frequency Handover Measurement 1D EVENT

z

Event 1D is triggered on the basis of the following formula

M Notbest ≥ 10 M Best + H1d / 2,


Page36

MNotBest is the measurement value of a cell that is not in the list of the best cells.

MBest is the measurement value of the best cell in the active set.

H1d represents 1D hysteresis, the hysteresis value of event 1D.

102

Intra-Frequency Handover Measurement 1D Event

A: signal curve of the best cell in the active set B: signal curve of a cell in the active set or monitoring set C: Th1D curve


z

Page37

If the signal quality of a cell not in the active set is higher than Th1D for a period of time specified by 1D event trigger delay time (Time to trigger in the figure), the UE reports event 1D

103


z

1D hysteresis

Parameter ID: Hystfor1D


1D event trigger delay time

Parameter ID: TrigTime1D



Page38

1D hysteresis Parameter ID: Hystfor1D Value range: 0~7.5; step: 0.5 Content: This parameter specifies the hysteresis value of event 1D. It is related to the slow fading characteristic. The default value of this parameter is 8 (4dB) Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

z

1D event trigger delay time Parameter ID: TrigTime1D Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms Content: This parameter specifies the trigger delay time of event 1D. It is related to the slow fading characteristic. The greater the parameter value, the smaller the probability of misjudgment, but the slower the response of event reporting, triggered by measured signal changes. The recommended value of this parameter is D640 ( 640ms ) Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

z

104

Intra-Frequency Handover Measurement 1J EVENT

z

Event 1J is triggered on the basis of the following formula

M New + CIONew ≥ M InAS + CIOInAS + H1J / 2,


z

Page39

Reporting event 1J: A non-active E-DCH but active DCH primary CPICH becomes better than an active E-DCH primary CPICH

z

MNew is the measurement result of the cell not included in the E-DCH active set but included in DCH active set.

z

CIONew is the individual cell offset for the cell not included in the E-DCH active set but included in DCH active set becoming better than the cell in the E-DCH active set if an individual cell offset is stored for that cell. Otherwise, it equals 0.

z

MInAS is the measurement result of the cell in the E-DCH active set with the lowest measurement result.

z

CIOInAS is the individual cell offset for the cell in the E-DCH active set that is becoming worse than the new cell.

z

H1J is the hysteresis parameter for event 1J.

105

Intra-Frequency Handover Measurement 1J Event

A: signal quality curve of a cell in the E-DCH active set B: signal quality curve of the worst cell in the E-DCH active set C: signal quality curve of a cell not in the E-DCH active set but included in DCH active set D: signal quality curve of a cell not in the E-DCH active set but included in DCH active set In the figure, the hysteresis and the cell individual offsets for all cells equal 0 Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

Page40

z

The first measurement report is sent when primary CPICH D becomes better than primary CPICH B. The "cell measurement event result" of the measurement report contains the information of primary CPICH D and CPICH B.

z

On the assumption that the E-DCH active set has been updated after the first measurement report (E-DCH active set is now primary CPICH A and primary CPICH D), the second report is sent when primary CPICH C becomes better than primary CPICH A. The "cell measurement event result" of the second measurement report contains the information of primary CPICH C and primary CPICH A.

z

The parameters described in the following need to be set on the RNC LMT:

1J hysteresis

1J event trigger delay time

1J event to periodical rpt number

1J event to periodical rpt period

106


1J Event function

3GPP define the maximum DCH active set size is 6 and the maximum E-DCH active set size is 4

The DCH active set covers the E-DCH active set or they are the same

The best cell in E-DCH active set should be the same as that in DCH active set

Uplink channel type of UE is decided by the best cell in DCH active set

Uplink channel is E-DCH if the best cell in DCH active set supports HSUPA

Uplink channel is DCH if the best cell in DCH active set can NOT support HSUPA


Page41

107


Processing procedure for 1J Event

The UE reports 1J Event if it find a non-active E-DCH but active DCH cell PCICH becomes better than an active E-DCH PCIPCH

RNC will add the target cell into E-DCH active set if the E-DCH active set is NOT full

RNC will perform replace procedure if the E-DCH active set is full


Page42

108

Parameters of Intra-Frequency Handover 1J hysteresis

z

Parameter ID: Hystfor1J


1J event trigger delay time

z

Parameter ID: TrigTime1J


Max number of cell in edch active cell

z

Parameter ID: MAXEDCHCELLINACTIVESET



z1J

Page43

hysteresis

Parameter ID: Hystfor1J Value range: 0~7.5; step: 0.5 Content: This parameter specifies the hysteresis value of event 1J. It is related to the slow fading characteristic. The default value of this parameter is 8 (4dB) Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

z1J

event trigger delay time Parameter ID: TrigTime1J Value range: 0, 10, 20, 40, 60, 80, 100, 120, 160, 200, 240, 320, 640, 1280, 2560, 5000 ms Content: This parameter specifies the trigger delay time of event 1D. It is related to the slow fading characteristic. The recommended value of this parameter is D640 ( 640ms ) Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO .

zMax

number of cell in edch active cell Parameter ID: MAXEDCHCELLINACTIVESET Value range: 1 to 4 Content: This parameter specifies the maximum number of cells in the E-DCH active set. The recommended value of this parameter is 3 Set this parameter through SET HOCOMM .

109


z

1A Event Report Mode:



Parameters

1J event to periodical rpt period

Parameter ID: ReportIntervalfor1J


1J event to periodical rpt number

Parameter ID: PeriodMRReportNumfor1J



Page44

The report mode of 1J is Event Trigger Report . Generally the event 1J is reported only once. However, to avoid measurement report loss, the event 1J reporting can be turned to periodical reporting. z

1J event to periodical rpt period Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO

z

1J event to periodical rpt number Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD CELLINTRAFREQHO

110

Contents 1. Intra-Frequency Handover 1. Intra-Frequency Handover Overview 2. Intra-Frequency Handover Procedure 1. Intra-Frequency Handover Measurement 2. Intra-Frequency Handover Decision and Execution 3. Neighboring Cell Combination Algorithm



Page45

111

Intra-Frequency Handover Decision and Execution RNC will make decision and execute handover depends on the Events the RNC receives. z

1A Event

z

1B Event

z

1C Event

z

1D Event

z

1J Event


Event

Page46

Decision and Execution

1A

When receiving an event 1A report, the RNC decides whether to add a cell. For event 1A, the UE can report more than one cell in the event list in one measurement report. These cells are in the list of the Measurement Control message, and they are sequenced in descending order by measurement quantity. For the cells in the list, the RNC adds the radio link to the active set only if the number of cells in the active set does not reach the maximum value.

1B

When receiving an event 1B report, the RNC determines whether to delete a cell.

1C

When receiving an event 1C report, the RNC decides whether to change the worst cell. For event 1C, the UE reports a list that contains good cells and the cells to be replaced, and sequences the cells in descending order by measurement quantity. After receiving the list from the UE, the RNC replaces the bad cells in the active set with the good cells in the list.

112

When receiving an event 1D report, which includes information about only one cell, the RNC learns that the quality of this cell is better than that of the serving cell and takes one of the following actions: If the reported cell is in the active set, the RNC decides whether to change the best cell or reconfigure measurement control. If the reported cell is in the monitored set, If the number of cells in the active set has not reached the maximum value, the RNC decides a soft handover and adds the cell to the active set. If the number of cells in the active set has reached the maximum value, the RNC decides a soft handover and replaces the worst cell in the active set with the reported cell. The RNC determines whether the intra-frequency hard handover scenarios are applicable. For detailed information, see 3.1 Intra-Frequency Handover Types. If any scenario is applicable, the RNC performs an intra-frequency hard handover. •

•

•

1D

•

•

When receiving an event 1J report with information about the good cells and the cells to be replaced, the RNC proceeds as follows: If the current number of cells in the E-DCH active set is less than the value of Max number of cell in edch active set, the uplink of the cell where event 1J is triggered is reconfigured to E-DCH. If the current number of cells in the E-DCH active set is equal to the value of Max number of cell in edch active set, the RNC searches the measurement report for the non-serving Cell_EDCH with the lowest measured quality in the E-DCH active set. Then, the uplink of the cell where event 1J is triggered is reconfigured from DCH to E-DCH, and the uplink of CELL-EDCH is reconfigured from E-DCH to DCH. •

1J

•

113

Parameters of Intra-Frequency Handover When make decision, RNC must follow these restrictions z

z

Max number of cell in active set

Parameter ID: MaxCellInActiveSet


Minimum Quality Threshold for SHO

Parameter ID: SHOQualmin

The default value of this parameter is -24 ( -24dB)


Page48

Max number of cell in active set Parameter ID: MaxCellInActiveSet

z

Value range: 1~6; Content: This parameter specifies the Max number of cell in active set.

The default value of this parameter is 3 Set this parameter through SET INTRAFREQHO/ADD

CELLINTRAFREQHO/MOD CELLINTRAFREQHO . Minimum Quality Threshold for SHO

z

Parameter ID: SHOQualmin Value range: -24~0,step:1dB

Content: This parameter specifies the minimum quality threshold for soft handover.. The recommended value of this parameter is -24 (-24dB)


114

Rate Reduction After an SHO Failure z

For R99 NRT services to increase the probability of a successful soft handover, the rate reduction is triggered after a admission failure

1A,1C,1D is received by RNC

Execute admission control in target cell

Admission succeed? Rate Reduction

Execute Handover


Page49

If the RNC receives a 1A, 1C, or 1D measurement report, the corresponding cell tries to admit the UE. If the cell fails to admit the UE, the RNC performs the estimation procedure for rate reduction.

115

Rate Reduction After an SHO Failure

z

procedure for rate reduction

Estimation

Execution


Page50

116

z

Estimation Procedure for Rate Reduction

117

The estimation procedure after the cell fails to admit the UE is described as follows: z

Step 1 : The RNC evaluates whether the measurement quantity of the cell failing to be admitted meets the condition of rate reduction.

If the condition is met, the RNC performs a rate reduction process for the handover service immediately.

If the condition is not met, the RNC performs Step2.

z

The condition of rate reduction is as follows:

z

Mnew > Mbest_cell - RelThdForDwnGrd

z

where

z

Mnew is the CPICH Ec/No measurement value of the cell failing to be admitted. Mbest_cell is the CPICH Ec/No measurement value of the best cell in the active set. RelThdForDwnGrd is configured through the parameter Relative threshold of SHO failure.

Step 2 :The RNC evaluates whether the number of SHO failures in the cell exceeds the Threshold number of SHO failure.

If the number of SHO failures in the cell is smaller than the Threshold number of SHO failure, the RNC determines whether the SHO failure evaluation timer has been started:

If the timer has not been started, the RNC starts it. If the timer has been started, the RNC increments the SHO failure counter by one. Before the SHO failure evaluation timer expires, no action is taken and the RNC waits for the next measurement report period. When the SHO failure evaluation timer expires, the RNC sets the SHO failure counter of the corresponding cell to 0 and ends the evaluation.

z

If the number of SHO failures in the cell is larger than or equal to the Threshold number of SHO failure, the RNC performs a rate reduction process for the access service and sets the SHO failure counter of the corresponding cell to 0.

118


z

z

Relative threshold of SHO failure

Parameter ID: RelThdForDwnGrd


Max evaluation period of SHO failure

Parameter ID: ShoFailPeriod

The default value of this parameter is 60 ( 60s )

Threshold number of SHO failure

Parameter ID: ShoFailNumForDwnGrd



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Relative threshold of SHO failure Parameter ID: RelThdForDwnGrd Value range: -29 to +29 ; step: 0.5 dB Content: This parameter specifies the relative threshold for direct rate reduction after an SHO failure. If the difference between the signal quality of the target cell to which an SHO fails and that of the best cell is lower than this relative threshold, the RNC directly initiates a rate reduction process in the active set, regardless of the limitation on the number of SHO failures. The default value of this parameter is 2 (1dB) Set this parameter through SET INTRAFREQHO. Max evaluation period of SHO failure Parameter ID: ShoFailPeriod Value range: 0~120s Content: This parameter specifies the maximum evaluation period of SHO failures for rate reduction. During the evaluation period, the RNC records the number of SHO failures in at most three cells for each UE. After the evaluation period, the RNC clears this record. The recommended value of this parameter is 60 ( 60s ) Set this parameter through SET INTRAFREQHO zThreshold number of SHO failure Parameter ID: ShoFailNumForDwnGrd Value range: 0~63 Content: This parameter specifies the threshold number of SHO failures for rate reduction. If the number of SHO failures in a cell reaches or exceeds this threshold during the period specified by Max evaluation period of SHO failure, the RNC performs a rate reduction process in the active set. After the rate reduction succeeds, the RNC initiates an SHO in the cell. The recommended value of this parameter is 3 Set this parameter through SET INTRAFREQHO z

119

z

Execution Procedure of Rate Reduction

The rate reduction execution procedure is : z

Step1：The RNC performs a rate reduction process for the access service.

z

Step2：After the rate reduction succeeds, the RNC immediately attempts to add this cell to the active set without measurement:

If the cell succeeds in admitting the UE, the RNC adds the radio link and sets the SHO failure counter of the cell to 0 and ends the execution.

If the cell fails to admit the UE, the RNC starts the Period of penalty timer for SHO failure after down rate to avoid an increase in the rate triggered by DCCC within the period. Also in this period, the RNC sets the SHO failure counter of the cell to 0 and ends the execution. If fails to perform a soft handover again, RNC performs the

estimation procedure and the execution procedure, as previously described.

120

Parameters of Rate Reduction Execution z

Period of penalty timer for SHO failure after down rate

Parameter ID: DcccShoPenaltyTime

The default value of this parameter is 30 ( 30s )


z

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Period of penalty timer for SHO failure after down rate Parameter ID: DcccShoPenaltyTime Value range: 0 to 255 ; step: 1 s Content: If an SHO fails again after the rate reduction, the RNC is forbidden to increase the rate during the period specified by this parameter. The default value of this parameter is 30 ( 30s)

Set this parameter through SET INTRAFREQHO.

121

Contents 1. Intra-Frequency Handover 1. Intra-Frequency handover Overview 2. Intra-Frequency Handover Procedure 1. Intra-Frequency Handover Measurement 2. Intra-Frequency Handover Decision and Execution 3. Neighboring Cell Combination Algorithm



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122

Neighboring Cell Combination Algorithm z

When the UE is in soft handover state

z

The combined neighboring cell list is affect by :

Intra-frequency neighboring cells

Repeat times

Inter-frequency neighboring cells

Serving cell signal quality (Ec/No) order

Inter-RAT neighboring cells

Neighboring cell priority


z

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After obtaining the intra-frequency neighboring cells of each cell in the active set, the RNC calculates the union neighboring cell set of the intra-frequency cells, which is also referred as Sall, by using the following method. This method can also be used to generate the Sall of inter-frequency or inter-RAT cells. 1,The intra-frequency, inter-frequency and inter-RAT neighboring cells of each cell in the current active set are obtained. 2,The RNC sequences the cells in the active set in descending order of CPICH Ec/No according to the latest measurement report (event 1A, 1B, 1C, or 1D) from the UE. The best cell is based on event 1D, whereas other cells are based on the latest measurement report. 3,The cells in the active set are added to Sall. 4,The neighboring cells of the best cell in the active set are added to Sall. The priority of neighbor cell, which are set for each neighboring cell, are used to change the order of adding the neighboring cells to Sall. 5,The neighboring cells of other cells in the active set are added to Sall in descending order by CPICH Ec/No values of these cells in the active set. The neighboring cells of the same cell in the active set are added according to The priority of neighbor cell and repeated number of repeated neighboring cell is recorded. 6,If there are more than 32 neighboring cells in Sall, delete the neighboring cells whose repeat number in Sall is less. The top 32 neighboring cells are grouped into the final Sall.

If The flag of the priority is switched to FALSE, The priority of neighbor cell is cleared.

If The flag of the priority is switched to TRUE, The priority of neighbor cell is set simultaneously.

123

Parameters of Neighboring Cell Combination Algorithm Neighboring Cell Combination Switch

z

Parameter ID: NCELL_COMBINE_SWITCH

The default value of this parameter is OFF

The flag of the priority

z

Parameter ID: NPrioFlag

The default value of this parameter is FALSE

The priority of neighbor cell

z

Parameter ID: NPrio

The default value of this parameter is None


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The NCELL_COMBINE_SWITCH of Handover Algorithm Switch parameter decides the measurement range of neighboring cells If the switch is set to ON, measurement objects are chosen from the neighboring cells of all the cells in the active set.

If the switch is set to OFF, measurement objects are chosen from the neighboring cells of the best cell.

But, limited by the 3GPP, the maximum number of neighboring cells is 32. So if the NCELL_COMBINE_SWITCH is ON, it very possible that the neighboring cell of all the cells in the active set may exceed 32. By the Neighboring Cell Combination Algorithm , RNC will choose 32 neighboring cell for measurement. z

Neighboring Cell Combination Switch Parameter ID: NCELL_COMBINE_SWITCH Value range: OFF, ON Content: If the switch is set to ON, measurement objects are chosen from the neighboring cells of all the cells in the active set.If the switch is set to OFF, measurement objects are chosen from the neighboring cells of the best cell. The default value of this parameter is OFF Set this parameter through SET CORRMALGOSWITCH

124

z

The flag of the priority Parameter ID: NPrioFlag Value range: FALSE, TRUE Content: FALSE: The priority of the neighboring cell is invalid. The neighboring cells whose priority flag is FALSE are the last ones to be considered as the measurement objects in the neighboring cell combination algorithm. TRUE: The priority of the neighboring cell is valid in the neighboring cell combination algorithm. . The default value of this parameter is FALSE Set this parameter through ADD INTRAFREQNCELL/MOD INTRAFREQNCELL / ADD INTERFREQNCELL/MOD INTERFREQNCELL / ADD GSMNCELL/MOD GSMNCELL

z

The priority of neighbor cell Parameter ID: NPrio Value range: 0 to 30 The default value of this parameter is None Content: When The flag of the priority is TRUE, The priority of neighbor cell specifies the priority of neighboring cells. The smaller the parameter value is, the higher the priority is and the more easily the neighboring cell is chosen as a measurement object in the neighboring cell combination algorithm. For example, the neighboring cells with priority 1 are more easily chosen as the measurement objects than the cells with priority 2 in the neighboring cell combination algorithm.

z

Set this parameter through ADD INTRAFREQNCELL/MOD INTRAFREQNCELL / ADD INTERFREQNCELL/MOD INTERFREQNCELL / ADD GSMNCELL/MOD GSMNCELL

125



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126

Signaling Procedures for Intra-Frequency Handover There are five types of signaling procedures for intrafrequency handover: •

Intra-NodeB Intra-Frequency Soft Handover

•

Intra-RNC Inter-NodeB Intra-Frequency Soft Handover

•

Inter-RNC Intra-Frequency Soft Handover

•

Intra-RNC Inter-NodeB Intra-Frequency Hard Handover

•

Inter-RNC Intra-Frequency Hard Handover


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127

Signaling Procedures for Intra-Frequency Handover Intra-NodeB Intra-Frequency Soft Handover


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128

Signaling Procedures for Intra-Frequency Handover Intra-RNC Inter-NodeB Intra-Frequency Soft Handover


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129

Signaling Procedures for Intra-Frequency Handover Inter-RNC Intra-Frequency Soft Handover


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130

Signaling Procedures for Intra-Frequency Handover Intra-RNC Inter-NodeB Intra-Frequency Hard Handover


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131



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132

Contents 2. Inter-Frequency Handover z Inter-Frequency Handover Overview z Inter-Frequency Handover Procedure z Signaling Procedures for Inter-Frequency Handover


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133

Inter-Frequency Overview Characters of Inter-Frequency Handover: z

The carrier frequency of the current cell and target cell are different

z

Based on the triggering causes of handover, inter-frequency handover can be categorized into four types .

Coverage-based

QoS-based

Load-based

Speed-based


z

Coverage-based inter-frequency handover

z

According to the Link Stability Control Algorithm, the RNC needs to trigger the QoS-based inter-frequency handover to avoid call drops.

Load-based inter-frequency blind handover

z

If a moving UE leaves the coverage of the current frequency, the RNC needs to trigger the coverage-based inter-frequency handover to avoid call drops

QoS-based inter-frequency handover

z

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To balance the load between inter-frequency con-coverage cells, the RNC chooses some UEs and performs the inter-frequency blind handover according to user priorities and service priorities.

Speed-based inter-frequency handover

When the Hierarchical Cell Structure (HCS) applies, the cells are divided into different layers according to coverage. The macro cell has a larger coverage and a lower priority, whereas the micro cell has a smaller coverage and a higher priority. Inter-frequency handover can be triggered by the UE speed estimation algorithm of the HCS. To reduce the frequencies of handover, the UE at a higher speed is handed over to a cell under a larger coverage, whereas the UE at a lower speed is handed over to a cell under a smaller coverage.

134

Contents 2. Inter-Frequency Handover 1. Inter-Frequency Handover Overview 2. Inter-Frequency Handover Procedure 1. Coverage-based inter-frequency handover 2. QoS-based inter-frequency handover 3. Load-based inter-frequency handover 4. Speed-based inter-frequency handover 5. Blind handover Based on Event 1F 6. Inter-frequency anti-PingPong 7. Inter-frequency handover retry 3. Signaling Procedures for Inter-Frequency Handover


Page69

135

Procedure of Coverage-based inter-frequency handover

The handover procedure is divided into four phases: handover triggering, handover measurement, handover decision, and handover execution. z

In the triggering phase The RNC notifies the UE to measure through an inter-frequency measurement control message. If the quality of the pilot signal in the current cell deteriorates, the CPICH Ec/No or CPICH RSCP of the UMTS cell that the UE accesses is lower than the corresponding threshold, and the UE reports event 2D.

z

In the measurement phase If the RNC receives a report of event 2D, the RNC requests the NodeB and UE to start the compressed mode to measure the qualities of inter-frequency neighboring cells, and the RNC sends an inter-frequency measurement control message. In the measurement phase, the method of either periodical measurement report or eventtriggered measurement report can be used.

z

In the decision phase After the UE reports event 2B, the RNC performs the handover. Otherwise, the UE periodically generates measurement reports, and the RNC makes a decision after evaluation.

z

In the execution phase The RNC executes the handover procedure. 136

Coverage-based inter-frequency handover MEASUREMENT EVENTS Event 2D

Description

The estimated quality or strength of the currently used frequency is below a certain threshold.

2F

The estimated quality or strength of the currently used frequency is above a certain threshold.


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When the estimated quality or strength of the currently used frequency is below a certain threshold,2D

Event will be triggered, Then RNC will initiate the compress Mode to start interfrequency or inter-RAT handover measurement. During compress mode, if the the estimated quality of the currently used frequency is above a certain threshold, 2F

Event will be triggered, Then RNC will stop the compress Mode.

137

Coverage-based inter-frequency handover Compressed Mode z

Purpose

z

z

Measure the inter-frequency cell or Inter-RAT cell under FDD mode

Categories

Downlink compressed mode

Uplink compressed mode

Realization Methods

SF/2

Higher layer scheduling


z

Page72

Compressed Mode control is a mechanism whereby certain idle periods are created in radio frames during which the UE can perform measurements on other frequencies. The UE can carry out measurements in the neighbouring cell, such as GSM cell and FDD cell on other frequency. If the UE needs to measure the pilot signal strength of an inter-frequency WCDMA or GSM cell and has one frequency receiver only, the UE must use the compressed mode.

z

Each physical frame can provide 3 to 7 timeslots for the inter-frequency or inter-RAT cell measurement, which enhances the transmit capability of physical channels but reduces the volume of data traffic.

z

In DL, during compressed mode ,UE receiver can test signal from other frequency. In order to avoid the effect cause by UE transmitter, compress mode is also used in UL.

z

The compressed mode includes two types, spreading factor reduction (SF/2) and high layer approaches. The usage of type of compressed mode is decided by the RNC, according to spreading factor used in uplink or downlink.

138

Coverage-based inter-frequency handover 2D EVENT

z


QUsed <= TUsed2d - H2d/2


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QUsed is the measured quality of the used frequency. TUsed2d is the absolute quality threshold of the cell that uses the current frequency. Based on the service type (CS , PS domain R99 service, or PS domain HSPA service) and measurement quantity (CPICH Ec/No or RSCP), this threshold can be configured through one of the following parameters: Inter-freq CS measure start Ec/No THD Inter-freq R99 PS measure start Ec/No THD Inter-freq H measure start Ec/No THD Inter-freq CS measure start RSCP THD Inter-freq R99 PS measure start RSCP THD Inter-freq H measure start RSCP THD H2d is the event 2D hysteresis value 2D hysteresis.

After the conditions of event 2D are fulfilled and maintained until the parameter 2D event trigger delay time is reached, the UE reports the event 2D measurement report message.

Note: Any of the Ec/No and RSCP measurement result can trigger the 2D event.

139

Parameters of inter-frequency handover z

z

z

Inter-freq CS measure start Ec/No THD

Parameter ID: InterFreqCSThd2DEcNo

The default value of this parameter is -14dB

Inter-freq R99 PS measure start Ec/No THD

Parameter ID : InterFreqR99PsThd2DEcNo


Inter-freq H measure start Ec/No THD

Parameter ID : InterFreqHThd2DEcN0

The default value of this parameter is -14dB Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

z

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Value range: –24 to 0 ,step :1dB.


Content: If the CS service uses Ec/No as a measurement quantity, the UE reports event 2D when the measurement value is lower than the threshold. The RNC sends a message to enable the compressed mode and to start the inter-frequency measurement.

Set this parameter through ADD CELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SET INTERFREQHOCOV .

z



Value range: –24 to 0 ,step :1dB. The default value of this parameter is -14dB Content: If the PS domain R99 service uses Ec/No as a measurement quantity, the UE reports event 2D when the measurement value is lower than the threshold. The RNC sends a message to enable the compressed mode and to start the inter-frequency measurement. Set this parameter through ADD CELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SET INTERFREQHOCOV

z


Parameter ID : InterFreqHThd2DEcN0

Value range: –24 to 0 ,step :1dB. The default value of this parameter is -14dB Content: For PS domain HSPA services, when Ec/No is used as the measurement quantity for interfrequency measurement, the RNC sends the signaling to activate compressed mode and start interfrequency measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter. Set this parameter through ADD CELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SET INTERFREQHOCOV

140

Parameters of inter-frequency handover Inter-freq CS measure start RSCP THD

z


The default value of this parameter is -95dBm

Inter-freq R99 PS measure start RSCP THD

z

Parameter ID : InterFreqCSThd2DRSCP


Inter-freq H measure start RSCP THD

z

Parameter ID : InterFreqHThd2DRSCP

The default value of this parameter is -95dBm Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

z

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Inter-freq CS measure start RSCP THD


Value range: –115 to -25 dBm ,step :1dB.


Content: If the CS service uses RSCP as a measurement quantity, the UE reports event 2D when the measurement value is lower than the threshold. The RNC sends a message to enable the compressed mode and to start the inter-frequency measurement..


z





Content: If the PS domain R99 service uses RSCP as a measurement quantity, the UE reports event 2D when the measurement value is lower than the threshold. The RNC sends a message to enable the compressed mode and to start the inter-frequency measurement.

Set this parameter through ADD CELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SET INTERFREQHOCOV z


Parameter ID : InterFreqHThd2DRSCP



Content: For PS domain HSPA services, when RSCP is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to activate compressed mode and start inter-frequency measurement, if the UE reports the event 2D when the measured value is smaller than the value of this parameter .

Set this parameter through ADD CELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SET INTERFREQHOCOV

141

Parameters of inter-frequency handover 2D hysteresis

z




z

Parameter ID : TimeToTrig2D



z

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2D hysteresis


Value range: 0 to 29 step :0.5dB.


Content: This parameter specifies the event 2D trigger hysteresis, which is related to slow fading. The greater the value of this parameter, the smaller the probability of ping-pong effect and misjudgment. In this case, however, the event cannot be triggered in time.


z



Value range: D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320, D640, D1280, D2560, D5000 The default value of this parameter is D320 (320 ms)

Content: This parameter specifies the time of event 2D trigger delay, which is related to slow fading. The greater the value of this parameter, the smaller the probability of misjudgment. In this case, however, the event responds to the changes of measured signals at a lower speed. Set this parameter through ADD CELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SET INTERFREQHOCOV

142

Coverage-based inter-frequency handover z

2F EVENT Event 2F is triggered on the basis of the following formula

QUsed >= TUsed2d - H2d/2


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QUsed is the measured quality of the used frequency.

TUsed2f is the absolute quality threshold of the cell that uses the current frequency. Based on the service type (CS , PS domain R99 service or PS domain HSPA service) and measurement quantity (CPICH Ec/No or RSCP), this threshold can be configured through the following parameters:

Inter-freq CS measure stop Ec/No THD

Inter-freq R99 PS measure stop Ec/No THD

Inter-freq H measure stop Ec/No THD

Inter-freq CS measure stop RSCP THD

Inter-freq R99 PS measure stop RSCP THD

Inter-freq H measure stop RSCP THD H2f is the event 2F hysteresis value 2F hysteresis.

After the conditions of event 2F are fulfilled and maintained until the parameter 2F event trigger delay time is reached, the UE reports the event 2F measurement report message.

Note: Any of Ec/No and RSCP measurement result can trigger the 2F event.

143

Parameters of inter-frequency handover Inter-freq CS measure stop Ec/No THD

z

Parameter ID: InterFreqCSThd2FEcNo



z

Parameter ID : InterFreqR99PsThd2FEcNo



z

Parameter ID : InterFreqHThd2FEcN0

The default value of this parameter is -12dB Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

z

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Parameter ID: InterFreqCSThd2FEcNo



Content: If the CS service uses Ec/No as a measurement quantity, the UE reports event 2F when the measurement value is higher than the threshold. The RNC sends a message to disable the compressed mode and to stop the inter-frequency measurement.


z


Parameter ID : InterFreqR99PsThd2FEcNo



Content: If the PS domain R99 service uses Ec/No as a measurement quantity, the UE reports event 2F when the measurement value is higher than the threshold. The RNC sends a message to disable the compressed mode and to stop the inter-frequency measurement.



Parameter ID : InterFreqHThd2FEcN0



Content: For PS domain HSPA services, when Ec/No is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to deactivate compressed mode and stop inter-frequency measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter .

Set this parameter through ADD CELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SET INTERFREQHOCOV 144

Parameters of inter-frequency handover Inter-freq CS measure stop RSCP THD

z

Parameter ID: InterFreqCSThd2FRSCP

The default value of this parameter is -92 dBm


z

Parameter ID : InterFreqR99PsThd2FRSCP


Inter-freq H measure stop RSCP THD

z

Parameter ID : InterFreqHThd2FRSCP

The default value of this parameter is -92dBm Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

z

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Parameter ID: InterFreqCSThd2FRSCP


The default value of this parameter is -92 dBm

Content: If the CS service uses RSCP as a measurement quantity, the UE reports event 2F when the measurement value is higher than the threshold. The RNC sends a message to disable the compressed mode and to stop the inter-frequency measurement.


z


Parameter ID : InterFreqR99PsThd2FRSCP



Content: If the PS domain R99 service uses RSCP as a measurement quantity, the UE reports event 2F when the measurement value is higher than the threshold. The RNC sends a message to disable the compressed mode and to stop the inter-frequency measurement.


Inter-freq H measure stop RSCP THD

Parameter ID : InterFreqHThd2FRSCP



Content: For PS domain HSPA services, when RSCP is used as the measurement quantity for inter-frequency measurement, the RNC sends the signaling to deactivate compressed mode and stop inter-frequency measurement, if the UE reports the event 2F when the measured value is larger than the value of this parameter .


145

Parameters of inter-frequency handover 2F hysteresis

z

Parameter ID: Hystfor2F


2F event trigger delay time

z




z2F

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hysteresis

Parameter ID: Hystfor2F

Value range: 0 to 29 step :0.5dB.


Content: This parameter specifies the event 2F trigger hysteresis, which is related to slow fading. The greater the value of this parameter, the smaller the probability of ping-pong effect and misjudgment. In this case, however, the event cannot be triggered in time.

Set this parameter through ADD CELLINTERFREQHOCOV/MOD

CELLINTERFREQHOCOV/SET INTERFREQHOCOV

z2F

event trigger delay time


Value range: D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320, D640, D1280, D2560, D5000


Content: This parameter specifies the time of event 2F trigger delay, which

is related to slow fading. The greater the value of this parameter, the smaller the probability of misjudgment. In this case, however, the event responds to the changes of measured signals at a lower speed. Set this parameter through ADD CELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SET INTERFREQHOCOV

146

Coverage-based inter-frequency handover Handover Measurement

RNC

UE Measurement report

2D

Physical Channel Recfg (CM) Physical Channel Recfg Complet(CM) Measurement control (RSCP) Measurement control (Ec/No)


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When the UE enters the compress mode, RNC will trigger the inter-frequency handover measurement by two additional measurement control signaling , so as to request UE test inter-frequency neighbor cell. In this Measurement control message, RNC should inform the UE inter-frequency measurement parameter (Neighbor list, reporting mode…)

147


Handover Measurement

Report Mode RNC

UE

Measurement control (Periodical, RSCP&Ec/No)

RNC

UE

Measurement control (Event triggering, RSCP) Measurement control (Event triggering ,Ec/No)

Measurement report

Measurement report (2B RSCP or Ec/No)

Measurement report Measurement report

Handover

Handover

Periodical_reporting Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

Event_trigger

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The measurement report mode of inter-frequency handover is configured through the parameter Inter-frequency measure report mode. By default ,periodically reporting is recommended. The advantage of periodical measurement report is that if the handover fails, the RNC reattempts the handover to the same cell after receiving the periodical measurement report from the UE. This increases the probability of the success of inter-frequency handover. Based on the measurement control message received from the RNC, the UE periodically reports the measurement quality of the target cell. Then, based on the measurement report, the RNC makes the handover decision and performs handover.

148


z

z

Inter-frequency measure report mode

Parameter ID: InterFreqReportMode

The default value of this parameter is Periodical reporting

Inter-frequency measure periodical rpt period

Parameter ID: PeriodReportInterval


Inter-freq measure timer length

Parameter ID: InterFreqMeasTime

The default value of this parameter is 60 (60 s)


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Inter-frequency measure report mode Parameter ID: InterFreqReportMode Value range :Periodical reporting, Event trigger The default value of this parameter is Periodical reporting Content: This parameter specifies the inter-frequency measurement report mode. Set this parameter through ADD CELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SET INTERFREQHOCOV zInter-frequency measure periodical rpt period Parameter ID: PeriodReportInterval Value range : NON_PERIODIC_REPORT, 250, 500, 1000, 2000, 3000, 4000, 6000, 8000, 12000, 16000, 20000, 24000, 28000, 32000, 64000 The default value of this parameter is D500 (500ms) Content: This parameter specifies the interval of the inter-frequency measurement report. Set this parameter through ADD CELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SET INTERFREQHOCOV zInter-freq measure timer length Parameter ID: PeriodReportInterval Value range : 0 to 512 ,step 1s The default value of this parameter is 60 ( 60s) Content: This parameter specifies the inter-frequency measurement timer length of the interfrequency handover based on coverage or speed. This parameter has no effect on the interfrequency measurement based on QoS. If no such type of inter-frequency handover occurs upon expiry of the interfrequency measurement timer, the system stops the inter-frequency measurement and disables the compressed mode. If this parameter is set to 0, the RNC does not start the inter-frequency measurement timer. . Set this parameter for handover based on coverage through ADD CELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SET INTERFREQHOCOV z

149


Handover Measurement Event 2B is triggered on the basis of the following formula

QNoused >= TNoused2b + H2b/2

QUsed <= TUsed2b - H2b/2


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QNoused is the measured quality of the cell that uses the other frequencies. TNoused2b is the absolute quality threshold of the cell that uses the other frequencies. Based on the service type (CS , PS domain) and measurement quantity (CPICH Ec/No or RSCP), this threshold can be configured through the following parameters:

Inter-freq CS target frequency trigger Ec/No THD

Inter-freq R99 PS target frequency trigger Ec/No THD

Inter-freq CS target frequency trigger RSCP THD

Inter-freq R99 PS target frequency trigger RSCP THD

150

QUsed is the measured quality of the cell that uses the current frequency.

TUsed2b is the absolute quality threshold of the cell that uses the current frequency.

Based on the service type (CS service, PS domain service) and the measurement quantity (CPICH Ec/No or RSCP) in the coverage-based handover, TUsed2b can be configured through the following parameters.

If the event 2D with the CPICH RSCP value is received by the RNC,

TUsed2b of event 2B with the CPICH RSCP value can be: Inter-freq CS Used frequency trigger RSCP THD Inter-freq R99 PS Used frequency trigger RSCP THD

TUsed2b of event 2B with the CPICH Ec/No value is configured as the maximum value 0 dB according to 3GPP specification. If the event 2D with the CPICH Ec/No value is received by the RNC,

TUsed2b of event 2B with the CPICH Ec/No value can be： Inter-freq CS Used frequency trigger Ec/No THD Inter-freq R99 PS Used frequency trigger Ec/No THD

TUsed2b of event 2B with the CPICH RSCP value is configured as the maximum value -25 dB according to 3GPP specification. H2b is the event 2B hysteresis value 2B hysteresis.

151

Parameters of inter-frequency Handover Inter-freq CS target frequency trigger Ec/No THD

z

Parameter ID: TargetFreqCsThdEcN0

The default value of this parameter is –12 dB

Inter-freq CS Used frequency trigger Ec/No THD

z

Parameter ID: UsedFreqCSThdEcN0



z

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Inter-freq CS target frequency trigger Ec/No THD

Parameter ID: TargetFreqCsThdEcN0

Value range :–24 to 0, step 1dB


Content: If the CS service inter-frequency handover uses the event-triggered measurement report mode, event 2B may be triggered when the Ec/No value of the target frequency is higher than the threshold. In periodical measurement report mode, this parameter is used for handover evaluation on the RNC side.


z

Inter-freq CS Used frequency trigger Ec/No THD

Parameter ID: UsedFreqCSThdEcN0



Content: If the CS service inter-frequency handover uses the event-triggered measurement report mode, event 2B may be triggered when the Ec/No value of the used frequency is lower than the threshold.


z

Event 2B is triggered only when the two necessary conditions are met at the same time.

152


2B Event default setting Target cell

Used cell

CS Ec/No threshold -12dB

-12dB

PS Ec/No threshold

-12dB

-12dB

CS RSCP threshold -92dBm

-92dBm

PS RSCP threshold -92dBm

-92dBm


Page87

153

Parameters of inter-frequency handover 2B hysteresis

z




z

Parameter ID: TimeToTrig2B

The default value of this parameter is D0 (0ms)


z

Page88

2B hysteresis


Value range :0 to 29 , step 0.5dB


Content: This parameter specifies the event 2B trigger hysteresis, which is related to slow fading. The greater the value of this parameter, the smaller the probability of ping-pong effect and misjudgment. In this case, however, the event cannot be triggered in time.


z


Parameter ID: TimeToTrig2B

Value range D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320, D640, D1280, D2560, D5000


Content: This parameter specifies the time of event 2B trigger delay, which is related to slow fading. The greater the value of this parameter, the smaller the probability of misjudgment. In this case, however, the event responds to the changes of measured signals at a lower speed.


154

Coverage-based inter-frequency handover Handover Decision and Execution

Periodical Measurement Report Mode

Event-Triggered Measurement Report Mode


Page89

The coverage-based handover decision is categorized into two types according to the following two measurement report modes: periodical measurement report mode and event-triggered measurement report mode. Each mode corresponds to a different decision and execution procedure.

155

Coverage-based inter-frequency handover Handover Decision and Execution Event-Triggered Measurement Report Mode

Based on the event 2B measurement reports of CPICH RSCP and event 2B CPICH Ec/No of the inter-frequency cell


Page90

RNC process the report by following procedure:

Add all the pilot cells that trigger event 2B to a cell set and arrange the cells according to the measurement quality of CPICH_Ec/No in descending order.

Select the cells in turn from the cell set to perform inter-frequency handover.

156

Coverage-based inter-frequency handover Handover Decision and Execution Periodical Measurement Report Mode Both the CPICH Ec/No value and CPICH RSCP value of the pilot signal of the target cell must meet the requirement

Mother_Freq + CIOother_Freq ≥ Tother_Freq + H/2 NOTE: No consideration of the current cell


Page91

Mother_Freq is the CPICH Ec/No or CPICH RSCP measurement value of the target cell reported by the UE. Both of the two measurement values of the inter-frequency cell must satisfy the formula.

CIOother_Freq is the cell individual offset value of the target cell. It is equal to the sum of Cell oriented Cell Individual Offset and Neigbhoring cell oriented CIO.

Tother_Freq is the decision threshold of inter-frequency hard handover. Based on the service type (CS or PS service) and measurement quantity (CPICH

Ec/No or CPICH RSCP), this threshold can be configured through the following parameters: Inter-freq CS target frequency trigger Ec/No THD Inter-freq R99 PS target frequency trigger Ec/No THD Inter-freq H target frequency trigger Ec/No THD Inter-freq CS target frequency trigger RSCP THD Inter-freq R99 PS target frequency trigger RSCP THD Inter-freq H target frequency trigger RSCP THD

NOTE: These thresholds are the same as the quality threshold of event 2B.

H is the inter-frequency hard handover hysteresis value HHO hysteresis.

157

Coverage-based inter-frequency handover Handover Decision and Execution Periodical Measurement Report Mode


Page92

Decide whether both the CPICH Ec/No value and CPICH RSCP value of the pilot signal of the target cell meet the requirement of inter-frequency handover.

Start the hard handover time-to-trigger timer, which is configured through the parameter HHO period trigger delay time.

Select the cells in sequence, that is, from high quality cells to low quality ones, to initiate inter-frequency handover in the cells where the hard handover time-to-trigger timer expires.

158

Parameters of inter-frequency handover Cell oriented Cell Individual Offset

z

Parameter ID: CIO


Neigbhoring cell oriented CIO

z



HHO hysteresis

z

Parameter ID: HystForPrdInterFreq



zCell

Page93

oriented Cell Individual Offset

Parameter ID: CIO

Value range: -10 to +10

Content: This parameter is used together with Neighboring cell oriented CIO. The sum of the two parameter values is added to the measurement quantity before the UE evaluates whether an event occurred. In handover algorithms, this parameter is used for moving the border of a cell.


Set this parameter through ADD CELLSETUP/MOD CELLSETUP

zNeigbhoring

cell oriented CIO


Value range :–20 to +20 , step:0.5dB


Content: The sum of the value of this parameter and the Cell oriented Cell Individual Offset specifies the offset of the cell CPICH measurement value. In handover algorithms, this parameter is used for moving the border of a cell.


zHHO

hysteresis

Parameter ID: HystForPrdInterFreq

Value range 0 to 29 , step:0.5dB


Content: This parameter is used to evaluate the inter-frequency handover on the RNC side. The greater the value of the parameter, the smaller the probability of the ping-pong effect and misjudgment. In this case, however, the speed of response to handover is lower.


159



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160

Procedure of QoS-based inter-frequency handover :

The handover procedure is divided into four phases: handover triggering, handover measurement, handover decision, and handover execution. Besides the triggering step, the rest 3 steps are the same with Coverage-based inter-frequency handover z

In the triggering phase If the service quality of the current cell deteriorates, the Link Stability Control Algorithm makes a handover measurement decision.

z

In the measurement phase The RNC requests the NodeB and the UE to start the compressed mode to measure the qualities of interfrequency neighboring cells. Then, the RNC sends inter-frequency measurement control messages. In the measurement phase, the method of periodical measurement report or event-triggered measurement report can be used.

z

In the decision phase After receiving the event 2B measurement reports of CPICH RSCP and CPICH Ec/No of the interfrequency cell, the RNC performs the handover. Otherwise, the UE periodically generates measurement reports, and the RNC makes a decision after evaluation.

z

In the execution phase The RNC executes the handover procedure.

Note : About “Link Stability Control Algorithm” : When the uplink transmit power of the UE or downlink transmitted code power of the NodeB exceeds the associated threshold : z

For AMR, a fixed sequence of rate downsizing, inter-frequency handover, and then inter-RAT handover are performed,

z

for VP ,Inter-handover handover are performed,

z

For BE service, rate downsizing, inter-frequency handover, and then inter-RAT handover are performed according to the configured sequence

161

Parameters of inter-frequency handover

InterFreq Handover Switch based on Uplink Traffic AMR

z

Parameter ID: UlQoSAmrInterFreqHoSwitch

The default value of this parameter is NO

InterFreq Handover Switch based on Downlink Traffic AMR

z

Parameter ID: DlQoSAmrInterFreqHoSwitch



zInterFreq

Handover Switch based on Uplink/Downlink Traffic AMR

Parameter ID : UlQoSAmrInterFreqHoSwitch/

Page96

DlQoSAmrInterFreqHoSwitch

Value range NO, YES


Content: If the value of this parameter is YES, inter-frequency handover

can be executed on the basis of the downlink/uplink QoS of AMR services.

Set this parameter through SET QOSACT

162


InterFreq Handover Switch based on Uplink Traffic VP

z

Parameter ID: UlQoSVPInterFreqHoSwitch


InterFreq Handover Switch based on Downlink Traffic VP

z

Parameter ID: DlQoSVPInterFreqHoSwitch



zInterFreq

Handover Switch based on Uplink/Downlink Traffic VP

Parameter ID : UlQoSVPInterFreqHoSwitch/

Page97

DlQoSVPInterFreqHoSwitch

Value range NO, YES


Content: If the value of this parameter is YES, inter-frequency handover

can be executed on the basis of the downlink/uplink QoS of VP services.


163

Parameters of inter-frequency handover First / Second / Third Uplink QOS Enhancement Action for Traffic BE

z

Parameter ID: BeUlAct1/ BeUlAct2/ BeUlAct3

The default value of this parameter is RateDegrade/ InterFreqHO/ InterRatHO

First / Second / Third Downlink QOS Enhancement Action for Traffic BE

z

Parameter ID: BeDlAct1/ BeDlAct2/ BeDlAct3



z

Page98

First / Second / Third Uplink QOS Enhancement Action for Traffic BE

Parameter ID : BeUlAct1/ BeUlAct2/ BeUlAct3

Value range None, RateDegrade, InterFreqHO, InterRatHO


Content: This parameter defines the action sequence to enhance the

Uplink QoS of BE services .

z



Parameter ID : BeDlAct1/ BeDlAct2/ BeDlAct3



Content: This parameter defines the action sequence to enhance the

downlink QoS of BE services .


164


Down Link QoS Measure timer length

z

Parameter ID: DLQoSMcTimerLen

The default value of this parameter is 20 (20s)

Up Link QoS Measure timer length

z

Parameter ID: UpQoSMcTimerLen



z

Page99


Parameter ID : DLQoSMcTimerLen

Value range 0 to 512 ,step 1s


Content: This parameter specifies the inter-frequency measurement timer length of the interfrequency handover based on downlink QoS. This parameter has no effect on the interfrequency measurement based on coverage.

If no QoS-based inter-frequency handover occurs upon expiry of the downlink inter-frequency measurement timer, the RNC stops the QoS-based inter-frequency measurement. If this parameter is set to 0, the RNC does not start the inter-frequency QoS-based measurement timer. Set this parameter through ADD CELLQOSHO/MOD CELLQOSHO/SET QOSHO

z


Parameter ID : UpQoSMcTimerLen

Value range 0 to 512 ,step 1s


Content: This parameter specifies the inter-frequency measurement timer length of the interfrequency handover based on uplink QoS. This parameter has no effect on the interfrequency measurement based on coverage.

If no QoS-based inter-frequency handover occurs upon expiry of the uplink inter-frequency measurement timer, the RNC stops the inter-frequency measurement and disables the compressed mode. If this parameter is set to 0, the RNC does not start the inter-frequency QoS-based measurement timer. . Set this parameter through ADD CELLQOSHO/MOD CELLQOSHO/SET QOSHO

165



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166

Procedure of Load-based inter-frequency handover :

The handover procedure is divided into three phases: handover triggering, handover decision, and handover execution There is no measurement of the target cell, so we call it blind handover. z

In the triggering phase The Load Reshuffling (LDR) module directly determines whether the current cell is overloaded and whether an inter-frequency handover needs to be performed. The LDR module provides the target cell information for the current cell, and the RNC performs the handover procedure.

z

In the decision phase

The RNC decides to trigger an inter-frequency blind handover if If the blind handover neighbors are configured :

After the inter-frequency handover is triggered, the RNC chooses a decision algorithm according to whether the conditions “Blind handover condition” of direct blind handover are met.

If the value of the parameter of a cell is -115, the RNC performs direct blind handover to this cell. If there is no such cell with the parameter value -115, the RNC initiates an intra-frequency measurement for conditional blind handover. In the execution phase

z

The RNC performs the blind handover according to the decision result. 167

Load-based inter-frequency handover Handover triggering z

Target user

z

User with lower integrated priority

Target cell

Blind handover neighbor


Page102

Based on the service ARP, Traffic class, Channel type(R99, HSDPA), RNC will choose the users with lower priority to execute handover .

The target cell of this inter-frequency handover are only the blind handover neighbors with light load.which is indicated by the “Blind handover flag”

168

Parameters of inter-frequency handover Blind handover flag

z

Parameter ID: BlindHOFlag

The default value of this parameter is False


zCell

oriented Cell Individual Offset

Parameter ID : BlindHOFlag

Page103

Value range FALSE, TRUE


Content: This parameter indicates whether the neighboring cell is the

target cell for blind handovers. If the value is TRUE, blind handovers can be performed to the neighboring cell.

Set this parameter through ADD INTERFREQNCELL/MOD

INTERFREQNCELL

169

Load-based inter-frequency handover Handover Decision and Execution

z

The RNC determines to trigger an inter-frequency blind handover

z

RNC performs direct blind handover or conditional blind handover


Page104

After the RNC determines to trigger an inter-frequency blind handover ,according to the parameter Blind handover condition, the RNC executes:

If the value of the parameter of a cell is -115, the RNC performs direct blind handover to this cell.

If there is no such cell with the parameter value -115, the RNC initiates an intra-frequency measurement for conditional blind handover.

Note: If the neighboring cells have the same Blind handover condition value, the RNC chooses any one of them.

170

Load-based inter-frequency handover Handover Decision and Execution z

Conditional Blind Handover The inter-frequency cells with the same coverage area have the same CPICH RSCP values. By measuring the CPICH RSCP of the current cell, the quality of the cells with the same coverage area can be determined, which increases the probability of successful blind handover


Page105

The intra-frequency measurement for conditional blind handover is described as follows: 1.The RNC initializes the timer of intra-frequency measurement for blind handover. The timer is specified by internal algorithm and needn't to be configured. 2. The RNC modifies the measurement mode: The measurement reporting mode is changed to periodic reporting by a new measurement control . The reporting period is Intrafrequency measurement report interval of blind handover. The measurement reporting number is Intrafrequency measurement report amount of blind handover.The intrafrequency measurement quantity is CPICH RSCP. 3. After receiving from the UE the intra-frequency measurement reports for conditional blind handover, the RNC checks whether the following condition is met:

CPICH RSCP of the cell in the measurement report >= Blind handover condition

If the condition is met, the RNC increments the counter of the number of intrafrequency measurement reports for blind handover by 1. If the condition is not met, the RNC does not perform a blind handover to the cell that triggers LDR and stops intra-frequency measurement for blind handover. When the counter reaches the value of Intrafrequency measurement report amount of blind handover, the RNC initiates a blind handover to the cell that triggers LDR. If the counter does not reach this value, the RNC waits for the next intra-frequency measurement report from the UE. If the timer of intra-frequency measurement for blind handover expires, the RNC does not perform a blind handover to the cell that triggers LDR and stops intrafrequency handover for blind handover.

171

Parameters of inter-frequency handover Blind handover condition

z

Parameter ID: BlindHOQualityCondition

The default value of this parameter is -92 (-92dBm)

Intrafrequency measurement report interval of blind handover

z

Parameter ID: BlindHOIntrafreqMRInterval


Intrafrequency measurement report amount of blind handover

z

Parameter ID: BlindHOIntrafreqMRAmount



z

Page106

Blind handover condition

Parameter ID : BlindHOQualityCondition

Value range -115 to -25 , step:1dB


Content: This parameter specifies whether the cell supports a direct or conditional blind

handover. The value -115 indicates that the cell supports a direct blind handover. This value is usually used in configuration of inter-frequency cells with large coverage areas overlapped.

The other values indicate that the cell supports a conditional blind handover. This value is usually used in configuration of inter-frequency cells with some coverage areas overlapped.

z

Set this parameter through ADD INTERFREQNCELL/MOD INTERFREQNCELL

Intrafrequency measurement report interval of blind handover

Parameter ID: BlindHOIntrafreqMRInterval

Value range D250, D500


Content: This parameter specifies the intra-frequency measurement period for blind

handover. z

Set this parameter through SET INTRAFREQHO

Intrafrequency measurement report amount of blind handover

Parameter ID: BlindHOIntrafreqMRAmount

Value range D1, D2, D4, D8


Content: This parameter specifies the maximum number of intra-frequency measurement reports for blind handover

Set this parameter through SET INTRAFREQHO 172



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173

Procedure of Speed-based inter-frequency handover :

The handover procedure is divided into four phases: handover triggering, handover measurement handover decision, and handover execution z

In the triggering phase The RNC receives the internal handover request according to the HCS speed estimation. The handover based on HCS speed estimation is of two types: When the UE is in low-speed state, RNC will trigger handover from the macro cell to the micro cell. When the UE is in high-speed state, RNC will trigger handover from the micro cell to the macro cell. For different types of handover, the RNC acts differently.

z

z

In the measurement phase

If the handover is performed from a macro cell to a micro cell, the RNC triggers compressed mode ,then sends an inter-frequency measurement control message for 2C event to start the inter-frequency measurement procedure

If the handover is performed from a micro cell to a macro cell, the RNC directly performs blind handover, without measurement procedure. only if the handover fails, the RNC triggers compressed mode ,then sends an inter-frequency measurement control message for 2C event to start the inter-frequency measurement procedure

In the decision phase For handover from a macro cell to a micro cell, after the UE reports event 2C, the RNC performs the handover decision.

z

In the execution phase The RNC initiates a handover procedure.

If the handover is performed from a micro cell to a macro cell and the target cell of blind handover is configured, the RNC performs blind handover to the target cell.

If the blind handover fails or the handover is performed from a macro cell to a micro cell, the RNC performs the inter-frequency handover procedure to the cell with the best quality after receiving event 2C from the UE.

174

Speed-based inter-frequency handover MEASUREMENT EVENTS Event 2C

Description

The estimated quality of a non-used frequency is above a certain threshold.


Page109

Event 2C is only used in Speed-based inter-frequency handover. After

RNC believe the UE is in low-speed state, RNC will start handover from the macro

cell to the micro cell. RNC triggers compressed mode firstly, then sends an inter-frequency measurement control message for 2C event to start the inter-frequency measurement procedure.

175

Speed-based inter-frequency handover 2C EVENT

z


QNoused >= TNoused2c + H2c/2

2C only takes the Ec/No as the measurement quantity


Page110

QNoused is the measured quality of the cell that uses the other frequencies.

TNoused2c is the absolute quality threshold of the cell that uses the other frequencies, namely, Inter-freq measure target frequency trigger Ec/No THD.

H2c is the event 2C hysteresis value 2C hysteresis.

2C event trigger delay time is reached, the UE reports the event 2C measurement report message.

2C Event only takes the Ec/No as the measurement quantity.

176

Parameters of inter-frequency handover Inter-freq measure target frequency trigger Ec/No THD

z

Parameter ID: InterFreqNCovHOThdEcN0

The default value of this parameter is -16 (-16dB)

2C hysteresis

z




z




z

Page111

Inter-freq measure target frequency trigger Ec/No THD

Parameter ID : InterFreqNCovHOThdEcN0

Value range -24 to 0, step:1dB

The default value of this parameter is -16 (-16dB),

Content: When the Ec/No value of the target frequency is higher than the threshold, event 2C can be triggered

Set this parameter through ADD CELLINTERFREQHONCOV/MOD CELLINTERFREQHONCOV/SET INTERFREQHONCOV

z

2C hysteresis


Value range 0 to 29

The default value of this parameter is 6(3dB)

Content: This parameter specifies the event 2C trigger hysteresis, which is related to slow fading. The greater the value of this parameter, the smaller the probability of ping-pong effect and misjudgment. In this case, however, the event cannot be triggered in time.


z





Content: This parameter specifies the time of event 2C trigger delay, which is related to slow fading. The greater the value of this parameter, the smaller the probability of misjudgment. In this case, however, the event responds to the changes of measured signals at a lower speed.


177



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178

Blind handover Based on Event 1F Blind Handover z

Handover without measuring the neighboring cell

Load-based handover

Speed-based handover from micro cell to macro cell

1F event triggered inter-frequency handover


Page113

Blind handover is a special handover, means :before the handover, the UE needn’t report the target cell signal quality, RNC just select a target inter-frequency or interrat neighbor for the UE ,then force the UE handover to the target, the compressed mode and inter-frequency measurement can be overleaped The precondition of blind handover is :the blind handover neighbors are configured to a cell (Blind handover flag ), which is discussed in the forenamed slides. Blind handover may be triggered by load, UE speed and also the 1F event

179

Blind handover Based on Event 1F MEASUREMENT EVENTS Event 1F

Description

A Primary CPICH becomes worse than an absolute threshold.


Page114

1F Event is a intra-frequency measurement event, like 1A,1B,1C,1D. Events 1A,1B,1C,1D are used to trigger intra-frequency handover, Event 1F only trigger inter-frequency or inter-RAT blind handover.

180

Blind handover Based on Event 1F 1F EVENT

z

Event 1F is triggered on the basis of the following formula

MOld <= T1f - H1f/2


Page115

MOld is the measurement value of the cell that becomes worse.

T1f is an absolute threshold. It is set to 1F event absolute EcNo threshold or 1F event absolute RSCP threshold respectively, depending on the measurement quantity.

H1f is the event 1F hysteresis value 1F hysteresis.

After the conditions of event 1F are fulfilled and maintained until the 1F event trigger delay time is reached, the UE reports the event 1F measurement report message.

181

Parameters of inter-frequency handover 1F event absolute EcNo threshold

z

Parameter ID: IntraAblThdFor1FEcNo

The default value of this parameter is -24 (-24dB)

1F event absolute RSCP threshold

z

Parameter ID: IntraAblThdFor1FRSCP



z

Page116

1F event absolute EcNo threshold

Parameter ID : IntraAblThdFor1FEcNo

Value range -24 to 0, step:1dB

The default value of this parameter is -24 (-24dB),

Content: This parameter specifies the absolute EcNo threshold of event 1F. The

greater the parameter value is, the more easily event 1F is triggered. The smaller the parameter value is, the harder event 1F is triggered.


CELLINTRAFREQHO/MOD CELLINTRAFREQHO

1F event absolute RSCP threshold •Parameter ID: IntraAblThdFor1FRSCP

Value range -115 to -25 step:1dB

The default value of this parameter is -115(-115dBm)

Content: This parameter specifies the absolute RSCP threshold of event 1F. The

greater the parameter value is, the more easily event 1F is triggered. The smaller the parameter value is, the harder event 1F is triggered.


182

Parameters of inter-frequency handover 1F hysteresis

z

Parameter ID: HystFor1F



z

Parameter ID: TrigTime1F



z

Page117

1F hysteresis

Parameter ID : HystFor1F

Value range 0 to 15, step:0.5dB

The default value of this parameter is 8 (4dB),

Content: This parameter specifies the hysteresis value of event 1D. It is related to the slow fading characteristic. The greater the parameter value is, the smaller the probability of pingpong effect and misjudgment. In this case, however, the event cannot be triggered in time.

Set this parameter through SET INTRAFREQHO/ADD CELLINTRAFREQHO/MOD

CELLINTRAFREQHO

•1F event trigger delay time •Parameter ID: TrigTime1F



Content: This parameter specifies the trigger delay time of event 1F. It is related to the slow

fading characteristic. The greater the parameter value is, the smaller the misjudgment probability, but the slower the response of the event to the measured signal changes.


183



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184

Inter-frequency Anti-PingPong z

The inter-frequency anti-ping-pong algorithm is as follows:

Step1-When a coverage-based inter-frequency handover or an inter-frequency blind handover based on event 1F occurs, the RNC starts the timer specified by The timer length of anti ping-pong NCOV interfreq handover for the UE

Step2-When a non-coverage-based inter-frequency handover is triggered, first, the RNC determines whether the timer specified by The timer length of anti ping-pong NCOV interfreq handover expires

z

If the timer does not expire, the RNC cancels the handover

If the timer expires, the RNC performs the handover

Parameters

The timer length of anti pingpong NCOV interfreq handover

Parameter ID: 1FAntiPingPongtimerLength

The default value of this parameter is 30s


z

Page119

The timer length of anti pingpong NCOV interfreq handover

Parameter ID :IFAntiPingpangTimerLength

Value range:0~120

Physical unit:s

Content: the length of anti non-coverage based inter-frequency pingpong handover timer.

Recommended value:30 Set this parameter through SET HOCOMM

185



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186

Inter-frequency handover retry z

z

If an inter-frequency handover based on event-triggered measurement report mode fails, the RNC initiates the inter-frequency handover attempt according to an inter-frequency retry algorithm After the inter-frequency handover fails, the retry timer for the cell is started. After the retry timer expires, the UE makes a handover attempt to the cell again until the retry number exceeds the maximum allowed retry number. If the handover succeeds or two new event 2B reports are received, the periodical retry is stopped.

Handover is failed

Retry condition is satisfied?

2B event?

Start timer

END

Timer is expired

Trigger handover 2B measurement control is re-transmitted

implementation

z

For the inter-frequency handover based on coverage or QoS, the following two parameters determine the retry period and the maximum number of retry times:

z

2B event retry period

2B event retry max times

For the inter-frequency handover based on speed, the following two parameters determine the retry period and the maximum number of retry times:

2C event retry period

2C event retry max times

187

Inter-frequency handover retry z

Parameters


Parameter ID: PeriodFor2B

The default value of this parameter is 500ms


Parameter ID: AmntOfRpt2B

The default value of this parameter is 63 (infinity)


Parameter ID: PeriodFor2C

The default value of this parameter is 2s


Parameter ID: AmntOfRpt2C



z


z


Page122

Set above parameters through SET INTRERFREQHOCOV / ADD CELLINTERFREQHOCOV / MOD CELLINTERFREQHOCOV

z


z


Set above parameters through SET INTRERFREQHONCOV / ADD CELLINTERFREQHONCOV / MOD CELLINTERFREQHONCOV

188

Contents 2. Inter-Frequency Handover 1. Inter-Frequency Handover Overview 2. Inter-Frequency Handover Procedure 3. Signaling Procedures for Inter-Frequency Handover


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189

Intra-RNC Inter-Frequency Handover

190

Inter-RNC Inter-Frequency Handover

191



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192

Contents 3. Inter-RAT Handover 1. Inter-RAT Handover Overview 2. Inter-RAT Handover Procedure 3. Signaling Procedures for Inter-RAT Handover


Page127

193

Inter-RAT Handover Overview Inter-RAT Handover Application Scenario


z

Page128

Inter-RAT handover provides coverage expansion, load sharing, and layered services. It saves cost by utilizing the existing GSM network resources.

z

Inter-RAT handover refers to the handover between UMTS and GSM. The reason for the handover can be coverage limitation, link stability control or load limitation of the 3G system.

z

Inter-RAT handover can be UMTS-to-GSM or GSM-to-UMTS handover.

z

Strategy of 2G and 3G cooperation is shown in the picture:

Based on coverage, QoS , Service, load and speed, RNC can trigger UE handover from 3G to 2G; When UE return back to Idle Mode, trigger UE Cell reselect to 3G.

z

In this handover, however, GSM and UMTS dual-mode UEs (MSs) are required, and both the GSM MSC and the GSM BSS must be upgraded.

194

Inter-RAT Handover Overview Classification of Inter-RAT Handover: z

Based on the triggering causes of handover, inter-frequency handover can be categorized into four types .

Coverage-based

QoS-based

Load-based

Service-based

Speed-based


z

Coverage-based inter-frequency handover

z

If the load of the UMTS is heavy and all the RAB of a UE are supported by the GSM, the load-based UMTS-to-GSM handover is triggered.

Service-based UMTS-to-GSM handover

z

According to the Link Stability Control Algorithm, the RNC needs to trigger the QoSbased UMTS-to-GSM handover to avoid call drops.

Load-based inter-frequency blind handover

z

The coverage of the UMTS is incontinuous at the initial stage of the 3G network. On the border of the coverage, the poor signal quality of UMTS triggers the UMTS-to-GSM measurement. If the signal quality of GSM is good enough and all the services of the UE are supported by the GSM, the coverage-based UMTS-to-GSM handover is triggered.

QoS-based inter-frequency handover

z

Page129

Based on layered services, the traffic of different classes is handed over to different systems. For example, when an Adaptive Multi Rate (AMR) speech service is requested, this service can be handed over to the GSM.

Speed-based inter-frequency handover

When the Hierarchical Cell Structure (HCS) is used, the cells are divided into different layers on the basis of coverage. Typically, a marco cell has large coverage and low priority, whereas a micro cell has small coverage and high priority.UMTS-to-GSM handover can be triggered by the UE speed estimation algorithm of the HCS. A UE moving at high speed is handed over to a cell with larger coverage to reduce the times of handover, whereas a UE moving at low speed is handed over to a cell with smaller coverage.

195

Inter-RAT Handover Overview Preconditions for UMTS-to-GSM Handover : z

Service Handover Indicator

z

Capabilities of Deciding UMTS-to-GSM Handover

GSM neighboring cell capability

service capability

UE capability


Page130

z

Before handover, the RNC checks whether the preconditions meet the triggering requirements of the UMTS-to-GSM handover. The preconditions include the service handover indicator, GSM cell capability, service capability, and UE capability.

z

The parameter Service handover indicator indicates the CN policy for the service handover to the GSM. This parameter is indicated in the Radio Access Bearer (RAB) assignment signaling assigned by the CN, or can be configured on the RNC side by ADD/MOD TYPRABBASIC .

z

Before deciding UMTS-to-GSM handover, the RNC considers GSM cell capability, service capability and UE capability.

GSM cell capability could be “GSM”,”GPRS”,”EDGE”, it should be the real capability of the GSM neighbor, and configured in RNC data base by LMT correctly

Service capability could be “GSM”,”GPRS”,”EDGE” also, it should be properly configured in RNC data base by LMT

UE capability is reported by the UE itself in “RRC Setup Complete” message.

196


Service Handover Indicator

HO_TO_GSM_SHOULD_BE_PERFORM

HO_TO_GSM_SHOULD_NOT_BE_PERFORM

HO_TO_GSM_SHALL_NOT_BE_PERFORM

Example of rules for indicator of UMTS-to-GSM handover based on load and service


Page131

Before handover, the RNC checks service handover indicator, This parameter is indicated in the Radio Access Bearer (RAB) assignment signaling assigned by the CNThe service handover indicators are as follows:

HO_TO_GSM_SHOULD_BE_PERFORM: means that the handover to the 2G network is performed when 2G signals are available. HO_TO_GSM_SHOULD_NOT_BE_PERFORM: means that the handover to the 2G network is performed when 3G signals are weak but 2G signals are strong. HO_TO_GSM_SHALL_NOT_BE_PERFORM: means that the handover to the 2G network is not performed even when 3G signals are weak but 2G signals are strong.

197

z

For the UE accessing combined services (with CS services), the RNC sets the service handover indicator of the UE to that of the CS service, because the CS service has the highest QoS priority.

z

For the UE accessing combined services (with only PS services), the RNC sets the service handover indicator of the UE to that of the PS service, which has the highest QoS priority.

z

If service handover indicators are not configured by the CN, each indictor can be set to Service parameter index of a service on the RNC.

z

Based on different service handover indicators .RNC may initiate different action, for example, handover based on service are not not performed for the services whose handover indicator is “HO_TO_GSM_SHOULD_NOT_BE_PERFORM” or “HO_TO_GSM_SHALL_NOT_BE_PERFORM”

198


Capabilities of Deciding UMTS-to-GSM Handover

GSM neighboring cell capability NO_CAPABILITY, GSM, GPRS, EDGE

Service required capability GSM, GPRS, EDGE

UE capability GSM, GPRS, or EDGE

Note: For Service-Based UMTS-to-GSM Handover, there is an additional switch on RNC


Page133

The rules for enabling UMTS-to-GSM handover are based on the parameter Service Handover Indicator and the three types of capability parameters. The rules vary with different types of inter-RAT handover , that is , the 4 factors will decide if the inter-RAT handover is allowed. The rules are: z

Coverage-based and QoS-based UMTS-to-GSM handover

when Service Handover Indicator is set as follows:



In addition, the RNC initiates inter-RAT handover based on the following capabilities:

GSM cell capability (can be set on RNC)

Service required capability (can be set on RNC)

UE capability (reported from UE “RRC setup complete” message )

199

GSM neighboring cell with EDGE capability Service capability (required by 2G) UE Capability EDGE

GPRS

GSM

EDGE

Allowed

Allowed

Allowed

GPRS

Allowed

Allowed

Allowed

GSM

Not allowed

Not allowed

Allowed

Not supported by 2G

Not allowed

Not allowed

Not allowed

GSM neighboring cell with GPRS capability Service capability (required by 2G) UE Capability EDGE

GPRS

GSM

EDGE

Allowed

Allowed

Allowed

GPRS

Allowed

Allowed

Allowed

GSM

Not allowed

Not allowed

Allowed

Not supported by 2G

Not allowed

Not allowed

Not allowed

GSM neighboring cell with GSM capability Service capability (required by 2G) UE Capability EDGE

GPRS

GSM

EDGE

Not allowed

Not allowed

Allowed

GPRS

Not allowed

Not allowed

Allowed

GSM

Not allowed

Not allowed

Allowed

Not supported by 2G

Not allowed

Not allowed

Not allowed

If the capability of all the GSM neighboring cells is "No capability", the inter-RAT handover cannot be started. 200

z

load-based UMTS-to-GSM handover

z




service-based UMTS-to-GSM handover


HO_TO_GSM_SHOULD_BE_PERFORM The following switch are on:

Inter-RAT CS handover switch (service based)

Inter-RAT PS handover switch (service based)

In addition, the RNC initiates inter-RAT handover based on the following capabilities:

GSM cell capability (can be set on RNC)

Service required capability (can be set on RNC)

UE capability (reported from UE “RRC setup complete” message )

GSM neighboring cell with EDGE capability Service capability (required by 2G) UE Capability

EDGE GPRS GSM Not supported by 2G

EDGE

GPRS

GSM

Allowed

Allowed

Allowed

Not allowed

Allowed

Allowed

Not allowed

Not allowed

Allowed

Not allowed

Not allowed

Not allowed

201

GSM neighboring cell with GPRS capability Service capability (required by 2G) UE Capability

EDGE

GPRS

GSM

EDGE

Not allowed

Allowed

Allowed

GPRS

Not allowed

Allowed

Allowed

GSM

Not allowed

Not allowed

Allowed

Not supported by 2G

Not allowed

Not allowed

Not allowed

GSM neighboring cell with GSM capability Service capability (required by 2G) UE Capability

EDGE

GPRS

GSM

EDGE

Not allowed

Not allowed

Allowed

GPRS

Not allowed

Not allowed

Allowed

GSM

Not allowed

Not allowed

Allowed

Not supported by 2G

Not allowed

Not allowed

Not allowed

If the capability of all the GSM neighboring cells is "No capability", the inter-RAT handover cannot be started.

202

Inter-RAT Handover Overview z

Inter-RAT Handover RNC Algorithm Switch INTER_RAT_PS_OUT_SWITCH

Default value is ON

INTER_RAT_CS_OUT_SWITCH

Default value is ON


Page137

These switches are the parameter values of Handover algorithm switch in the command SET CORRMALGOSWITCH.

INTER_RAT_PS_OUT_SWITCH

The switch decides whether the RNC will initiate inter-RAT measurement to trigger inter-RAT handover of the PS domain from the UTRAN.

INTER_RAT_CS_OUT_SWITCH

The switch decides whether the RNC will initiate inter-RAT measurement to trigger inter-RAT handover of the CS domain from the UTRAN.

Set this parameter through SET CORRMALGOSWITCH

203

Contents 3. Inter-RAT Handover 1. Inter-RAT Handover Overview 2. Inter-RAT Handover Procedure 1. Coverage-based inter-RAT handover 2. QoS-based inter-RAT handover 3. Load-based inter-RAT handover 4. Service-based inter-RAT handover 5. UMTS-to-GSM Multimedia Fallback 6. PS UMTS-to-GSM Handover with NACC 7. UMTS-to-GSM Handover retry

3. Signaling Procedures for Inter-RAT Handover


Page138

204

Coverage-based inter-RAT handover


Page139

The handover procedure is divided into four phases: handover triggering, handover measurement, handover decision, and handover execution. z

In the triggering phase The RNC sends a MEASUREEMNT CONTROL message to the UE, notifying the UE to measure the current carrier quality. This message defines the reporting rules and thresholds of events 2D and 2F. If the quality of the pilot signal in the current cell deteriorates, the CPICH Ec/No or CPICH RSCP of the UMTS cell that the UE accesses is lower than the corresponding threshold and the UE reports event 2D.

z

In the measurement phase If the RNC receives a report of event 2D, the RNC may request the NodeB and UE to start the compressed mode to measure the qualities of GSM cells. Then, the RNC may send an interRAT measurement control message that defines the neighboring cell information, reporting period, and reporting rule. In the measurement phase, either periodical measurement report mode or event-triggered measurement report mode can be used.

z

In the decision phase After the UE reports event 3A, the RNC makes a handover decision. Or, after the UE periodically sends the measurement reports, the RNC evaluates the reports first and then makes a handover decision.

z

In the execution phase The RNC initiates a handover procedure. 205

Coverage-based inter-RAT handover MEASUREMENT EVENTS Event 2D

Description

The estimated quality of the currently used frequency is below a certain threshold.

2F

The estimated quality of the currently used frequency is above a certain threshold.


Page140

When the estimated quality of the currently used frequency is below a certain threshold,2D Event will be triggered, Then RNC will initiate the compress Mode to start inter-frequency or interRAT handover measurement. During compress mode, if the the estimated quality of the currently used frequency is above a certain threshold, 2F Event will be triggered, Then RNC will stop the compress Mode.

206

Coverage-based inter-RAT handover 2D EVENT

z


QUsed <= TUsed2d - H2d/2


Page141

z

QUsed is the measured quality of the used frequency.

z

TUsed2d is the absolute quality threshold of the cell that uses the current frequency. Based on the service type (CS , PS domain R99 service, or PS domain HSPA service) and measurement quantity (CPICH Ec/No or RSCP), this threshold can be configured through one of the following parameters:




Inter-freq CS measure start RSCP THD



z

H2d is the event 2D hysteresis value 2D hysteresis.

z

After the conditions of event 2D are fulfilled and maintained until the parameter 2D event trigger delay time is reached, the UE reports the event 2D measurement report message.

Note: Any of the Ec/No and RSCP measurement result can trigger the 2D event.

207

Parameters of inter-RAT handover z

Inter-RAT CS measure start Ec/No THD

z

Inter-RAT R99 PS measure start Ec/No THD

z


2D hysteresis

z


Inter-RAT H measure start RSCP THD

z


Inter-RAT R99 PS measure start RSCP THD

z


Inter-RAT CS measure start RSCP THD

z


Inter-RAT H measure start Ec/No THD

z






z

Page142

The parameters for inter-RAT handover 2D are similar with inter-frequency handover.

Set above parameters through ADD CELLINTERRATHOCOV/MOD CELLINTERRATHOCOV/SET INTERRATHOCOV z

208

Coverage-based inter-RAT handover 2F EVENT

z

Event 2F is triggered on the basis of the following formula

QUsed >= TUsed2d - H2d/2


Page143

QUsed is the measured quality of the used frequency. TUsed2f is the absolute quality threshold of the cell that uses the current frequency. Based on the service type (CS , PS domain R99 service or PS domain HSPA service) and measurement quantity (CPICH Ec/No or RSCP), this threshold can be configured through the following parameters:






Inter-freq H measure stop RSCP THD H2f is the event 2F hysteresis value 2F hysteresis.

After the conditions of event 2F are fulfilled and maintained until the parameter 2F event trigger delay time is reached, the UE reports the event 2F measurement report message.

Note: Any of the Ec/No and RSCP measurement result can trigger the 2F event.

209



z


z


Inter-RAT H measure stop Ec/No THD

z



Inter-freq CS measure stop RSCP THD The default value of this parameter is -97 dBm

z


z

Inter-RAT H measure stop RSCP THD

z


2F hysteresis

z




The default value of this parameter is D1280 (1280 ms) Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

z

Page144

The parameters for inter-RAT handover 2D are similar with inter-frequency handover.

Set above parameters through ADD CELLINTERRATHOCOV/MOD CELLINTERRATHOCOV/SET INTERRATHOCOV

z

210

Coverage-based inter-RAT handover Interoperability Between Inter-RAT and Inter-Frequency Handover Inter-frequency measurement

z

2D, 2F Event

Inter-frequency neighbor

Measure inter-frequency neighbor?

Inter-RAT measurement

z

2D, 2F Event

Inter-RAT neighbor

Measure interRAT neighbor?


Page145

During the coverage-based and QoS-based UMTS-to-GSM handover, the measurements on both inter-frequency and inter-RAT neighboring cells can be made, which enables the cells to provide continuous coverage and high quality. The preconditions for the measurements are as follows:

Both inter-frequency and inter-RAT neighboring cells are available.

Inter-freq and Inter-RAT coexist switch is set to SIMINTERFREQRAT. If Inter-freq and Inter-RAT coexist switch is set as follows:

Inter-frequency measurement, which means that the RNC allows the UE to perform only this type of measurement.

Inter-RAT measurement, which means that the RNC allows the UE to perform only this type of measurement.

Concurrent inter-frequency and inter-RAT measurement, which means that the RNC allows the UE to perform both types of measurement in compressed mode at the same time.

211


z

Inter-freq and Inter-RAT coexist switch

Parameter ID: InterFreqRATSwitch

The default value of this parameter is SIMINTERFREQRAT

InterFreq & InterRat coexist measure threshold choice

Parameter ID: CoexistMeasThdChoice

The default value of this parameter is COEXIST_MEAS_THD_CHOICE_INTERFREQ


z

Page146

Inter-freq and Inter-RAT coexist switch

Parameter ID : InterFreqRATSwitch

Value range INTERFREQ, INTERRAT, SIMINTERFREQRAT

The default value of this parameter is SIMINTERFREQRAT

Content: This parameter specifies the type of cells to be measured when inter-frequency and interRAT adjacent cells coexist:

InterFreq: means that only the inter-frequency cells are measured and inter-frequency handover is performed. InterRAT: means that only the GSM cells are measured and inter-RAT handover is performed. SimInterFreqRAT: means that both inter-frequency and inter-RAT cells are measured and interfrequency or inter-RAT handover is performed according to the type of the cell that first meets the condition for handover decision. If only the inter-frequency cells or inter-RAT cells exist, the value of this parameter is invalid

Set this parameter through ADD CELLHOCOMM/MOD CELLHOCOMM

During the concurrent inter-frequency and inter-RAT measurement, the values of the parameter InterFreq & InterRat coexist measure threshold choice for events 2D and 2F are chosen as follows:

When the value COEXIST_MEAS_THD_CHOICE_INTERFREQ is chosen, the inter-frequency measurement threshold for event 2D is used.

When the value COEXIST_MEAS_THD_CHOICE_INTERRAT is chosen, the inter-RAT measurement threshold for event 2D is used.

InterFreq & InterRat coexist measure threshold choice •Parameter ID: CoexistMeasThdChoice Value range COEXIST_MEAS_THD_CHOICE_INTERFREQ, COEXIST_MEAS_THD_CHOICE_INTERRAT

The default value of this parameter is COEXIST_MEAS_THD_CHOICE_INTERFREQ

Content: This parameter specifies the type of event 2D/2F measurement thresholds when interfrequency and inter-RAT adjacent cells coexist.

COEXIST_MEAS_THD_CHOICE_INTERFREQ: represents the event 2D/2F measurement threshold for the inter-frequency measurement.

COEXIST_MEAS_THD_CHOICE_INTERRAT: represents the event 2D/2F measurement threshold for the inter-RAT measurement.

Set this parameter through SET HOCOMM/ADD CELLHOCOMM/MOD CELLHOCOMM

212

Coverage-based inter-RAT handover Handover Measurement

RNC

UE Measurement report

2D

Physical Channel Recfg (CM) Physical Channel Recfg Complet(CM) Measurement control


Page147

When the UE enters the compress mode, RNC will trigger the inter-RAT handover measurement by one additional measurement control signaling , so as to request UE test inter-RAT neighbor cell. In this Measurement control message, RNC should inform the UE inter-RAT measurement parameter (Neighbor list, reporting mode…)

213

Coverage-based inter-RAT handover Handover Measurement •Report Mode

RNC

UE

RNC

UE

Measurement control (Event triggering, GSM RSSI ,WCDMA RSCP or Ec/No) Measurement control (Periodical, RSSI) Measurement report

Measurement report (3A)

Measurement report Measurement report

Handover

Handover

Periodical_reporting


Event_trigger

Page148

The measurement report mode of inter-RAT handover is configured through the parameter Interfrequency measure report mode. By default ,periodically reporting is recommended. Based on the measurement control message received from the RNC, the UE periodically reports the measurement quality of the target cell. Then, based on the measurement report, the RNC makes the handover decision and performs handover. If the reporting mode is periodically reporting : UE only test the inter-RAT neighbor RSSI only. If the reporting mode is event trigger reporting : UE test the inter-RAT neighbor RSSI and current cell Ec/No or RSCP ( depend on the 3A Measure Quantity ) .

214

Parameters of inter-RAT handover Inter-RAT report mode

z

Parameter ID: InterRATReportMode


Inter-RAT period report interval

z

Parameter ID: InterRATPeriodReportInterval



z

Page149

Inter-RAT report mode

Parameter ID: InterRATReportMode

Value range :Periodical reporting, Event trigger


Content: This parameter specifies the inter-frequency measurement report mode.

Set this parameter through ADD CELLINTERRATHOCOV/MOD CELLINTERRATHOCOV/SET INTERRATHOCOV

z

Inter-RAT period report interval

Parameter ID: InterRATPeriodReportInterval

Value range : NON_PERIODIC_REPORT, 250, 500, 1000, 2000, 3000, 4000, 6000, 8000, 12000, 16000, 20000, 24000, 28000, 32000, 64000

The default value of this parameter is 1000 (500ms)

Content: This parameter specifies the interval of the inter-frequency measurement report.


215

Parameters of inter-RAT handover Inter-RAT measure timer length

z

Parameter ID: InterRATMeasTime

The default value of this parameter is 60 (60 s)

3A Measure Quantity

z

Parameter ID: MeasQuantityOf3A

The default value of this parameter is Auto (based on the 2D)


z

Page150

Inter-RAT measure timer length


Value range : 0 to 512 ,step 1s

The default value of this parameter is 60 ( 60s)

Content: If no inter-RAT handover occurs upon expiry of the inter-RAT measurement timer, the system stops the inter-RAT measurement and disables the compressed mode. If this parameter is 0, the system does not start the inter-RAT measurement timer.

Set this parameter for handover based on coverage through ADD CELLINTERFREQHOCOV/MOD CELLINTERFREQHOCOV/SET INTERFREQHOCOV

z

3A Measure Quantity

Parameter ID: MeasQuantityOf3A

Value range : CPICH_Ec/No, CPICH_RSCP, Auto

The default value of this parameter is Auto (based on the 2D)

Content: This parameter indicates the measurement value of the coverage-based inter-RAT measurement in event-triggered measurement report mode.

When 3A Measure Quantity is set to Auto, the measure quantity of the used UTRAN frequency is chosen the same as the measure quantity of the reporting 2D event that triggered this inter-RAT measurement.

Set this parameter through ADD CELLINTERRATHOCOV/MOD CELLINTERFREQHOCOV/SET INTERRATHOCOV

This parameter can be configured only when Inter-RAT report mode is set to EVENT_TRIGGER. 216

Coverage-based inter-RAT handover z

Handover measurement


Event 3A is triggered on the basis of the following formula:

– QUsed <= TUsed - H3a/2 – MOtherRAT + CIOOtherRAT >= TOtherRAT + H3a/2


Page151

z

QUsed is the measurement value of the cell at the currently used frequency.

z

TUsed is the absolute quality threshold of the cell that uses the current frequency.

217


z

Inter-RAT CS Used frequency trigger Ec/No THD

Parameter ID: UsedFreqCsThdEcN0


Inter-RAT CS handover decision THD

Parameter ID: TargetRatCsThd

The default value of this parameter is 16 (-95 dBm)


z

Page152

Inter-RAT CS Used frequency trigger Ec/No THD

Parameter ID: UsedFreqCsThdEcN0



Content: If CS service inter-RAT handover uses the event-triggered measurement report

mode, event 3A is triggered only when the Ec/No value of the used frequency is lower than this threshold.

Set this parameter through ADD CELLINTERRATHOCOV/MOD CELLINTERRATHOCOV/SET

INTERRATHOCOV

z


Parameter ID: TargetRatCsThd

Value range :0 to 63, step 1dB

The default value of this parameter is 16 (-95 dBm)

Content: This parameter indicates the requirement of CS service inter-RAT handover for the quality of inter-RAT cells.

If the event-triggered measurement report mode is used, event 3A may be triggered when the quality of the target frequency is higher than this threshold. In periodical measurement report mode, this parameter is used to evaluate the coverage-based inter-RAT handover on the RNC side.

The value 0 means that the physical value is smaller than –110 dBm. .

Set this parameter through ADD CELLINTERRATHOCOV/MOD CELLINTERRATHOCOV/SET

INTERRATHOCOV

218

Parameters of inter-RAT handover 3A Event default setting

Used cell

Target cell

CS Ec/No threshold

-12dB

-95dBm

PS Ec/No threshold

-13dB

H Ec/No threshold

-13dB

CS RSCP threshold

-97dBm

PS RSCP threshold

-107dBm

H RSCP threshold

-107dBm

-95dBm


Page153

219


z

3A hysteresis


The default value of this parameter is 4(2 dB)





z

Page154

3A hysteresis


Value range 0 to 15 , step 0.5dB

The default value of this parameter is 4 (2 dB)

Content: This parameter specifies the event 3A trigger hysteresis, which is related to

slow fading. The greater the value of this parameter, the smaller the probability of ping-pong effect and misjudgment. In this case, however, the event cannot be triggered in time . Set this parameter through ADD CELLINTERRATHOCOV/MOD CELLINTERRATHOCOV/SET INTERRATHOCOV

z



Value range :D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320, D640, D1280, D2560, D5000

The default value of this parameter is 0 ( 0ms )

Content: This parameter specifies the time of event 3A trigger delay, which is related to slow fading. The greater the value of this parameter, the smaller the probability of misjudgment. In this case, however, the event responds to the changes of measured signals at a lower speed.


220


z

Cell Individual Offset

Parameter ID: CIO

The default value of this parameter is 0 dB

Neigbhoring cell oriented CIO




zCell

Page155

Individual Offset

Parameter ID: CIO

Value range –50 to 50 , step 1dB


Content: This parameter cooperates with the Neighboring cell oriented CIO

in inter-RAT handover decision. The larger the sum, the higher the handover priority of the GSM cell. The smaller the sum, the lower the handover priority of the GSM cell.

Set this parameter through ADD GSMCELL/MOD GSMCELL

zNeigbhoring

cell oriented CIO


Value range :–50 to 50 , step 1dB

The default value of this parameter is 0 (0 dB)

Content: This parameter is used in inter-RAT handover decision. The larger

the parameter, the higher the handover priority of the GSM cell. The smaller the parameter, the lower the handover priority of the GSM cell .

Set this parameter through ADD GSMNCELL/MOD GSMNCELL

221

Coverage-based Inter-RAT handover Handover Decision and Execution

Periodical Measurement Report Mode



Page156

The coverage-based handover decision is categorized into two types according to the following two measurement report modes: periodical measurement report mode and event-triggered measurement report mode. Each mode corresponds to a different decision and execution procedure.

222

Coverage-based inter-RAT handover z

Handover Decision and Execution Periodical Measurement Report Mode

The target cell must meet the requirement

– Mother_RAT + CIOother_RAT ≥ Tother_RAT + H/2

NOTE: No consideration of the current cell


Page157

z

Mother_RAT is the measurement result of inter-RAT handover received by the RNC.

z

CIOother_RAT is the cell individual offset value of the target cell. It is equal to the sum of Cell oriented Cell Individual Offset and Neigbhoring cell oriented CIO. Neigbhoring cell oriented CIO indicates the offset of the measurement cell relative to the best cell.

z

Tother_RAT is the decision threshold of inter-RAT hard handover. Based on the service type (CS or PS service) and measurement quantity (CPICH Ec/No or RSCP), this threshold can be configured through the following parameters:


Inter-RAT R99 PS handover decision THD

Inter-RAT H handover decision THD

NOTE: These thresholds are the same as the quality threshold of event 3A. z

For H is the inter-RAT handover hysteresis value Inter-RAT hysteresis.

z

Select the cells in sequence, that is, from high quality cells to low quality ones, to initiate UMTS-toGSM handover in the cells where the handover time-to-trigger timer expires.

z

The length of the time-to-trigger timer is configured through the parameter Time to trigger for verified GSM cell (with BSIC acknowledged) or the parameter Time to trigger for non-verified GSM cell (with BSIC unacknowledged).

223


z

z

Time to trigger for verified GSM cell

Parameter ID: TimeToTrigForVerify

The default value of this parameter is 0 (0 ms)

Time to trigger for non-verified GSM cell

Parameter ID: TimeToTrigForNonVerify

The default value of this parameter is 65535 (never)

Inter-RAT hysteresis

Parameter ID: HystforInterRAT



z

Page158

Time to trigger for verified GSM cell

Parameter ID : TimeToTrigForVerify

Value range 0 to 64000, step:1ms

The default value of this parameter is 0 (0 ms)

Content: This parameter specifies the delay time for triggering a GSM cell with BSIC acknowledged.

In the period specified by this parameter, if the signal quality of an adjacent GSM cell meets the requirement of inter-RAT handover, and this cell is acknowledged, the network will start inter-RAT handover.


z

Time to trigger for non-verified GSM cell

Parameter ID: TimeToTrigForNonVerify

Value range 0 to 64000 , 65535 , step:1ms

The default value of this parameter is 65535 (never)

Content: This parameter specifies the delay time for triggering a GSM cell with BSIC unacknowledged.

In the period specified by this parameter, if the signal quality of an adjacent GSM cell meets the requirement of inter-RAT handover, and this cell is unacknowledged, the network will start inter-RAT handover.

The value 65535 means that the RNC does not perform handover to an unacknowledged GSM cell. .


z

Inter-RAT hysteresis

Parameter ID: HystforInterRAT

Value range 0 to 15 , step:0.5dB


Content: This parameter determines whether to trigger inter-RAT handover decision together with the quality threshold. The smaller the shadow fading, the smaller the value of this parameter.


224

Coverage-based inter-frequency handover Handover Decision and Execution Event-Triggered Measurement Report Mode Based on the event 3A


Page159

After receiving the event 3A measurement report of GSM cells, the RNC performs the following decision and execution procedures: z

Put all the GSM cells that trigger event 3A into a cell set and arrange the cells according to the measurement quality in descending order.

z

Select the cells in sequence from the cell set to perform inter-RAT handover.

225




Page160

226

Procedure of QoS-based inter-RAT handover :

The handover procedure is divided into four phases: handover triggering, handover measurement, handover decision, and handover execution. Besides the triggering step, the rest 3 steps are the same with Coverage-based inter-RAT handover z

In the triggering phase If the service quality of the current cell deteriorates, the Link Stability Control Algorithm makes a handover measurement decision.

z

In the measurement phase The RNC requests the NodeB and the UE to start the compressed mode to measure the qualities of interfrequency and inter-RAT neighboring cells. Then, the RNC sends measurement control messages for inter-frequency measurement and inter-RAT measurement In the measurement phase, the method of periodical measurement report or event-triggered measurement report can be used.

z

In the decision phase After the UE reports event 3A, the RNC performs the handover. Otherwise, the UE periodically generates measurement reports, and the RNC makes a decision after evaluation.In the execution phase The RNC executes the handover procedure.

Note : About “Link Stability Control Algorithm” : When the uplink transmit power of the UE or downlink transmitted code power of the NodeB exceeds the associated threshold : z

For AMR, a fixed sequence of rate downsizing, inter-frequency handover, and then inter-RAT handover are performed,

z

for VP ,inter-frequency handover are performed,

z

For BE service, rate downsizing, inter-frequency handover, and then inter-RAT handover are performed according to the configured sequence 227

Parameters of inRAT-frequency handover

InterRAT Handover Switch based on Uplink Traffic AMR

z

Parameter ID: UlQoSAmrInterRATHoSwitch


InterRAT Handover Switch based on Downlink Traffic AMR

z

Parameter ID: DlQoSAmrInterRATHoSwitch



zInterRAT

Handover Switch based on Uplink/Downlink Traffic AMR

Parameter ID : UlQoSAmrInterRATHoSwitch/

Page162

DlQoSAmrInterRATHoSwitch

Value range NO, YES


Content: If the value of this parameter is YES, inter-RAT handover can be

executed on the basis of the downlink/uplink QoS of AMR services.


228

Parameters of inter-frequency handover First / Second / Third Uplink QOS Enhancement Action for Traffic BE

z

Parameter ID: BeUlAct1/ BeUlAct2/ BeUlAct3



z

Parameter ID: BeDlAct1/ BeDlAct2/ BeDlAct3



z

Page163

First / Second / Third Uplink QOS Enhancement Action for Traffic BE

Parameter ID : BeUlAct1/ BeUlAct2/ BeUlAct3



Content: This parameter defines the action sequence to enhance the Uplink QoS of

BE services .

z



Parameter ID : BeDlAct1/ BeDlAct2/ BeDlAct3



Content: This parameter defines the action sequence to enhance the downlink QoS

of BE services .


229

Parameters of inter-RAT handover Down Link QoS Measure timer length

z

Parameter ID: DLQoSMcTimerLen



z

Parameter ID: UpQoSMcTimerLen


3A Used-Freq Measure Quantity for QoS

z

Parameter ID: UsedFreqMeasQuantityForQoS3A

The default value of this parameter is CPICH_RSCP Copyright © 2008 Huawei Technologies Co., Ltd. All rights reserved.

Page164

These two parameters are shared by QoS based inter-frequency and QoS based inter-RAT handover:



Set these parameters through ADD CELLQOSHO/MOD CELLQOSHO/SET QOSHO

z

3A Used-Freq Measure Quantity for QoS

Parameter ID : UsedFreqMeasQuantityForQoS3A

Value range CPICH_Ec/No, CPICH_RSCP

The default value of this parameter is CPICH_RSCP

Content: This parameter indicates the measurement quantity used in QoS-based UMTS-to-GSM measurement in event-triggered reporting mode.

If the coverage and QoS-based UMTS-to-GSM handovers are triggered simultaneously, the RNC distributes QoS-based measurement parameters.

Set this parameter through ADD CELLQOSHO/MOD CELLQOSHO/SET QOSHO

230




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231

Procedure of Load-based inter-RAT handover :

The handover procedure is divided into three phases: handover triggering, handover decision, and handover execution z

In the triggering phase When the load of the UMTS cell that the UE accesses is higher than the related threshold, the Load Reshuffling (LDR) algorithm makes a handover decision.

z

In the measurement phase The RNC enables the compressed mode and starts the inter-RAT handover measurement.

z

In the decision phase After the UE reports event 3C, the RNC makes a handover decision.

z


Based on the service ARP, Traffic class, Channel type(R99, HSDPA), RNC will choose the users with lower priority to execute handover .

232

Parameters of inter-RAT handover Inter-RAT measure timer length

z


The default value of this parameter is 60 s


z

Page167

Inter-RAT measure timer length

Parameter ID : InterRATMeasTime

Value range 0 to 512


Content: If no inter-RAT handover occurs upon expiry of the inter-RAT

measurement timer, the system stops the inter-RAT measurement and disables the compressed mode. If this parameter is 0, the system does not start the inter-RAT measurement timer. Set this parameter through ADD CELLINTERRATHONCOV/MOD CELLINTERRATHOCOV/SET INTERRATHONCOV

233

Load-based inter-RAT handover 3C EVENT

z


MOtherRAT + CIOOtherRAT >= TOtherRAT + H3c/2


Page168

MOtherRAT is the measurement value of the cell (in another RAT) in the reporting range. CIOOtherRAT is the cell individual offset value of the cell (in another RAT) in the reporting range, which is equal to the sum of Cell oriented Cell Individual Offset and Neighboring cell oriented CIO.

TOtherRAT is the absolute inter-RAT handover threshold. Based on the service type (CS , PS domain R99 service, or PS domain HSPA service), this threshold can be configured through the following parameters:


Inter-RAT R99 PS handover decision THD H3c is 3C hysteresis, the hysteresis value of event 3C.

For the PS and CS combined services, the threshold(s) for CS services is (are) used. When the conditions for event 3C are met and the delay requirement specified by the 3C event trigger delay time parameter can be satisfied, the UE sends the measurement report of event 3C.

234

Parameters of inter-RAT handover Inter-RAT CS handover decision THD

z

Parameter ID: InterRATNCovHOCSTh

The default value of this parameter is 21 (-90dBm)

Inter-RAT PS handover decision THD

z

Parameter ID: InterRATNCovHOPSThd



z

Page169


Parameter ID : InterRATNCovHOCSTh

Value range 0 to 63 ,step:1dB


Content: This parameter is used to set measurement control on the event 3C. The event 3C is triggered when the quality of the target frequency is higher than this threshold. Note that the value 0 means the physical value is smaller than -110 dBm .

Set this parameter through ADD CELLINTERRATHONCOV/MOD CELLINTERRATHOCOV/SET INTERRATHONCOV

z

Inter-RAT PS handover decision THD

Parameter ID : InterRATNCovHOPSTh

Value range 0 to 63 ,step:1dB


Content: This parameter is used to set measurement control on the event 3C. The event 3C is triggered when the quality of the target frequency is higher than this threshold. Note that the value 0 means the physical value is smaller than -110 dBm .


235

Parameters of inter-RAT handover 3C hysteresis

z




z




z

Page170

3C hysteresis

Parameter ID : Hystfor3C

Value range 0 to 15 ,step:0.5 dB


Content: This parameter specifies the event 3C trigger hysteresis, which is related to slow fading . The larger the value of this parameter, the smaller the probability of ping-pong effect and decision mistakes. In this case, however, event 3C cannot be triggered in time .


z


Parameter ID : TrigTime3C

Value range D0, D10, D20, D40, D60, D80, D100, D120, D160, D200, D240, D320, D640,

D1280, D2560, D5000


Content: This parameter specifies the time of event 3C trigger delay, which is related to

slow fading. The larger the value of this parameter, the smaller the probability of decision mistakes. In this case, however, event 3C responds to the changes of measured signals more slowly.


236

Load-based inter-RAT handover z

Decision and Execution Procedure

Decision

3C Event

load information interchanging between the 3G and 2G cell

Execution


Page171

After receiving the event 3C measurement report of GSM cells, the RNC performs the following handover decision and execution procedure:

Put all the GSM cells that trigger event 3C into a cell set and arrange the cells according to the measurement quality in descending order.

Select the cells in sequence from the cell set.

The load status between the source cell and the target cell can be acquired by interchanging load information between a UMTS cell and a GSM cell during the load-based and service-based UMTS-to-GSM handover. Thus, whether to further conduct the handover can be determined to avoid the 2G cell overload and possible handover to the congested cell.

237

The procedure of load information interchanging between the 3G source cell and 2G target cell is described as follows:

When the RNC sends a RELOCATION REQUIRED message to the 3G CN,

If the switch Send Load Info to GSM Ind is set to ON, the RELOCATION REQUIRED message includes the load information of the 3G source cell. If the switch Send Load Info to GSM Ind is set to OFF, then the RELOCATION REQUIRED message does not include the Information

When the RNC receives the RELOCATION COMMAND message from the 2G CN,

If the switch NCOV Reloc Ind based on GSM cell load is set to ON, the RNC obtains the load information of the 2G target cell by reading the RELOCATION COMMAND message. If the 2G load is lower than CS domain Reloc GSM load THD (for CS service), or if the 2G load is lower than PS domain Reloc GSM load THD (for PS service), the RNC continues the inter-RAT handover procedure; otherwise, the RNC returns the RELOCATION CANCEL message to the CN to cancel this inter-RAT handover and makes another handover attempt to the next candidate cell generated in the cell list based on interRAT measurement. If the load information of the 2G target cell is not included in the RELOCATION COMMAND message, the load information of the 2G target cell is not considered and this inter-RAT handover is continued.

If the switch NCOV Reloc Ind based on GSM cell load is set to OFF, the RNC continues the inter-RAT handover procedure without considering the thresholds.

238

Parameters of inter-RAT handover Send Load Info to GSM Ind

z

Parameter ID: SndLdInfo2GsmInd

The default value of this parameter is ON

NCOV Reloc Ind based on GSM cell load

z

Parameter ID: NcovHoOn2GldInd



z

Page173

Send Load Info to GSM Ind

Parameter ID : SndLdInfo2GsmInd

Value range ON, OFF


Content:

When the parameter is set to ON, the RNC sends UMTS cell load information to the GSM CN during the non-coverage based system relocation in or out process. When the parameter is set to OFF, the RNC does not send UMTS cell load information to the GSM during the system relocation in or out process. Set this parameter through SET INTERRATHONCOV

z

NCOV Reloc Ind based on GSM cell load

Parameter ID : NcovHoOn2GldInd

Value range ON, OFF


Content:

When the parameter is set to ON, the RNC stops the non-coverage based system relocation out process if the GSM cell load exceeds the CS dormain Reloc GSM load THD or PS dormain Reloc GSM load THD. When the parameter is set to OFF, the RNC continues the system relocation out process without considering the thresholds. This parameter specifies the time of event 3C trigger delay, which is related to slow fading. The larger the value of this parameter, the smaller the probability of decision mistakes. In this case, however, event 3C responds to the changes of measured signals more slowly. Set this parameter through SET INTERRATHONCOV 239

Parameters of inter-RAT handover CS domain Reloc GSM load THD

z

Parameter ID: CSHOOut2GLoadThd

The default value of this parameter is 80 (80%)

PS domain Reloc GSM load THD

z

Parameter ID: PSHOOut2GLoadThd



z

Page174

CS domain Reloc GSM load THD

Parameter ID : CSHOOut2GLoadThd

Value range 0 to 100 ,step:1%


Content:


z

PS domain Reloc GSM load THD

Parameter ID : PSHOOut2GLoadThd

Value range 0 to 100 ,step:1%


Content:


240

Parameters of inter-RAT handover Inter-RAT handover max attempt times

z

Parameter ID: InterRATHOAttempts



z

Page175

Inter-RAT handover max attempt times

Parameter ID : InterRATHOAttempts

Value range 1 to 16


Content: This parameter specifies the maximum number of attempts of load-based

and service-based inter-RAT handover.

Set this parameter through ADD CELLINTERRATHONCOV/MOD

CELLINTERRATHONCOV/SET INTERRATHONCOV

241




Page176

242

Procedure of Service-based inter-RAT handover :

The handover procedure is divided into four phases: handover triggering, handover measurement handover decision, and handover execution z

In the triggering phase When a service is established (RAB Assignment ), If the Service Handover Indicator is set to HO_TO_GSM_SHOULD_BE_PERFORM, the RNC requests the handover to the GSM

z

In the measurement phase The RNC enables the compressed mode and starts the inter-RAT handover measurement.

z

In the decision phase After the UE reports event 3C, the RNC makes a handover decision.

z


z

service type is defined by parameters on cell level: Inter-RAT CS handover switch and Inter-RAT PS handover switch

z

When a single CS service is initially set up by the UE, the RNC allows the UMTS-to-GSM service-based handover if Inter-RAT CS handover switch is set to ON.

When a single PS service is initially set up by the UE, the RNC allows the UMTS-to-GSM service-based handover if Inter-RAT PS handover switch is set to ON.

For the CS and PS combined services, no service-based handover is trigged

service handover indicator assigned by the Core Network. Only the services with the indicator “HO_TO_GSM_SHOULD_BE_PERFORM” can trigger Service-based inter-RAT handover

243


Inter-RAT CS handover switch

z

Inter-RAT PS handover switch

z

Parameter ID:

CSServiceHOSwitch

PSServiceHOSwitch


z


z

Inter-RAT CS handover switch

z

Inter-RAT PS handover switch

Page178

Parameter ID :

CSServiceHOSwitch

PSServiceHOSwitch Value range ON, OFF


Content:

This parameter indicates whether the cell allows the service-based inter-RAT handover for the CS or PS services Set this parameter through ADD CELLHOCOMM/MOD CELLHOCOMM

244




Page179

245

UMTS-to-GSM Multimedia Fallback

VP service: •speech •videos

AMR service: •speech

WCDMA

VP

AMR

GSM

AMR


Page180

Compared with the traditional speech service of the GSM, the VP service of the UMTS can transmit not only speech services but also the images and videos captured by both parties For the UMTS-to-GSM handover, network-initiated multimedia fallback on the following occasions: z

The RNC decides to send an inter-RAT handover request after receiving periodical measurement reports or event 1F, 3A, or 3C.

z

The service is combined with a VP, and the "Alternative RAB Para" in the RAB ASSIGNMENT message is a valid AMR speech format.

246

Procedure of Multimedia Fallback

The procedure for the fallback service is described as follows: z

In the service set up stage, the CN sends the SRNC a RANAP RAB ASSIGNMENT REQUIREMENT message to set up the VP service. The message includes the "Alternative RAB Para" that has QoS parameters required for setting up the speech service.

z

During UMTS-to-GSM handover, the SRNC sends a RANAP MODIFY REQUEST message to change the VP service to the AMR speech service. In the 3GPP R6 protocol, the Alternative RAB Configuration is also added to the RAB MODIFY REQUEST message, which enables the RNC to request the CN to change the VP service to the AMR speech service.

z

The MSC initiates the Bearer Capability (BC) negotiation with the UE.

z

After the negotiation is modified, the RNC is informed of performing service change. The multimedia fallback ends when the service change is completed.

z

When the multimedia fallback ends, the RNC decides whether to perform the UMTS-to-GSM handover according to the current measurements reported by the UE.

At the beginning of the service setup, the RNC saves the RAB Para and "Alternative RAB Para" in the RAB ASSIGNMENT or REQUEST RELOCATION REQUEST message. This makes preparations for notifying the CN of changing the VP service to the AMR speech service. The CN initiates the RAB reconfiguration to inform the two calling parties of performing the multimedia fallback. The multimedia fallback of the calling party is consistent with that of the called party. The single VP service falls back to the single AMR speech service. The multiRAB service combined with VP falls back to the multi-RAB service combined with AMR. If the multimedia fallback succeeds, that is, the video phone in the service falls back to speech successfully, the inter-RAT handover is initiated. Otherwise, the inter-RAT handover fails.

247




Page182

248

PS UMTS-to-GSM Handover with NACC z

What is NACC?

z

Network Assisted Cell Change

What is the use of NACC

To reduce the delay of PS UMTS-to-GSM handover


Page183

Normal PS is realized by cell reselection, the time delay can not be guaranteed. But Some PS services have requirements for the delay. If the handover takes too long, TCP may start slowly or data transmission of the stream service may be interrupted due to the overflow of the UE buffer. The introduction of NACC enables the system information exchange between BSS and RAN , Thus the inter-system delay in PS domains, can be reduced. With NACC, the RNC sends the cell change order to the UE, which contains the GSM EDGE Radio Access Network (GERAN) system information, when the UMTS-toGSM handover in the PS domain is triggered.

249

Procedure of NACC

After the SRNC receives a measurement report from the UE, the UE is reselected to the GERAN cell according to the decision.

The SRNC sends a RAN INFORMATION REQUEST message to the SGSN.

The SGSN forwards the message to the corresponding BSS.

The BSS sends a GERAN SI/PSI message to the SRNC via the SGSN. RAN INFORMATION message can either be On-demand (single report) or Onmodification (multiple reports).

The SGSN forwards the report message to the SRNC through Iu interface.

If there are several report messages, the SRNC terminates reporting by the TERMINATION/END message.

To enable the NACC function, do as follows:

Run the SET CORRMALGOSWITCH command to set PS_3G2G_CELLCHG_NACC_SWITCH to ON.

Run the ADD GSMCELL/MOD GSMCELL command to set Inter-RAT cell support RIM indicator to TRUE.

250

Parameters of inter-RAT handover PS 3G to 2G Cell change order NACC Switch

z

Parameter ID: PS_3G2G_CELLCHG_NACC_SWITCH


Inter-RAT cell support RIM indicator

z

Parameter ID: SuppRIMFlag



zPS

3G to 2G Cell change order NACC Switch

Parameter ID : PS_3G2G_CELLCHG_NACC_SWITCH

Page185

Value range OFF, ON


Content: When it is checked, and inter-RAT handover of the PS domain

from UTRAN use cell change order method, inter-RAT handover support NACC(Network Assisted Cell Change) function.

Set this parameter through SET CORRMALGOSWITCH

zInter-RAT

Parameter ID: SuppRIMFlag

cell support RIM indicator

Value range FALSE, TRUE

The default value of this parameter FALSE

Content: The parameter indicates whether the inter-RAT cell supports RIM.

Set this parameter through ADD GSMCELL/MOD GSMCELL

251




Page186

252

UMTS to GSM Handover Retry z

In case of event triggered inter-RAT handover failure, if the cause of the failure is not a configuration failure and the retry timer expires, the handover attempts to the cell again until the retry number exceeds the maximum retry number


Page187

253

UMTS to GSM Handover Retry z

Parameters

3A event retry period

Parameter ID: PeriodFor3A


3A event retry max times

Parameter ID: AmntOfRpt3A

The default value of this parameter is 63 (infinity)


Parameter ID: PeriodFor3C



Parameter ID: AmntOfRpt3C



z

3A event retry period

z

3A event retry max times

Page188

Set this parameter through ADD CELLINTERRATHOCOV / MOD CELLINTERRATHOCOV / SET INTERRATHOCOV

z


z


Set this parameter through ADD CELLINTERRATHONCOV / MOD CELLINTERRATHONCOV / SET INTERRATHONCOV

254

Contents 3. Inter-RAT Handover 1. Inter-RAT Handover Overview 2. Inter-RAT Handover Procedure 3. Signaling Procedures for Inter-RAT Handover


Page189

255

Signaling Procedures for Inter-RAT Handover

The signaling procedures for PS and CS inter-RAT handover are different: •

UMTS-to-GSM Handover in CS Domain

•

UMTS to GSM Handover in PS Domain


Page190

256

UMTS-to-GSM Handover in CS Domain

257

UMTS-to-GSM Handover in CS Domain 1.

The SRNC sends the 3G MSC a RANAP message RELOCATION REQUIRED if the condition of inter-RAT outgoing handover is met.

2.

As indicated in the received message, the 3G MSC forwards this request to the 2G MSC on the MAP/E interface through a MAP message PREPARE HANDOVER.

3.

The 2G MSC forwards the request to the BSC. The message shown in the figure is for reference only and is subject to the actual condition of the GSM.

4.

The BSC responds to this request. The message shown in the figure is for reference only and is subject to the actual condition of the GSM.

5.

Once the initial procedures are completed in the 2G MSC/BSS, the 2G MSC returns a MAP/E message PREPARE HANDOVER RESPONSE.

6.

The 3G MSC sends the SRNC a RANAP message RELOCATION COMMAND.

7.

The SRNC sends the UE an RRC message HANDOVER FROM UTRAN through the existing RRC connection. This message may include information from one or several other systems.

8.

The BSC performs handover detection. The figure does not show such procedures as GSM BSS synchronization. The message shown in the figure is for reference only and is subject to the actual condition of the GSM.

9.

The UE sends the BSC a HANDOVER COMPLETE message.

10.

The BSC sends the MSC a HANDOVER COMPLETE message. The message shown in the figure is for reference only and is subject to the actual condition of the GSM.

11.

After detecting the UE in the coverage area of the GSM, the MSC sends the CN a MAP/E message SEND END SIGNAL REQUEST.

12.

The CN sends the former SRNC an IU RELEASE COMMAND message, requesting the former SRNC to release the allocated resource.

13.

After the bearer resource is released in the UMTS, the former SRNC sends the CN an IU RELEASE COMPLETE message.

14.

After the call ends, the CN sends the MSC a MAP/E message SEND END SIGNAL RESPONSE.

258

UMTS-to-GSM Handover in PS Domain

The signal quality of the WCDMA cell where the UE camps on is dissatisfactory or the load of the serving cell is heavy. When the UE is in CELL_DCH state, the UTRAN sends a CELL CHANGE ORDER message to the UE to perform a handover to GSM by cell reselection. The NodeB sends a RADIO LINK FAILURE INDICATION message, because the UE shuts down transmission towards the WCDMA cell after cell reselection to a GSM cell. After the UE accesses a GSM cell, the SGSN directly sends an IU RELEASE COMMAND message to the SRNC, if the Packet Data Protocol (PDP) context does not need to be transferred.

259


2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

The UE in CELL_DCH state or the UTRAN (when the UE is in CELL_FACH state) decides to initiate an inter-RAT handover in the PS domain to hand over the UE to a new GSM cell and stop the data transmission between the UE and the network. The UE sends a ROUTING AREA UPDATE REQUEST message to the 2G SGSN. The Update Type in the message indicates RA update, combined RA/LA update, or combined RA/LA update with IMSI attach. The BSS adds the CGI including the RAC and LAC of the cell to the received message before forwarding the message to a new 2G SGSN. The new 2G SGSN sends an SGSN CONTEXT REQUEST message to the old 3G SGSN to obtain the MM and PDP contexts. The old 3G SGSN validates the old PTMSI Signature. If the old P-TMSI Signature is valid, the old 3G SGSN starts a timer. Otherwise, the old 3G SGSN responds with an error cause. If the UE stays in connected mode before handover, the old 3G SGSN sends an SRNS CONTEXT REQUEST message. After receiving this message, the SRNS buffers the DPUs, stops sending the PDUs to the UE, and sends an SRNS CONTEXT RESPONSE message to the old 3G SGSN. The old 3G SGSN sends an SGSN CONTEXT RESPONSE message to the 2G SGSN, including the MM and PDP contexts. The security functions can be executed. The new 2G SGSN sends an SGSN CONTEXT ACKNOWLEDGE message to the old 3G SGSN. This informs the old 3G SGSN that the new 2G SGSN is ready to receive the PDUs belonging to the activated PDP contexts. The old 3G SGSN sends a DATA FORWARD COMMAND message to the SRNS. The SRNS starts a data-forwarding timer and sends the buffered PDUs to the old 3G SGSN. The old 3G SGSN tunnels the GTP PDUs to the new 2G SGSN. In the PDUs, the sequence numbers in the GTP header remain unchanged. The new 2G SGSN sends an UPDATE PDP CONTEXT REQUEST message to each related GGSN. Each GGSN sends an UPDATE PDP CONTEXT RESPONSE message after updating its PDP context fields. The new 2G SGSN sends an UPDATE GPRS LOCATION message, requesting the HLR to modify the SGSN number. The HLR sends a CANCEL LOCATION message to the old 3G SGSN. The old 3G SGSN responds with a CANCEL LOCATION ACK message. After the timer expires, the old 3G SGSN removes the MM and PDP contexts. The old 3G SGSN sends an IU RELEASE COMMAND message to the SRNS. After the data-forwarding timer expires, the SRNS responds with an IU RELEASE COMPLETE message. 260


The HLR sends an INSERT SUBSCRIBER DATA message to the new 2G SGSN. The 2G SGSN constructs an MM context and PDP contexts for the UE and returns an INSERT SUBSCRIBER DATA ACK message to the HLR.

15.

The HLR sends an UPDATE GPRS LOCATION ACK message to the new 2G SGSN.

16.

If the association has to be established, the new 2G SGSN sends a LOCATION UPDATE REQUEST message to the VLR. The VLR stores the SGSN number for creating or updating the association.

17.

If the subscriber data in the VLR is marked as not confirmed by the HLR, the new VLR informs the HLR. The HLR cancels the old VLR and inserts subscriber data in the new VLR. 1. 2.

3.

4.

5.

The new VLR sends an UPDATE LOCATION message to the HLR. The HLR cancels the data in the old VLR by sending a CANCEL LOCATION message to the old VLR. The old VLR acknowledges the message by responding with a CANCEL LOCATION ACK message. The HLR sends an INSERT SUBSCRIBER DATA message to the new VLR. The new VLR acknowledges the message by responding with an INSERT SUBSCRIBER DATA ACK message.

The HLR responds with a UPDATE LOCATION ACK message to the new VLR. The new VLR allocates a new TMSI and responds with a LOCATION UPDATE 6.

18.

ACCEPT message to the 2G SGSN. 19.

The new 2G SGSN checks the presence of the MS in the new RA. If all checks are successful, the new 2G SGSN constructs the MM and PDP contexts for the MS. A logical link is established between the new 2G SGSN and the UE. The 2G SGSN responds to the UE with a ROUTING AREA UPDATE ACCEPT message.

20.

The UE acknowledges the new P-TMSI by returning a ROUTING AREA UPDATE COMPLETE message, including all PDUs successfully sent to the UE before the routing area update procedure.

21.

The new 2G SGSN sends a TMSI REALLOCATION COMPLETE message to the new VLR if the UE confirms the VLR TMSI.

22.

The 2G SGSN and the BSS perform the BSS PACKET FLOW CONTEXT procedure.

261


262

WCDMA Load Control www.huawei.com


The WCDMA system is a self interference system. As the load of the WCDMA system increases, the interference rises. A relatively high interference may affect the coverage and Quality of Service (QoS) of established services. Therefore, capacity, coverage and QoS of the WCDMA system are mutually affected. The purpose of load control is to maximize the system capacity while ensuring coverage and QoS.

Objectives z


Know load control principles

Know load control realization methods in WCDMA system

Know load control parameters in WCDMA system


Contents 1. Load Control Overview 2. Load Control Algorithms


Contents 1. Load Control Overview 1.1 Load Control Algorithms Overview 1.2 Load Measurement 1.3 Priorities Involved in Load Control


Load Definition z

Load: the occupancy of capacity

z

Two kinds of capacity in WCDMA system

Hard capacity

Cell DL OVSF Code

NodeB Transport resource

NodeB processing capability (NodeB credit)

Soft capacity

Cell Power (UL and DL)


WCDMA network load can be defined by 4 factors: 1,Power ,include DL transmitting power of cell and increased UL interference (RTWP). 2,DL OVSF code of a cell 3,DL and UL NodeB processing capability which is defined by NodeB credit. 4,Iub transmission bandwidth of a NodeB The power resource is related to the mobility, distribution of the UE and also effected by the radio conditions. Therefore, for a fixed power resource, the numbers of service can be supported is not a fix result. We believe the UL and DL power resources are soft.

The Objectives of Load Control z

Keeping system stable

z

Maximizing system capacity while ensuring coverage and QoS

z

Realize different priorities for different service and different user


WCDMA network load can be defined by 4 factors: 1,Power ,include DL transmitting power of cell and increased UL interference (RTWP). 2,DL OVSF code of a cell 3,DL and UL NodeB processing capability which is defined by NodeB credit. 4,Iub transmission bandwidth of a NodeB The power resource is related to the mobility, distribution of the UE and also effected by the radio conditions. Therefore, for a fixed power resource, the numbers of service can be supported is not a fix result. We believe the UL and DL power resources are soft.

Load Control Algorithms z

The load control algorithms are applied to the different UE access phases as follows:

PUC: Potential User Control

CAC: Call Admission Control

IAC: Intelligent Admission Control

LDB : Intra-frequency Load Balancing

LDR: Load Reshuffling

OLC: Overload Control


The load control algorithms are applied to the different UE access phases as follows: Before UE access: Potential User Control (PUC) During UE access: Intelligent Access Control (IAC) and Call Admission Control (CAC) After UE access: intra-frequency Load Balancing (LDB), Load Reshuffling (LDR), and Overload Control (OLC)

Load Control Algorithms Load control algorithm in the WCDMA system


The load control algorithms are built into the RNC. The input of load control comes from the RNC and measurement information of the NodeB. RNC can calculate hard resource load, that is OVSF ,NodeB credit, Iub occupancy. The soft load need the NodeB reporting.



Soft Load Measurement The major measurement objects of the load measurement Uplink Received Total Wideband Power (RTWP) •

UL Load

Received scheduled Enhanced Dedicated Channel (E-DCH) power share (RSEPS) E-DCH Provided Bit Rate TCP Non-HSPA TCP

DL Load HSDPA PBR HSDPA GBP Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.

The soft load control algorithms use load measurement values in the uplink and the downlink. A common Load Measurement (LDM) algorithm is required to control load measurement in the uplink and the downlink. The NodeB and the RNC perform measurements and filtering in accordance with the parameter settings. The statistics obtained after the measurements and filtering serve as the data input for the load control algorithms. The major measurement objects of the LDM are as follows: Uplink Received Total Wideband Power (RTWP) •Received scheduled Enhanced Dedicated Channel (E-DCH) power share (RSEPS) •E-DCH Provided Bit Rate

Downlink Transmitted Carrier Power (TCP)

TCP of all codes not used for High Speed Physical Downlink Shared Channel (HSPDSCH), High Speed Shared Control Channel ， (Non-HSPA TCP)

Provided Bit Rate on HS-DSCH (PBR)

HS-DSCH required power ，also called Guaranteed Bit Rate (GBR) required power (GBP)

Load Measurement procedure

z

Smooth Window Filtering on the RNC Side N −1

P ( n) =

∑P

n −i

i =0

N

N : the size of the smooth window

Pn : the reported measurement value


Based on the measurement parameters set on the NodeB Local Maintenance Terminal (LMT), the NodeB measures the major measurement quantities and then obtains original measurement values. After layer 3 filtering on the NodeB side, the NodeB reports the cell measurement values to the RNC. Based on the measurement parameters set on the RNC LMT, the RNC performs smooth filtering on the measurement values reported from the NodeB and then obtains the measurement values, which further serve as data input for the load control algorithms. Filtering on the NodeB Side

A is the sampling value of the measurement. B is the measurement value after layer 1 filtering. C is the measurement value after layer 3 filtering ,which is the reported measurement value Layer 1 filtering is not standardized by protocols and it depends on vendor equipment. Layer 3 filtering is standardized. The filtering effect is controlled by a higher layer.

The interval at which the NodeB reports each measurement quantity to the RNC is configured by the Time unit and Report cycle on RNC LMT: SET LDM The report interval = Time unit * Report cycle By default, Time unit for all measurement are set to 10ms ;Report cycle for RTWP is 100, that is 1s; Report cycle for TCP and Non HSPA TCP is 20 ,that is 200ms ;Report cycle for HSDPA GBP is 10, that is 100 ms; Report cycle for HSDPA PBR is 10, that is 100 ms Smooth Window Filtering on the RNC Side After the RNC receives the measurement report, it filters the measurement value with the smooth window. Assuming that the reported measurement value is Qn and that the size of the smooth window is N, the filtered measurement value is :

Delay susceptibilities of PUC, CAC, LDB，LDR, and OLC to common measurement are different. The LDM algorithm must apply different smooth filter coefficients and measurement periods to those algorithms , on RNC LMT, we can set the smooth window length for different algorithms by SET LDM: The following table lists the parameters :

Parameter Name

Parameter ID

Value Range

default Value

PUC moving average filter length

PucAvgFilterLen

1 to 32

32

LDB moving average filter length

LdbAvgFilterLen

1 to 32

32

UL LDR moving average filter length

UlLdrAvgFilterLen

1 to 32

25

DL LDR moving average filter length

DlLdrAvgFilterLen

1 to 32

25

UL CAC moving average filter length

UlCACAvgFilterLen

1 to 32

3

DL CAC moving average filter length

DlCACAvgFilterLen

1 to 32

3

UL OLC moving average filter length

UlOLCAvgFilterLen

1 to 32

25

DL OLC moving average filter length

DlOLCAvgFilterLen

1 to 32

25

Smooth window for GBP for all related algorithms are the same and the default setting is 1



Priority z

The service of user with low priority will be affected by the load control algorithms first

z

Three kinds of priorities

User Priority

RAB Integrate Priority

User Integrate Priority


User Priority: mainly applying to provide different QoS for different users. Eg., setting different GBR according to the user priority for BE service. No consideration about the service. RAB Integrate Priority: Priority of a service, related to the service type, and the user priority of the user. User Integrate Priority: Only used for multi-RAB user ,it is a temporary priority of an ongoing-service user.

User Priority z

There are three levels of user priority

gold (high), silver (middle) and copper (low) user

User priority

Gold

Silver

Copper

Uplink

128kbps 64kbps 32kbps

Downlink

128kbps 64kbps 32kbps

gold user

Pay $100 for 3G services


In CN HLR, we can set ARP (Allocation Retention Priority ), during service setup, CN sends ARP to RNC .Based on the mapping relation( configured in RNC), RNC can identify the user is a gold, silver or copper one. The user priority affect GBR of BE service in RAN, Iub transmission management and so on.

User Priority z

The mapping relation between user priority and ARP (Allocation/Retention Priority) is configured in RNC by SET USERPRIORITY

The default relation is:

ARP

User Priority

1

2

3

Gold

4

5

6

7

8

9

Silver

10 11

12 13

14

Copper


The user priority mapping can be configured in RNC by SET USERPRIORITY ARP 15 is always the lowest priority and it cannot be configured. It corresponds to copper. If ARP is not received in messages from the Iu interface, the user priority is regarded as copper.

15

RAB Integrate Priority z

RAB Integrate Priority is mainly used in load control algorithms

z

RAB Integrate Priority are set according to :

ARP

Traffic Class

THP（for interactive service only）

HSPA or DCH


RAB Integrate Priority is mainly used in load control algorithms. The values of RAB Integrate Priority are set according to the Integrate Priority Configured Reference parameter as follows: If Integrate Priority Configured Reference is set to Traffic Class, the integrate priority abides by the following rules: Traffic classes: conversational -> streaming -> interactive -> background => Services of the same class: Priority based on Allocation/Retention Priority (ARP) values, that is, ARP1 -> ARP2 -> ARP3 -> ... -> ARP14 => Only for the interactive service of the same ARP value: priority based on Traffic Handling Priority (THP, defined in CN , sent to RNC during service setup), that is, THP1 -> THP2 -> THP3 -> ... -> THP14 => Services of the same ARP, class and THP (only for interactive services): High Speed Packet Access (HSPA) or Dedicated Channel (DCH) service preferred depending on the value of the Indicator of Carrier Type Priority parameter.

If Integrate Priority Configured Reference is set to ARP, the integrate priority abides by the following rules: ARP1 -> ARP2 -> ARP3 -> ... -> ARP14 => Traffic classes: conversational -> streaming -> interactive -> background => Only for the interactive service of the same ARP value: priority based on Traffic Handling Priority (THP), that is, THP1 -> THP2 -> THP3 -> ... -> THP14 => Services of the same ARP, class and THP (only for interactive services): HSPA or DCH service preferred depending on the value of the Indicator of Carrier Type Priority parameter. Integrate Priority Configured Reference and Indicator of Carrier Type Priority are set by SET USERPRIORITY . By default Integrate Priority Configured Reference is set to ARP Indicator of Carrier Type Priority is set to NONE, that means HSDPA and DCH services have the same priority. ARP and THP are carried in the RAB ASSIGNMENT REQUEST message, and they are not configurable on the RNC LMT.

Example for RAB Integrate Priority Based on ARP, HSDPA priority is higher Service ARP Traffic Class ID Services attribution in the cell Service ARP ID

Traffic Class

Bear type

B

1

Interactive

HSDPA

Bear type

A

1

Interactive

DCH

C

2

Conversational

DCH

D

2

Background

DCH

A

1

Interactive

DCH

B

1

Interactive

HSDPA

C

2

Conversational

DCH

D

2

Background

DCH

Based on Traffic Class, HSDPA priority is higher Service ID

Traffic Class

ARP

Bear type

C

Conversational

2

DCH

B

Interactive

1

HSDPA

A

Interactive

1

DCH

D

Background

2

DCH


This example shows the RAB Integrate Priority calculation in 2 different conditions

User Integrate Priority z

When the user has one RAB, User integrate priority is the same as the RAB integrate priority

z

For multiple RAB users, the integrate priority of the user is based on the service of the highest priority


When the user has one RAB, User integrate priority is the same as the service of the RAB integrate priority; For multiple RAB users, the integrate priority of the user is based on the service of the highest priority. User integrate priority is used in user-specific load control. For example, the selection of R99 users during preemption, the selection of users during inter-frequency load handover for LDR, and the selection of users during switching BE services to CCH are performed according to the user integrate priority.

Key parameters of Priority z

z

Integrate Priority Configured Reference

Parameter ID: PRIORITYREFERENCE

The default value of this parameter is ARP

Indicator of Carrier Type Priority

Parameter ID: CARRIERTYPEPRIORIND

The default value of this parameter is NONE


Integrate Priority Configured Reference Parameter ID: PRIORITYREFERENCE Value range: ARP, Traffic Class Content: This parameter is used to set the criterion by which the priority is first sorted. The default value of this parameter is ARP Set this parameter through SET USERPRIORITY Indicator of Carrier Type Priority Parameter ID: CARRIERTYPEPRIORIND Value range: NONE, DCH, HSPA Content: This parameter is used to decide which carrier (DCH or HSPA) takes precedence when ARP and Traffic Class are identical. When this parameter is set to NONE, the bearing priority of services on the DCH is the same as that of HSPA services. The default value of this parameter is NONE, Set this parameter through SET USERPRIORITY

Contents 2. Load Control Algorithms 2.1 PUC (Potential User Control) 2.2 LDB (Intra-Frequency Load Balancing) 2.3 CAC (Call Admission Control) 2.4 IAC (Intelligent Admission Control) 2.5 LDR (Load Reshuffling) 2.6 OLC (Overload Control)


PUC Principles z

The Potential User Control (PUC) algorithm controls the Inter-frequency cell reselection of the potential UE, and prevents UE from camping on a heavily loaded cell.

z

Potential UE :

IDLE Mode UE

CELL-FACH UE，CELL-PCH UE，URA-PCH UE


The function of PUC is to balance traffic load among inter-frequency cells. By modifying cell selection and reselection parameters and broadcasting them through system information, PUC leads UEs to cell with light load. The UE may be in idle mode, Cell_FACH state, Cell _PCH state, URA_PCH state

PUC Load Judgment


Cell load for PUC is of three states: heavy, normal, and light The RNC periodically monitors the downlink load of the cell and compares the measurement results with the configured thresholds Load level division threshold 1 and Load level division threshold 2, that is, load level division upper and lower thresholds. If the cell load is higher than the load level division upper threshold plus the Load level division hysteresis, the cell load is considered heavy. If the cell load is lower than the load level division lower threshold minus the Load level division hysteresis, the cell load is considered light. Otherwise the cell load is considered normal

PUC Procedure Threshold Every 200ms

Cell TCP

Heavy? Light? Normal?

RNC

cell reselection parameters

System information

NodeB

UE

Every 30 minutes


The parameters related to cell selection and cell reselection are Qoffset1(s,n) (load level offset), Qoffset2(s,n) (load level offset), and Sintersearch (start threshold for interfrequency cell reselection). The NodeB periodically reports the total TCP of the cell, and the PUC periodically triggers the following activities: Assessing the cell load level based on the total TCP Configuring Sintersearch, Qoffset1(s,n), and Qoffset2(s,n) based on the cell load level PUC can Modify inter-frequency cell reselection parameters based on the load: 1. Sintersearch : when the load of a cell is “Heavy”, PUC will increase Sintersearch when the load of a cell is “Light”, PUC will decrease Sintersearch 2. QOffset: when the load of current cell is “Heavy” and neighbor is “Non heavy”, PUC will decrease QOffset when the load of current cell is “Non heavy” and neighbor is “Heavy”, PUC will increase QOffset Updating the parameters of system information SIB3 and SIB11

Load of Current Cell

Sintersearch

Light

S'intersearch = Sintersearch + Sintersearch offset 1

↘

Normal

S'intersearch = Sintersearch

→

Heavy

S'intersearch = Sintersearch + Sintersearch offset 2

↗

→: indicates that the parameter value remains unchanged. ↗: indicates that the parameter value increases. ↘: indicates that the parameter value decreases.

Change of Sintersearch

PUC Principles Light load Freq1

Modify System Info SIB3,11

1.Hard to trigger reselection 2.Easy to camp on the cell Increase the POTENTIAL load

Normal load Stay System Info SIB3,11

Heavy load

Freq2 1.Easy to trigger reselection

2.Easy to select light load Inter-freq neighbor Cell

Modify

Decrease the POTENTIAL load

System Info SIB3,11

Idle state

CCH state


Based on the characteristics of inter-frequency cell selection and reselection. Sintersearch When this value is increased by the serving cell, the UE starts inter-frequency cell reselection ahead of schedule. When this value is decreased by the serving cell, the UE delays inter-frequency cell reselection. Qoffset1(s,n): applies to R (reselection) rule with CPICH RSCP When this value is increased by the serving cell, the UE has a lower probability of selecting a neighboring cell. When this value is decreased by the serving cell, the UE has a higher probability of selecting a neighboring cell. Qoffset2(s,n): applies to R (reselection) rule with CPICH Ec/I0 When this value is increased by the serving cell, the UE has a lower probability of selecting a neighboring cell. When this value is decreased by the serving cell, the UE has a higher probability of selecting a neighboring cell.

Key parameters PUC z

z

z

Cell LDC algorithm switch

Parameter ID: NBMLDCALGOSWITCH PUC

The default value of this parameter is Off

Load level division threshold 1 (Heavy)

Parameter ID: SPUCHEAVY

The default value of this parameter is 70(70%)

Load level division threshold 2 (Light)

Parameter ID: SPUCLIGHT



Cell LDC algorithm switch Parameter ID: NBMLDCALGOSWITCH PUC Value range: OFF, ON Content: This parameter is used to enable or disable the PUC algorithm.. The default value of this parameter is OFF Set this parameter through ADD CELLALGOSWITCH / MOD CELLALGOSWITCH

Load level division threshold 1 (Heavy) Parameter ID: SPUCHEAVY Value range: 0 to 100 Content: This parameter is one of the thresholds used to assess cell load level and to decide whether the cell load level is heavy or not. The default value of this parameter is 70%, Set this parameter through ADD CELLPUC / MOD CELLPUC Load level division threshold 2 (Light) Parameter ID: SPUCLIGHT Value range: 0 to 100 Content: This parameter is one of the thresholds used to assess cell load level and to decide whether the cell load level is heavy or not. The default value of this parameter is 45%, Set this parameter through ADD CELLPUC / MOD CELLPUC


z

Load level division hysteresis

Parameter ID: SPUCHYST


PUC period timer length

Parameter ID: PUCPERIODTIMERLEN

The default value of this parameter is 1800(s)


Load level division hysteresis Parameter ID: SPUCHYST Value range: OFF, ON Content: This parameter specifies the hysteresis used during cell load level assessment to avoid unnecessary ping-pong effect of a cell between two load levels due to a little load change. The default value of this parameter is 5 (5%) Set this parameter through ADD CELLPUC / MOD CELLPUC PUC period timer length Parameter ID: PUCPERIODTIMERLEN Value range: 6 to 86400 s Content: This parameter specifies the period of potential user control. The higher the parameter is set, the longer the period to trigger the PUC is. The default value of this parameter is 1800(s) Set this parameter through SET LDCPERIOD


z

Sintersearch offset 1

Parameter ID: OFFSINTERLIGHT

The default value of this parameter is –2 (-4dB)

Sintersearch offset 2

Parameter ID: OFFSINTERHEAVY



Sintersearch offset 1 Parameter ID: OFFSINTERLIGHT Value range: –10 to 10 ,step:2dB Content: This parameter defines the offset of Sintersearch when the center cell load level is "Light". It is strongly recommended that this parameter be set to a value not higher than 0. The default value of this parameter is –2 (-4dB) Set this parameter through ADD CELLPUC / MOD CELLPUC Sintersearch offset 2 Parameter ID: OFFSINTERHEAVY Value range: –10 to 10 ,step:2dB Content: This parameter defines the offset of Sintersearch when the center cell load level is "Heavy". It is strongly recommended that this parameter be set to a value not lower than 0. The default value of this parameter is 2 (4dB) Set this parameter through ADD CELLPUC / MOD CELLPUC


z

Qoffset1 offset 1

Parameter ID: OFFQOFFSET1LIGHT


Qoffset1 offset 2

Parameter ID: OFFQOFFSET1HEAVY



Qoffset1 offset 1 Parameter ID: OFFQOFFSET1LIGHT Value range: –10 to 10 ,step:2dB Content: This parameter defines the offset of Qoffset1（RSCP） when the current cell has heavy load and the neighboring cell has light or normal load. To enable the UE to select a neighboring cell with relatively light load, it is strongly recommended that this parameter be set to a value not higher than 0. The default value of this parameter is -4 (-8dB) Set this parameter through ADD CELLPUC/MOD CELLPUC Qoffset1 offset 2 Parameter ID: OFFQOFFSET1HEAVY Value range: –10 to 10 ,step:2dB Content: This parameter defines the offset of Qoffset1（RSCP） when the load of a neighboring cell is heavier than that of the center cell. To enable the UE to select a neighboring cell with relatively light load, it is strongly recommended that this parameter be set to a value not lower than 0. The default value of this parameter is 4 (8dB) Set this parameter through ADD CELLPUC/MOD CELLPUC


z

Qoffset2 offset 1

Parameter ID: OFFQOFFSET2LIGHT


Qoffset2 offset 2

Parameter ID: OFFQOFFSET2HEAVY



Qoffset1 offset 1 Parameter ID: OFFQOFFSET1LIGHT Value range: –10 to 10 ,step:2dB Content: This parameter defines the offset of Qoffset1（RSCP） when the current cell has heavy load and the neighboring cell has light or normal load. To enable the UE to select a neighboring cell with relatively light load, it is strongly recommended that this parameter be set to a value not higher than 0. The default value of this parameter is -4 (-8dB) Set this parameter through ADD CELLPUC/MOD CELLPUC Qoffset1 offset 2 Parameter ID: OFFQOFFSET2HEAVY Value range: –10 to 10 ,step:2dB Content: This parameter defines the offset of Qoffset2（EcNo） when the load of a neighboring cell is heavier than that of the center cell. To enable the UE to select a neighboring cell with relatively light load, it is strongly recommended that this parameter be set to a value not lower than 0. The default value of this parameter is 4 (8dB) Set this parameter through ADD CELLPUC / MOD CELLPUC



Intra-Frequency Load Balancing z

Intra-frequency Load Balancing (LDB) is performed to adjust the coverage areas of cells by modifying PCPICH power

z

LDB affect UEs in all states


Intra-frequency Load Balancing (LDB) is performed to adjust the coverage areas of cells according to the measured values of cell downlink power load. RNC checks the load of cells periodically and adjusts the transmit power of the P-CPICH in the associated cells based on the cell load. When the load of a cell increases, the cell reduces its coverage to lighten its load. When the load of a cell decreases, the cell extends its coverage so that some traffic is off-loaded from its neighboring cells to it. Reduction of the pilot power will make the UEs at the edge of the cell handed over to neighboring cells, especially to those with a relatively light load and with relatively high pilot power. After that, the downlink load of the cell is lightened accordingly.

LDB Procedure Threshold

Cell TCP

Heavy?

Handover or

Light?

Cell Reselection

Normal?

RNC

Modify cell PCPICH power

Updated PCPICH POWER

NodeB

UE


The NodeB periodically reports the total TCP of the cell, and the LDB periodically triggers the following activities: Assessing the cell load level based on the total TCP If the downlink load of a cell is higher than the value of the Cell overload threshold, it is an indication that the cell is heavily loaded. In this case, the transmit power of the PCPICH needs to be reduced by a step, which is defined by the Pilot power adjustment step parameter. However, if the current transmit power is equal to the value of the Min transmit power of PCPICH parameter, no adjustment is performed. If the downlink load of a cell is lower than the value of the Cell underload threshold, it is an indication that the cell has sufficient remaining capacity for more load. In this case, the transmit power of the P-CPICH increases by a step, which is defined by the Pilot power adjustment step parameter, to help to lighten the load of neighboring cells. However, if the current transmit power is equal to the value of the Max transmit power of PCPICH parameter, no adjustment is performed.

Key parameters LDB z

z


Parameter ID: NBMLdcAlgoSwitch LDB

The default value of this parameter is Off

Intra-frequency LDB period timer length

Parameter ID: IntraFreqLdbPeriodTimerLen

The default value of this parameter is 1800 (s)


Cell LDC algorithm switch Parameter ID: NBMLdcAlgoSwitch LDB Value range: OFF, ON Content: This parameter is used to enable or disable the LDB algorithm.. The default value of this parameter is OFF Set this parameter through ADD CELLALGOSWITCH / MOD CELLALGOSWITCH Intra-frequency LDB period timer length Parameter ID: IntraFreqLdbPeriodTimerLen Value range: 0 to 86400 Content: This parameter specifies the length of the intra-frequency LDB period. The default value of this parameter is 1800 (s) Set this parameter through SET LDCPERIOD


z

Cell overload threshold (Heavy)

Parameter ID: CellOverrunThd


Cell underload threshold (Light)

Parameter ID: CellUnderrunThd



Cell overload threshold Parameter ID: CellOverrunThd Value range: 0 to 100 Content: If the downlink load of a cell exceeds this threshold, the algorithm can decrease the pilot transmit power of the cell so as to extend the capacity of the whole system. The default value of this parameter is 90%, Set this parameter through ADD CELLLDB / MOD CELLLDB Cell underload threshold Parameter ID: CellUnderrunThd Value range: 0 to 100 Content: If the downlink load of a cell is lower than this threshold, the algorithm can increase the pilot transmit power of the cell so as to share the load of other cells. The default value of this parameter is 30%, Set this parameter through ADD CELLLDB / MOD CELLLDB


z

Pilot power adjustment step

Parameter ID: PCPICHPowerPace

The default value of this parameter is 2 (0.2dB)

Max transmit power of PCPICH

Parameter ID: MaxPCPICHPower

The default value of this parameter is 346 (34.6dBm)


Pilot power adjustment step Parameter ID: PCPICHPowerPace Value range: 0 to 10 , Step 0.1dB Content: This parameter defines the step for the adjustment to the pilot power. The default value of this parameter is 2, 0.2dB Set this parameter through ADD CELLLDB / MOD CELLLDB Max transmit power of PCPICH Parameter ID: MaxPCPICHPower Value range: –100 to 500 ,Step 0.1dB Content: This parameter defines the maximum transmit power of the P-CPICH in a cell. This parameter has to be set according to the actual system environment, that is, for example, cell coverage (radius) and geographical environment. If the maximum transmit power of the P-CPICH is set too low, the cell coverage decreases. When a certain proportion of soft handover area is ensured, any more increase in the pilot power achieves no improvement on the performance of the downlink coverage. The default value of this parameter is 346 (34.6dBm) Set this parameter through ADD PCPICH / MOD PCPICHPWR

Key parameters LDB Min transmit power of PCPICH

Parameter ID: MinPCPICHPower

The default value of this parameter is 313 (31.3dBm)


Min transmit power of PCPICH Parameter ID: MinPCPICHPower Value range: -100 to 500 Content: This parameter defines the minimum transmit power of the P-CPICH in a cell. This parameter has to be set according to the actual system environment, that is, for example, (radius) and geographical environment. If the minimum transmit power of the P-CPICH is set too low, the cell coverage will be affected. The parameter has to be set under the condition that a certain proportion of soft handover area is ensured or the occurrence of coverage hole can be prevented. The default value of this parameter is 313 (31.3dBm) Set this parameter through ADD PCPICH / MOD PCPICHPWR



Why we need CAC? z

WCDMA is an interference limited system, after a new call is admitted, the system load will be increased

z

If a cell is high loaded, a new call will cause ongoing user dropped

z

We must keep the coverage planned by the Radio Network Planning


CAC is needed under such scenarios: 1. RRC connection setup request 2. RAB setup and Bandwidth increasing 3. Handover 4. RB reconfiguration

Flow chart of CAC


The admission decision is based on: •

Cell available code resource: managed in RNC

•

Cell available power resource, that is DL/UL load : measured in NodeB

•

NodeB resource state, that is, NodeB credits : managed in RNC

•

Available Iub transport layer resource, that is, Iub transmission bandwidth: managed in RNC

•

HSPA user number (only for HSPA service)

Algorithm Switch of CAC Admission control Switches can be set on RNC LMT: z

z

z

Power CAC

Uplink CAC algorithm switch

Downlink CAC algorithm switch

NodeB Credit CAC

CAC algorithm switch : CacSwitch

Cell CAC algorithm switch: CRD_ADCTRL

HSDPA user number CAC

z

CAC algorithm switch :HSDPA_UU_ADCTRL

HSUPA user number CAC

CAC algorithm switch: HSUPA_UU_ADCTRL


Except the mandatory code and Iub resource admission control, the admission control based on power and NodeB credit ,HSDPA User Number can be disabled through the LMT command: Power CAC can be switched off by ADD CELLALGOSWITCH / MOD CELLALGOSWITCH Uplink CAC algorithm switch (NBMULCACALGOSELSWITCH ) specifies the algorithm used for power admission in the uplink. Downlink CAC algorithm switch (NBMDLCACALGOSELSWITCH) specifies the algorithm used for power admission in the downlink. NodeB Credit CAC can be switched off by SET CACALGOSWITCH or ADD CELLALGOSWITCH / MOD CELLALGOSWITCH CAC algorithm switch (CacSwitch) specifies the NodeB level credit CAC algorithm Cell CAC algorithm switch (CRD_ADCTRL) specifies the Cell level credit CAC algorithm HSDPA user number CAC switched off by ADD CELLALGOSWITCH / MOD CELLALGOSWITCH HSDPA_UU_ADCTRL specifies whether to enable or disable the HSDPA admission control algorithm. HSUPA user number CAC switched off by ADD CELLALGOSWITCH / MOD CELLALGOSWITCH HSUPA_UU_ADCTRL specifies whether to enable or disable the HSUPA admission control algorithm

CAC Based on Code Resource z

Code Resource CAC functions in:

RRC connection setup

Handover

R99 services RAB setup

Note: RRC connection setup and Handover have higher priority


When a new service attempts to access the network, code resource admission is mandatory. 1. For RRC connection setup requests, the code resource admission is successful if the current remaining code resource is enough for the RRC connection. 2. For handover services, the code resource admission is successful if the current remaining code resource is enough for the service. 3. For other R99 services, the RNC has to ensure that the remaining code does not exceed the configurable threshold after admission of the new service. 4. For HSDPA services, the reserved codes are shared by all HSDPA services. Therefore, the code resource admission is not needed. So the RRC connection setup and Handover has higher priority to access a cell

CAC Based on Power Resource z

UL and DL Power Resource CAC functions in:

R99 cell


R99 RAB setup

Handover

HSPA cell

RRC connection

R99 RAB setup

HSPA RAB setup

Handover

Note: RRC connection setup and Handover have higher priority Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.

The UL CAC and DL CAC are independent . The basic principle of Power CAC is: RNC predict the cell power load after the access. If the load will be higher than a threshold, the admission is failed. So, by setting different threshold for different access, we can realize different priorities.

Power CAC Algorithms z

Algorithm 1: based on UL/DL load measurement and load prediction (RTWP and TCP)

z

Algorithm 2: based on Equivalent Number of User (ENU)

z

Algorithm 3: loose call admission control algorithm


Huawei provide 3 Power CAC Algorithms Algorithm 1: power resource admission decision based on power or interference. Depending on the current cell load (uplink load factor and downlink transmitted carrier power) and the access request, the RNC determines whether the cell load will exceed the threshold upon admitting a new call. If yes, the RNC rejects the request. If not, the RNC accepts the request. Algorithm 2: power resource admission decision based on the number of equivalent users.Based on Huawei testing and experience, The 12.2 kbit/s AMR traffic is used to calculate the Equivalent Number of Users (ENU) of all other services in UL and DL. The 12.2 kbit/s AMR traffic's ENU is assumed to be 1. Depending on the current number of equivalent users and the access request in UL and DL, the RNC determines whether the number of equivalent users will exceed the threshold upon admitting a new call. If yes, the RNC rejects the request. If not, the RNC accepts the request. Algorithm 3: power resource admission decision based on power or interference, but with the estimated load increment always set to 0.Depending on the current cell load (uplink load factor and downlink TCP) and the access request, the RNC determines whether the cell load will exceed the threshold, with the estimated load increment set to 0. If yes, the RNC rejects the request. If not, the RNC accepts the request.

Basic principle of Uplink CAC Algorithm 1 Admission request

ηUL = 1 −

Get current RTWP, and calculate the current load factor

Δη

Get the traffic characteristic, and estimate the increment of load factor

ηUL _ predicted = ηUL + Δη + ηCCH

Calculate the predicted load factor

Y

Smaller than the threshold?

admitted

PN RTWP

N

rejected

End of UL CAC Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.

Pn is uplink receive background noise. The procedure for uplink power resource decision is as follows: 1. The RNC obtains the uplink RTWP of the cell, and calculate the current uplink load factor. 2. The RNC calculates the uplink load increment ΔηUL based on the service request. 3. The RNC uses the formula ηUL,predicted=ηUL + ΔηUL to forecast the uplink load factor. 4. By comparing the forecasted uplink load factor ηUL,predicted with the corresponding threshold ,the RNC decides whether to accept the access request or not.

Basic principle of Downlink CAC Algorithm1


The procedure for downlink power resource decision is as follows: 1. The RNC obtains the cell downlink TCP, and calculates the downlink load factor by multiplying the maximum downlink transmit power by this TCP. 2. The RNC calculates the downlink load increment ΔP based on the service request and the current load. 3. The RNC forecasts the downlink load factor. 4. By comparing the downlink load factor with the corresponding threshold (DL threshold of Conv AMR service, DL threshold of Conv non_AMR service, DL threshold of other services, DL Handover access threshold), the RNC decides whether to accept the access request or not.

Basic principle of CAC Algorithm 2 Admission request

ENU

Get current total ENU Get the traffic characteristic, and estimate the increment of ENU

Smaller than the threshold?

admitted

N

∑ ENU i =1

i

ENU new

ENU total ( N + 1) = ENU total ( N ) + ENU new

Calculate the predicted ENU

Y

total

(N ) =

N

ENULoad = ENU total ( N + 1) / ENU max

rejected

End of UL/DL CAC Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.

The procedure for ENU resource decision is as follows: 1. The RNC obtains the total ENU of all exist users ENUtotal. 2. The RNC get the ENU of the new incoming user ENUnew. 3. The RNC forecast the ENU load. 4. By comparing the forecasted ENU load with the corresponding threshold (the same threshold as power resource), the RNC decides whether to accept the access request or not. The ENUmax can be set by LMT, the ENUnew and ENUi is determined by Huawei algorithm, there is an example in next slide.

Power CAC for RRC connection Setup z

For the RRC connection request is, tolerance principles are applied :

Emergency call, Detach , Registration

Direct Admission

RRC connection request for other reasons

UL/ DL OLC Trigger threshold Admission


To ensure that the RRC connection request is not denied by mistake, tolerance principles are applied. The admission decision is made for the following reasons of the RRC connection request: 1. For the RRC connection request for the reasons of emergency call, detach or registration, direct admission is used ,that is no limitation. 2. For the RRC connection request for other reasons, UL/DL OLC Trigger threshold is used for admission. By default, the OLC trigger threshold is relatively high (DL/UL 95%), which make the RRC connections are easily set up.

UL Power CAC for R99 Cell (Algorithm1) z

For R99 DCH RAB Setup, The RNC uses the following formula to predict the uplink load factor :

ηUL _ predicted = ηUL + ΔηUL + ηUL − CCH

Where the

PN RTWP By comparing the predicted uplink load factor ηUL,predicted with the

ηUL = 1 −

z

corresponding threshold ,the RNC decides whether to accept the access request or not


The threshold for Conv AMR service , Conv non_AMR service , Other R99 services , Handover are set independently, which provide different priorities. Normally, Other R99 services < Conv non_AMR service services < Conv AMR service < Handover The uplink load increment ΔηUL is determined by : 1. The Eb/No of the new incoming call 2. The uplink load increment is proportional to the value of Eb/No. 3. UL neighbor interference factor 4. Active Factor of the new incoming call

DL Power CAC for R99 Cell (Algorithm1) z

For R99 DCH RAB Setup, The RNC uses the following formula to predict the downlink load factor :

η DL _ predicted = η DL + Δη DL + η DL − CCH

Where the η DL =

z

TCP Pmax

Δη DL =

Δη DL Pmax

By comparing the predicted downlink load factor ηDL,predicted with the corresponding threshold ,the RNC decides whether to accept the access request or not


The threshold for Conv AMR service , Conv non_AMR service , Other R99 services , Handover are set independently, which provide different priorities. Normally, Other R99 services < Conv non_AMR service services < Conv AMR service < Handover The downlink load increment ΔηDL is determined by : 1. The Eb/No of the new incoming call 2. Non-orthogonality factor 3. Current transmission carrier power 4. Active Factor of the new incoming call

UL Power CAC for HSPA Cell (Algorithm1) z

The power increment of an HSUPA service is related to Ec/No, GBR requirement, neighboring interference factor, active factor of the service. The formula of UL power CAC for HSUPA is similar to that for R99

z

After RSEPS measurement is introduced, the UL RTWP is divided into two parts:

Controllable part

The UL interference generated by E-DCH scheduling services belong to the controllable part

Uncontrollable part


RSEPS: Received scheduled E-DCH power share


E-DCH scheduling service consists of following two types:

TypeA: all UEs for which this cell is the serving E-DCH cell

The uplink load generated by TypeA E-DCH scheduling service is defined as follows:

ηUL − EDCH , S =

RSEPS RTWP

TypeB: all UEs for which this cell is

NOT the serving EDCH-cell

The uplink load generated by

TypeB E-DCH scheduling service is defined by ηUL,EDCH,f, which is fixed to zero

The Uplink uncontrollable load

Is defined as follows:

ηUL , non − ctrl = ηUL − ηUL , EDCH , s − ηUL , EDCH , f Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.


UL Power CAC for HSUPA Scheduling Services and HSUPA Non-Scheduling Services

z

RNC admits HSUPA scheduling service in either of the following cases

z

Formula 1,2 or 3 is fulfilled

Formula 4 is fulfilled

RNC admits HSUPA Non-scheduling service in either of the following cases

Formula 1,2 or 3 is fulfilled

Formula 4 and 5 are fulfilled


ThdL is the Low priority HSUPA user PBR threshold of the current cell ThdE is the Equal priority HSUPA user PBR threshold of the current cell ThdGE is the High priority HSUPA user PBR threshold of the current cell

ηHS-DPCCH is the value of the UL HS-DPCCH reserve factor parameter, which defines the factor of UL HS-DPCCH resource reserved ηthd is the cell UL admission threshold for specific type of service, that is UL threshold of Conv AMR service, UL threshold of Conv non_AMR service, UL threshold of other services or UL handover access service threshold


UL Power CAC for R99 service in HSPA cell

Uncontollable interference must be kept within a given range. The purpose is to ensure the stability of system and to prevent non-scheduling services and DCH services from seizing the resources of HSUPA services

ηUL , non − ctrl + ΔηUL + ηUL , cch + η HS − DPCCH < ηthd ηUL + ΔηUL + ηUL., cch + η HS − DPCCH < ηthd − total

RNC admits R99 services if formula 1 and 2 are fulfilled


ηthd-total is the UL total power threshold of the current cell ηthd is the cell UL admission threshold for specific type of service, that is UL threshold of Conv AMR service, UL threshold of Conv non_AMR service, UL threshold of other services or UL handover access service threshold

DL Power CAC for HSPA Cell (Algorithm1) z

DL Power incremental estimation for DCH RAB in HSPA cell is similar to the DCH RAB in R99 cell

z

DL Power incremental estimation for HSDPA RAB ΔPDL is made based on GBR, Ec/No, Non-orthogonality factor



DL power CAC for R99 service in HSPA cell

z

RNC admits R99 service (i.e. DCH RAB) in either of the following situations:




Pnon-hspa is the current non-HSDPA power Pcch-res is the power reserved for the common channel Pmax is the cell maximum transmit power Thdnon-hspa-cac is the cell DL admission threshold for different types of service, that is DL threshold for Conv AMR service, DL threshold for Conv non-AMR service, DL threshold for other service or DL handover access threshold Ptotal is the current downlink transmitted carrier power Thdtotal-cac is the threshold of cell DL total power. It is defined by the DL total power threshold parameter GBP is power requirement for GBR Phsupa-res is the power reserved for HSUPA downlink control channels (E-AGCH/E-RGCH/E-HICH) Pmax-hspa is the maximum available power for HSPA. Its value is associated with the HSDPA power allocation mode.


DL power CAC for HSDPA RAB in HSPA cell

z

RNC admits the HSDPA streaming service in any of the following situations:

z


Formulas 3 and 4 are fulfilled


RNC admits the HSDPA BE service in any of the following situations:





PBRstrm is the provided bit rate of all existing streaming services Thdhsdap-str is the admission threshold for streaming PBR decision. It is defined by the Hsdpa streaming PBR threshold parameter PBRbe is the provided bit rate of all existing BE services Thdhsdap-be is the admission threshold for BE PBR decision. It is defined by the Hsdpa best effort PBR threshold parameter GBR is the power requirement for GBR Phsupa-res is the power reserved for HSUPA downlink control channels (E-AGCH/E-RGCH/E-HICH) Pmax-hspa is the maximum available power for HSPA. Its value is associated with the HSDPA power allocation mode. Ptotal is the current downlink transmitted carrier power Pmax is the cell maximum transmitted power Thdtotal-cac is the threshold of cell DL total power, which is defined by the DL total power threshold parameter Pcch-res is the power reserved for the common channels Pnon-hspa is the current non-HSDPA power


DL power CAC for HSUPA control channels in HSPA cell

The power of downlink control channels (E-AGCH/E-RGCH/EHICH) are reserved by DL HSUPA reserved factor. Therefore, the power admission for these channels is NOT needed


Power CAC for Algorithm2 z

For R99 and HSDPA RAB, The RNC uses the following formula to predict the uplink load factor :

z

(ENUtotal + ENUnew) / ENUmax

By comparing the forecasted ENU load with the corresponding threshold ,the RNC decides whether to accept the access request or not


ENUtotal is the total ENU of all existing users. ENUnew is ENU of the new incoming user . ENUmax is the configured maximum ENU (UL total equivalent user number or DL total nonhsdpa equivalent user number) . The threshold for Algorithm2 are the same with Algorithm1,for Conv AMR service , Conv non_AMR service , Other R99 services , Handover , HSDPA are set independently:

Service Type

Admission Threshold

UL DCH/HSUPA

UL threshold of Conv AMR service UL threshold of Conv non_AMR service UL threshold of other services UL Handover access threshold

DL DCH

DL threshold of Conv AMR service DL threshold of Conv non_AMR service DL threshold of other services DL Handover access threshold

HSDPA

DL total power threshold

Typically ENU (equivalent number of users) for different services (with activity factor to be 100%)

Service Type

Admission Threshold

UL DCH/HSUPA

UL threshold of Conv AMR service UL threshold of Conv non_AMR service UL threshold of other services UL Handover access threshold

DL DCH

DL threshold of Conv AMR service DL threshold of Conv non_AMR service DL threshold of other services DL Handover access threshold

HSDPA


Key parameters z

z

UL threshold of Conv AMR service

Parameter ID: UlNonCtrlThdForAMR

The default value of this parameter is 75%

UL threshold of Conv non_AMR service

Parameter ID: UlNonCtrlThdForNonAMR



UL threshold of Conv AMR service Parameter ID: UlNonCtrlThdForAMR Value range: 0 to 100 % Content: The uplink threshold for the AMR conversational service is used for the uplink admission of AMR conversational service users. The threshold is shared by algorithm 1, algorithm 2 and algorithm 3. The default value of this parameter is 75% Set this parameter through ADD CELLCAC / MOD CELLCAC UL threshold of Conv non_AMR service Parameter ID: UlNonCtrlThdForNonAMR Value range: 0 to 100 % Content: The downlink threshold for the AMR conversational service is used for the downlink admission of AMR conversational service users. The threshold is shared by algorithm 1, algorithm 2 and algorithm 3. The default value of this parameter is 75% Set this parameter through ADD CELLCAC / MOD CELLCAC

Key parameters z

z

UL threshold of other services

Parameter ID: UlNonCtrlThdForOther


UL Handover access threshold

Parameter ID: UlNonCtrlThdForHo



UL threshold of other services Parameter ID: UlNonCtrlThdForOther Value range: 0 to 100 % Content: This parameter is the uplink threshold for services other than the conversational service. It is used for uplink admission of other services. The threshold is shared by algorithm 1, algorithm 2 and algorithm 3. The default value of this parameter is 60% Set this parameter through ADD CELLCAC / MOD CELLCAC UL Handover access threshold Parameter ID: UlNonCtrlThdForHo Value range: 0 to 100 % Content: The uplink handover threshold is used for uplink admission of handover users. The parameter is useful only to uplink inter-frequency handovers. Do not make the admission decision in the uplink soft handover. The threshold is shared by algorithm 1, algorithm 2 and algorithm 3. The default value of this parameter is 80% Set this parameter through ADD CELLCAC / MOD CELLCAC

Key parameters z

z

DL threshold of Conv AMR service

Parameter ID: DLCONVAMRTHD


DL threshold of Conv non_AMR service

Parameter ID: DLCONVNAMRTHD



DL threshold of Conv AMR service Parameter ID: DLCONVAMRTHD Value range: 0 to 100 % Content: The downlink threshold for the AMR conversational service is used for the downlink admission of AMR conversational service users. The threshold is shared by algorithm 1, algorithm 2 and algorithm 3. The default value of this parameter is 80% Set this parameter through ADD CELLCAC / MOD CELLCAC DL threshold of Conv non_AMR service Parameter ID: DLCONVNAMRTHD Value range: 0 to 100 % Content: The downlink threshold for the non-AMR conversational service is used for the downlink admission of non-AMR conversational service users. The threshold is shared by algorithm 1, algorithm 2 and algorithm 3. The default value of this parameter is 80% Set this parameter through ADD CELLCAC / MOD CELLCAC

Key parameters z

z

DL threshold of other services

Parameter ID: DLOTHERTHD


DL Handover access threshold

Parameter ID: DLHOTHD



DL threshold of other services Parameter ID: DLOTHERTHD Value range: 0 to 100 % Content: This parameter is the downlink threshold for services other than the conversational service. It is used for downlink admission of users of other services. The threshold is shared by algorithm 1, algorithm 2 and algorithm 3. The default value of this parameter is 75% Set this parameter through ADD CELLCAC/MOD CELLCAC DL Handover access threshold Parameter ID: DLHOTHD Value range: 0 to 100 % Content: The downlink handover threshold is used for downlink admission of handover users. The threshold is shared by algorithm 1, algorithm 2 and algorithm 3. The default value of this parameter is 85% Set this parameter through ADD CELLCAC / MOD CELLCAC

Key parameters z

z

z


Parameter ID: DLCELLTOTALTHD


Hsdpa streaming PBR threshold

Parameter ID: HSDPASTRMPBRTHD


Hsdpa best effort PBR threshold

Parameter ID: HSDPABEPBRTHD



DL total power threshold Parameter ID: DLCELLTOTALTHD Value range: 0 to 100 % Content: This parameter specifies the total downlink power threshold of the cell. The default value of this parameter is 90% Set this parameter through ADD CELLCAC / MOD CELLCAC Hsdpa streaming PBR threshold Parameter ID: HSDPASTRMPBRTHD Value range: 0 to 100 % Content: This parameter specifies the average throughput admission threshold of the HSDPA streaming traffic. The default value of this parameter is 70% Set this parameter through ADD CELLCAC / MOD CELLCAC Hsdpa streaming PBR threshold Parameter ID: : HSDPABEPBRTHD Value range: 0 to 100 % Content: This parameter specifies the average throughput admission threshold of the HSDPA best effort traffic. The default value of this parameter is 70% Set this parameter through ADD CELLCAC / MOD CELLCAC

Key parameters z

z

UL total equivalent user number

Parameter ID: ULTOTALEQUSERNUM


DL total equivalent user number

Parameter ID: DLTOTALEQUSERNUM



UL total equivalent user number Parameter ID: ULTOTALEQUSERNUM Value range: 1 to 200 Content: When algorithm 2 is used, this parameter defines the total equivalent number of users corresponding to the 100% uplink load. The default value of this parameter is 80 Set this parameter through ADD CELLCAC/MOD CELLCAC DL total equivalent user number Parameter ID: DLTOTALEQUSERNUM Value range: 1 to 200 Content: When algorithm 2 is used, this parameter defines the total equivalent number of users corresponding to the 100% downlink load. The default value of this parameter is 80 Set this parameter through ADD CELLCAC / MOD CELLCAC

CAC Based on NodeB Credit Resource z

When a new service accesses the network, NodeB credit resource admission is optional

z

The principles of NodeB credit admission control are similar to those of power resource admission control, that is, to check in the local cell whether the remaining credit can support the requesting services


CE stands for NodeB credit on RNC side and for Channel Element on NodeB side. It is used to measure the channel demodulation capability of the NodeBs The resource of one 12.2kbps voice service, including 3.4kbps signaling on the DCCH, consumed in baseband is defined as one CE. If there is 3.4kbps signaling on the DCCH, but no voice channel, one CE is consumed.The credit resource are divided into several resource pools. Each resource pool is shared by a local cell. According to the common and dedicated channels capacity consumption laws, as well as the addition, removal, and reconfiguration of the common and dedicated channels, the Controlling RNC (CRNC) debits the amount of the credit resource consumed from or credits the amount to the Capacity Credit of the local cell group (and local cell , if any) based on the spreading factor. the UL Capacity Credit and DL Capacity Credit are separate, so the CAC is performed in the UL and DL, respectively.


For DCH service, MBR is used to calculate the NodeB Credit based on spreading factor :

z

The total NodeB Credit Resource of a local cell is depend on the configuration.


Direction

Spreading Factor

Corresponding Credits Consumed

DL

256

1

UL

256

2

DL

128

1

UL

64

2

DL

128

1

UL

64

2

DL

32

2

UL

16

6

DL

64

1

UL

32

3

DL

32

2

UL

16

6

DL

16

4

UL

8

10

DL

8

8

UL

4

20

Typical Traffic Class

3.4 kbit/s SRB

13.6 kbit/s SRB

12.2 kbit/s AMR

64 kbit/s VP

32 kbps PS

64 kbit/s PS

128 kbit/s PS

384 kbit/s PS


For HSUPA service, the rate used to calculate the spreading factor is MBR



When a new service tries to access the network, the credit resource admission CAC functions in :


Handover service

The other services


For an RRC connection setup request, the credit resource admission is successful if the current remaining credit resource is sufficient for the RRC connection. For a handover service, the credit resource admission is successful if the current remaining credit resource is sufficient for the service. For other services, the RNC has to ensure that the remaining credit does not exceed the configurable thresholds after admission of the new services. There is no capacity consumption law for HS-DSCH in 3GPP TS 25.433, so certain credits are reserved for HSDPA RAB, and credit admission for HSDPA is not needed. UL Capacity Credit and DL Capacity Credit are separate, the credit resource admission is implemented in the UL and DL, respectively.

Key parameters z

z

Ul HandOver Credit Reserved SF

Parameter ID: UlHoCeResvSf

The default value of this parameter is SF16

Dl HandOver Credit and Code Reserved SF

Parameter ID: DlHoCeCodeResvSf



Ul HandOver Credit Reserved SF Parameter ID: UlHoCeResvSf Value range: SF4, SF8, SF16, SF32, SF64, SF128, SF256, SFOFF Content: The spreading factor specified by this parameter is used to define the uplink credit resource reserved for handover services. SFOFF means that none of resources are reserved for handover services. If the remaining uplink resource cannot fulfill the requirement for the reserved resource after the admission of a new service, the service is rejected. The default value of this parameter is SF16 Set this parameter through ADD CELLCAC / MOD CELLCAC Dl HandOver Credit and Code Reserved SF Parameter ID: DlHoCeCodeResvSf Value range: SF4, SF8, SF16, SF32, SF64, SF128, SF256, SFOFF Content: The spreading factor specified by this parameter is used to define the downlink credit and channelized code resources reserved for handover services. SFOFF means that none of the resources is reserved for handover. If the remaining downlink resource cannot fulfill the requirement for the reserved resource after the access of a new service, the service is rejected. The default value of this parameter is SF32 Set this parameter through ADD CELLCAC / MOD CELLCAC

CAC Based on Iub Interface Resource z

The CAC of the Iub transmission resources is similar

z

Admission Control is used to determine whether the Iub resources are enough to accept a new access request

z

It functions in:

RRC connection setup and Services RAB setup

Handover


A user accessing the network from a path should go through the admission of the path, resource group, and physical port in turn. The user that passes all the admission can be successfully admitted by the transport layer. Path means AAL2 PATH, IP PATH The physical ports correspond to IMA, UNI, FRAATM, NCOPT, ETHER, PPP, and MLPPP. The priority of the 2 types of access follows : Handover >RRC connection setup and Services RAB setup


Iub Overbooking

The Iub overbooking feature considers the statistic multiplexing of service activities and multiple users

Admit more users, increases the resource utilization on the Iub interface.


The Iub overbooking feature considers the statistic multiplexing of service activities and multiple users. Through the admission of more users, Iub overbooking increases the resource utilization on the Iub interface. If the RNC allocates the maximum bandwidth to the subscriber when a service is established, a large proportion of the Iub transmission bandwidth is unused. For example, downloading a 50 KB page takes only about one second, but reading this page needs dozens of seconds. Thus, over 90% of the Iub transmission bandwidth is not used. To save the Iub transmission bandwidth for operator use, Huawei provides the Iub overbooking function, which applies an admission control mechanism to access the service.


Iub Overbooking

CS voice services

Service rate:12.2 kbit/s

SID

PS interactive and background services

Download time

Reading time


The UMTS supports four traffic classes: conversational, streaming, interactive, and background. The transmission rate varies with the traffic class as follows: For Circuit Switched (CS) conversational services, the channel transmits voice signals at a certain rate (for example, 12.2 kbit/s) during a conversation and only transmits Silence Descriptors (SIDs) at intervals when there is no conversation. For Packet Switched (PS) interactive and background services, such as web browsing, there is data transmitted during data downloading. After a web page has been downloaded, and when the user is reading the page, however, there is very little data to transfer.


Iub Overbooking

CS voice services

PS interactive and background services

Activity Factor

GBR

MML SET DEFAULTFACTORTABLE SET USERGBR SET CORRMALGOSWITCH (IUB_OVERBOOKING_SWITCH) ADD AAL2PATH ADD IPPATH


Use SET DEFAULTFACTORTABLE to set a default of Activity Factor table for all the services. Use SET USERGBR to set GBR for BE services Use SET CORRMALGOSWITCH (IUB_OVERBOOKING_SWITCH) to define the switch of Iub overbooking

CAC Based on Number of HSPA Users z

HSPA user number can be limited in:

z

Cell level

z

maximum number of HSPA users in a cell

NodeB level

Maximum number of HSPA users in all the cells configured in one NodeB


When the HSDPA_UU_ADCTRL is on, the HSDPA services have to undergo HSDPA user number admission decision. When a new HSDPA service attempts to access the network, it is admitted if the number of HSDPA users in the cell and that in the NodeB do not exceed the associated thresholds When the HSUPA_UU_ADCTRL is on, the HSUPA services have to undergo HSUPA user number admission decision. When a new HSUPA service attempts to access the network, it is admitted if the number of HSUPA users in the cell and that in the NodeB do not exceed the associated thresholds

Key parameters z

HSDPA_UU_ADCTRL

z

z

Maximum HSDPA user number

Parameter ID: MaxHSDSCHUserNum


HSDPA_UU_ADCTRL

z

Parameter ID: HSDPA_UU_ADCTRL

Parameter ID: HSUPA_UU_ADCTRL

Maximum HSUPA user number

Parameter ID: MaxHsupaUserNum



Maximum HSDPA user number Parameter ID: MaxHSDSCHUserNum Value range: 0 to 100 Content: This parameter specifies the maximum number of HSDPA users in a cell. The default value of this parameter is 64 Set this parameter through ADD CELLCAC/MOD CELLCAC HSDPA_UU_ADCTRL Parameter ID: HSDPA_UU_ADCTRL Value range: 0 ,1 Content: This parameter specifies whether to enable or disable the HSDPA admission control algorithm. Set this parameter through ADD CELLALGOSWITCH / LST CELLALGOSWITCH/MOD CELLALGOSWITCH HSUPA_UU_ADCTRL Parameter ID: HSDPA_UU_ADCTRL Value range: 0 ,1 Content: This parameter specifies whether to enable or disable the HSDPA admission control algorithm. Set this parameter through ADD CELLALGOSWITCH / LST CELLALGOSWITCH/MOD CELLALGOSWITCH Maximum HSUPA user number Parameter ID: MaxHsupaUserNum Value range: 0 to 100 Content: This parameter specifies the maximum number of HSDPA users in a cell. The default value of this parameter is 20 Content: This parameter specifies the maximum number of HSUPA users in a cell. Set this parameter through ADD CELLCAC / LST CELLCAC / MOD CELLCAC



Why we need IAC? z

z

The disadvantage of CAC

For PS NRT (Non-Real Time) services, CAC is not flexible

No consideration about the priority of different users

No consideration about Directed Retry after CAC rejection

“Intelligent” means the algorithm can increase admission successful rate


CAC limits the setup of RRC and RAB . When the cell is overloaded , the CAC will cause access failure. In order to improve the access success rate the Intelligent Access Control (IAC) algorithm is used to improve the access success rate. The IAC procedure includes rate negotiation, Call Admission Control (CAC), preemption, queuing, and Directed Retry Decision (DRD).

IAC Overview z

The access procedure (include the IAC)


As shown in the Figure, the procedure for the UE access includes the procedures for RRC connection setup and RAB setup. The success in the RRC connection setup is one of the prerequisites for the RAB setup. During the RRC connection processing, if resource admission fails, DRD and redirection apply. During the RAB processing, the RNC performs the following steps: • Performs RAB DRD to select a suitable cell to access, for service steering or load balancing. • Performs rate negotiation according to the service requested by the UE. • Performs cell resource admission decision. If the admission is passed, UE access is granted. Otherwise, the RNC performs the next step. • Selects a suitable cell, according to the RAB DRD algorithm, from the cells where no admission attempt has been made, and then goes to rate negotiation and cell resource admission again. If all DRD admission attempts to the cells fail, go to the next step. • Makes a preemption attempt. If the preemption is successful, UE access is granted. If the preemption fails or is not supported, the RNC performs the next step, queuing. • Makes a queuing attempt. If the queuing is successful, UE access is granted. If the queuing fails or is not supported, the RNC Rejects UE access.

IAC - RRC Connection Processing


When a new service accesses the network, an RRC connection must be set up first. If the RRC connection request is denied, DRD is performed. If DRD also fails, RRC redirection is performed to direct the UE to an inter-frequency or inter-RAT cell through cell reselection. After the RNC receives the RRC CONNECTION REQUEST message, the CAC algorithm decides whether an RRC connection can be set up between the UE and the current cell. If the RRC connection can be set up between the UE and the current cell, the RNC sends an RRC CONNECTION SETUP message to the UE. If the RRC connection cannot be set up between the UE and the current cell, the RNC takes the following actions: RRC DRD : If the DRD_SWITCH is set to 0, the RRC DRD fails, and RRC redirection is performed. Else, the RNC performs the following steps: 1. The RNC selects inter-frequency neighboring cells of the current cell. These neighboring cells are suitable for blind handovers. 2. The RNC generates a list of candidate DRD-supportive inter-frequency cells. The quality of the candidate cell meets the requirements of inter-frequency DRD: (CPICH_Ec/No)RACH > DRD_Ec/No nbcell where (CPICH_Ec/No)RACH is the cached CPICH Ec/N0 value included in the RACH measurement report. DRD_Ec/No nbcell is the DRD Ec/N0 Threshold set for the inter-frequency neighboring cell.

3. RNC selects a target cell from the candidate cells for UE access. If the candidate cell list contains more than one cell, the UE tries a cell randomly. 1. If the admission is successful, the RNC initiates an RRC DRD procedure. 2. If the admission to a cell fails, the UE tries admission to another cell in the candidate cell list. If all the admission attempts fail, the RNC makes an RRC redirection decision. 4. If the candidate cell list does not contain any cell, the RRC DRD fails. The RNC performs the next step, that is, RRC redirection. 5. RRC redirection, the RNC performs the following steps: 1. The RNC selects all inter-frequency cells of the local cell. 2. The RNC selects candidate cells. That is, exclude the cells to which inter-frequency RRC DRD attempts have been made from the cells selected in the previous step. 3. If more than one candidate cell is available, the RNC selects a cell randomly and redirects the UE to the cell.

Key parameters z

RRC redirect switch

Parameter ID: RrcRedictSwitch

The default value of this parameter is Only_To_Inter_Frequency

z

DRD Ec/N0 threshold

Parameter ID: DRDEcN0Threshhold

The default value of this parameter is -18（-9 dB）


RRC redirect switch Parameter ID: RrcRedictSwitch Value range: OFF, Only_To_Inter_Frequency, Allowed_To_Inter_RAT Content: This parameter specifies the RRC redirection strategy. The default value of this parameter is Only_To_Inter_Frequency Set this parameter through SET DRD DRD Ec/N0 threshold Parameter ID: DRDEcN0Threshhold Value range: –24 to 0 Content: If the measured Ec/N0 value of the neighbor cell is less than this parameter, this neighboring cell cannot be selected to be the candidate DRD cell. The default value of this parameter is -18（-9 dB） Set this parameter through ADD INTERFREQNCELL

IAC – PS Rate Negotiation z

PS Service Rate Negotiation Includes:

Maximum expected rate negotiation

Initial rate negotiation

Target rate negotiation


Rate negotiation includes the maximum expected rate negotiation, initial rate negotiation, and target rate negotiation. When setting up, modifying, or admitting a PS service (conversational, streaming, interactive, or background service) the RNC and the CN negotiate the rate according to the UE capability to obtain the maximum expected rate while ensuring a proper QoS. For a non-real-time service in the PS domain, the RNC selects an initial rate to allocate bandwidth for the service when Setup or UE state transits from CELL_FACH to CELL_DCH based on cell code and credit resource The Initial rate selection is affected by 2 algorithm switches: RAB Downsizing Switch, DCCC Switch For DCH

For HSUPA

For a non-real-time service in the PS domain, if cell resource admission fails, the RNC chooses a target rate to allocate bandwidth for the service based on cell resource in Service setup or Soft handover

Key parameters z

z

RAB_Downsizing_Switch

Parameter ID: RAB_DOWNSIZING_SWITCH

The default value of this parameter is 1 (on)

UL/DL BE traffic Initial bit rate

Parameter ID:

ULBETRAFFINITBITRATE / DLBETRAFFINITBITRATE

The default value of this parameter is D64 （64k）


RAB_Downsizing_Switch Parameter ID: RAB_DOWNSIZING_SWITCH Value range: (0,1) Content: This parameter specifies whether to support the RAB downsizing function. The default value of this parameter is 1 (on) When this parameter is set to 1, the RAB downsizing function is applied to determine the initial bit rate based on cell resources (code and credit). . Set this parameter through SET CORRMALGOSWITCH UL/DL BE traffic Initial bit rate Parameter ID: ULBETRAFFINITBITRATE / DLBETRAFFINITBITRATE Value range: D8, D16, D32, D64, D128, D144, D256, D384, D768, D1024, D1536, D1800, D2048 k Content: This parameter defines the uplink initial access rate of background and interactive services in the PS domain. The default value of this parameter is D64 （64k） Set this parameter through SET FRC

IAC – RAB Directed Retry Decision z

RAB Directed Retry Decision (DRD) is used to select a suitable cell for the UE to try an access

Inter-frequency DRD

Service Steering

Load Balancing

Inter-RAT DRD


Through the RAB DRD procedure, the RNC selects a suitable cell for RAB processing during access control. RAB DRD is of two types: inter-frequency DRD and inter-RAT DRD. For inter-frequency DRD, the service steering and load balancing algorithms are available. After receiving a RANAP RAB ASSIGNMENT REQUEST, the RNC initiates an RAB DRD procedure to select a suitable cell for RAB processing during access control. The RNC performs inter-frequency DRD firstly. If all admission attempts of interfrequency DRD fail, the RNC performs an inter-RAT DRD. If all admission attempts of inter-RAT DRD fail, the RNC selects a suitable cell to perform preemption and queuing . Relation Between Service Steering DRD and Load Balancing DRD When both service steering DRD and load balancing DRD are enabled, the general principles of inter-frequency DRD are as follows: •

Service steering DRD takes precedence over load balancing DRD. That is, preferably take service priorities into consideration.

•

To services of the same service priority, load balancing applies.

IAC – RAB Directed Retry Decision RAB Directed Retry Switchs Scenario

Switch

Description

DRD switch

DRD_SWITCH

This is the primary DRD algorithm switch. The secondary DRD switches are valid only when this switch is on.

Combined services

COMB_SERV_DRD_SWITCH

DRD is applicable to combined services only when this switch is on.

HSDPA service

HSDPA_DRD_SWITCH

DRD is applicable to HSDPA services only when this switch is on.

HSUPA service

HSUPA_DRD_SWITCH

DRD is applicable to HSUPA services only when this switch is on.

RAB modification

RAB_MODIFY_DRD_SWITCH

DRD is applicable to RAB modification only when this switch is on.

DCCC

RAB_DCCC_DRD_SWITCH

DRD is applicable to traffic-volume-based DCCC procedure or UE state transition, only when this switch is on.

RAB setup

RAB_SETUP_DRD_SWITCH

DRD is applicable to RAB setup only when this switch is on.

DRD algorithm switch Parameter ID: DRDSWITCH The default value of this parameter is off Set this parameter through SET CORRMALGOSWITCH

IAC – Inter-frequency DRD z

Inter-Frequency DRD for Service Steering

DRD for Service Steering is based on Service priorities of cells ,include: – R99 RT services priority – R99 NRT services priority – HSPA services priority – Other services priority

Called Service priority group


If the UE requests a service in an area covered by multiple frequencies, the RNC selects the cell with the highest service priority for UE access, based on the service type of RAB and the definitions of service priorities in the cells. Cell service priorities help achieve traffic absorption in a hierarchical way. The priorities of specific service types in cells are configurable. If a cell does not support a service type, the priority of this service type is set to 0 in this cell. The service priorities in each cell is called Service priority group , which is identified by the Service priority group Identity parameter. Service priority groups are configured on the LMT. In each group, priorities of R99 RT services, R99 NRT services, HSPA services, and other services are defined. When selecting a target cell for RAB processing, the RNC check the service type firstly , then, selects a cell with a high priority for the service, that is, a cell that has a small value of service priority.


Inter-Frequency DRD for Service Steering Service priority group Identity

Service priority

Service priority

Service priority

service

service

service

1

2

1

1

0

2

1

2

0

0

An example priority group of R99 RT of service of R99 NRT of HSPA

Service priority of other service


Cell A and cell B are of different frequencies. Assume that the service priority groups given in the table are defined on an RNC, 2 groups of service priorities are defined. Then ,Cell A is configured with service priority group 1. Cell B is configured with service priority group 2 If UE requests a R99 RT service in cell A ,Cell B has a higher service priority of the R99 RT service than cell A. If the UE requests an RT service in cell A, preferably, the RNC selects cell B for the UE to access.


Inter-Frequency DRD procedure for Service Steering


The procedure for the service steering DRD is as follows: 1、The RNC determines candidate cells to which blind handovers can be performed and sorts the candidate cells into a descending order according to service priority. A candidate cell must meet the following conditions: •

The frequency of the candidate cell is within the band supported by the UE.

•

The quality of the candidate cell meets the Ec/No requirements of inter-frequency DRD (DRD Ec/N0 Threshold )

•

The candidate cell supports the requested service.

2、The RNC selects a target cell from the candidate cells in order of service priority for UE access. 3、The CAC algorithm makes an admission decision based on the status of the target cell. •

If the admission attempt is successful, the RNC accepts the service request.

•

If the admission attempt fails, the RNC removes the cell from the candidate cells and then choose next candidate cell.

4、If admission decisions have been made in all the candidate cells •

For HSPA access, the HSPA request falls back to a DCH one. Then, the algorithm goes back to Step 1 to make an admission decision based on R99 service priorities.

•

For DCH access, the RNC initiates an inter-RAT DRD.

Key parameters z

z

Service differential drd switch

Parameter ID: ServiceDiffDrdSwitch


Service priority group Identity

Parameter ID: PriorityServiceForR99RT


Service differential drd switch Parameter ID: ServiceDiffDrdSwitch Value range: ON, OFF Content: This parameter specifies whether to enable the service steering DRD algorithm The default value of this parameter is OFF. Set this parameter through ADD CELLDRD Service priority of R99 RT service Parameter ID: SpgId Value range: 1 to 8 Content: This parameter uniquely identifies a group of service priorities that map to cells and indicate the support of each cell for the following service types: R99 RT service, R99 NRT service, HSPA service, and other services. Set this parameter through ADD SPG

Key parameters z

Service priority of R99 RT service

z

Service priority of R99 NRT service

z

PriorityServiceForR99NRT

Service priority of HSPA service

z

Parameter ID: SpgId

PriorityServiceForHSPA

Service priority of Other service

PriorityServiceForExtRab


Service priority of R99 RT service Parameter ID: PriorityServiceForR99RT Value range: 0 to 7 Content: This parameter specifies the support of the cells with a specific Service priority group Identity for R99 RT services. The value 0 means that these cells do not support R99 RT services. For the values 1 through 7, the service priority is inversely proportional to the value, that is, the value 7 indicates the lowest service priority, whereas the value 1 indicates the highest. Set this parameter through ADD SPG

Service priority of R99 NRT service Parameter ID: PriorityServiceForR99NRT Value range: 0 to 7 Content: This parameter specifies the support of the cells with a specific Service priority group Identity for R99 NRT services. The value 0 means that these cells do not support R99 NRT services. For the values 1 through 7, the service priority is inversely proportional to the value, that is, the value 7 indicates the lowest service priority, whereas the value 1 indicates the highest. Set this parameter through ADD SPG Service priority of HSPA service Parameter ID: PriorityServiceForHSPA Value range: 0 to 7 Content: This parameter specifies the support of the cells with a specific Service priority group Identity for HSPA services. The value 0 means that these cells do not support HSPA services. For the values 1 through 7, the service priority is inversely proportional to the value, that is, the value 7 indicates the lowest service priority, whereas the value 1 indicates the highest. Set this parameter through ADD SPG Service priority of Other service Parameter ID: PriorityServiceForExtRab Value range: 0 to 7 Content: This parameter specifies the support of the cells with a specific Service priority group Identity for Other services . The value 0 means that these cells do not support Other service . For the values 1 through 7, the service priority is inversely proportional to the value, that is, the value 7 indicates the lowest service priority, whereas the value 1 indicates the highest. Set this parameter through ADD SPG


Inter-Frequency DRD for Load Balance

The resources triggering DRD for Load Balance include:

DL Power

OVSF code

Any of these 2 resources can trigger inter-frequency DRD for Load Balance


Load balancing considers two resources: power, and code. If both are activated, power-based load balancing DRD takes precedence over codebased load balancing DRD. Code-based load balancing DRD is applicable to only R99 services because HSDPA services use reserved codes.


Inter-Frequency DRD procedure for DL Power Load Balance


The procedure for the service steering DRD is as follows: 1、The RNC determines candidate cells to which blind handovers can be performed and sorts the candidate cells into a descending order according to service priority. A candidate cell must meet the following conditions: • The frequency of the candidate cell is within the band supported by the UE. • The quality of the candidate cell meets the Ec/No requirements of inter-frequency DRD (DRD Ec/N0 Threshold ) • The candidate cell supports the requested service. 2、The RNC determines whether the DL radio load of the current cell is lower than the power threshold for load balancing DRD (condition 1 ) power threshold for load balancing DRD is CAC parameter. •If the DL load of the current cell is lower than the threshold, the service tries admission to the current cell. •If the DL load of the current cell is equal to or higher than the threshold, the RNC checks the candidate cells to try to find out a target cell for UE access. RNC will check if there is a candidate cell will meet the following condition (condition 2 ) :

•Ptotal_thd,nbcell is DL total power threshold for the inter-frequency neighboring cell. •Pload,nbcell is total power load of the inter-frequency neighboring cell. For a R99 cell, it is the Downlink Transmitted Carrier Power of the cell, and for an HSPA cell, it is the nonHSDPA power and GBP. •Ptotal_thd,cutcell is DL total power threshold for the current cell. •Pload,cutcell is the total downlink load of the current cell. •Ploadoffset is the Power balancing drd offset of the current cell.

Then, the RNC selects the target cell as follows: • If there is only one inter-frequency neighboring cell that meets the load balancing DRD conditions, the RNC selects this cell as the target cell. • If there are multiple such cells, the RNC selects the cell with the lightest load as the target cell. • If there is no such cell, the RNC selects the current cell as the target cell. 3、The CAC algorithm makes an admission decision based on the status of the target cell. • If the admission attempt is successful, the RNC accepts the service request. • If the admission attempt fails, the RNC removes the cell from the candidate cells and then choose next candidate cell. 4、If admission decisions have been made in all the candidate cells •For HSPA access, the HSPA request falls back to a DCH one. Then, the algorithm goes back to Step 1 to make an admission decision based on R99 service priorities. •For DCH access, the RNC initiates an inter-RAT DRD.

Key parameters z

z

z

z

z

Power balance DRD switch on DCH

Parameter ID: LdbDrdSwitchDCH


Power balance DRD switch on HSDPA

Parameter ID: LdbDrdSwitchHSDPA


Max transmit power of cell

Parameter ID: MaxTxPower

The default value of this parameter is 430 (43dBm)

Dl power balancing drd power threshold for DCH

Parameter ID: LdbDRDOffsetDCH


Dl power balancing drd power threshold for HSDPA

Parameter ID: LdbDRDOffsetHSDPA



Power balancing drd switch Parameter ID: PowerBalancingDrdSwitch Value range: ON, OFF Content: This parameter specifies whether to enable the power-based load balancing DRD algorithm . The default value of this parameter is OFF. Set this parameter through SET DRD / ADD CELLDRD Max transmit power of cell Parameter ID: MaxTxPower Value range: 0 to 500 , step:0.1dBm Content: This parameter specifies the sum of the maximum transmit power of all the downlink channels in a cell. The default value of this parameter is 430 (43dBm). Set this parameter through MOD CELL Power balancing drd offset Parameter ID: LoadBalanceDRDOffset Value range: 0% to 100% Content: This parameter specifies the load offset threshold of the current cell and the inter-frequency cell when power balancing drd algorithm is applied. Only when the cell load offset reaches this threshold, the inter-frequency cell can be selected to be the target drd cell. The default value of this parameter is 10% Set this parameter through SET DRD / ADD CELLDRD


Inter-Frequency DRD procedure for Code Load Balance


The procedure of load balancing DRD based on code resource is similar to that based on power resource. 1、The RNC determines whether the minimum remaining spreading factor of the current cell is smaller than Minimum SF threshold for code balancing drd. •

If the minimum SF is smaller than Minimum SF threshold for code balancing drd, the RNC tries the admission of the service request to the current cell.

•

If the minimum SF is not smaller than Minimum SF threshold for code balancing drd, the RNC performs the next step .

2、The RNC determines whether the code load of the current cell is lower than Code occupied rate threshold for code balancing drd. . •

If the code load is lower than Code occupied rate threshold for code balancing drd, the service tries the admission to the current cell.

•

If the code load is not lower than Code occupied rate threshold for code balancing drd, the RNC selects the cell with the lightest code load or the current cell as the target cell.

3、The RNC selects the cell as follows: •

If the difference between the code resource occupancies of the cell and the current cell is larger than the value of Delta code occupied rate , the RNC selects the cell with the lightest code load as the target cell. Otherwise, the RNC selects the current cell as the target cell.

Key parameters z

z

Code balancing drd switch

Parameter ID: CodeBalancingDrdSwitch


Minimum SF threshold for code balancing drd

Parameter ID: CodeBalancingDrdMinSFThd



Code balancing drd switch Parameter ID: CodeBalancingDrdSwitch Value range: ON, OFF Content: This parameter specifies whether to enable the code-based load balancing DRD algorithm. The default value of this parameter is OFF. Set this parameter through SET DRD / ADD CELLDRD Minimum SF threshold for code balancing drd Parameter ID: CodeBalancingDrdMinSFThd Value range: SF4, SF8, SF16, SF32, SF64, SF128, SF256 Content: If the downlink minimum SF of the best cell is below this threshold, the code-based load balancing DRD is not triggered. The default value of this parameter is SF8 . Set this parameter through SET DRD / ADD CELLDRD

Key parameters z

z

Code occupied rate threshold for code balancing drd

Parameter ID: CodeBalancingDrdCodeRateThd


Delta code occupied rate

Parameter ID: DeltaCodeOccupiedRate



Code occupied rate threshold for code balancing drd Parameter ID: CodeBalancingDrdCodeRateThd Value range: 0% to 100% Content: This parameter specifies the code occupancy threshold of the current cell for code-based load balancing DRD.Only when the code occupancy of the best cell reaches this threshold can code-based load balancing DRD be triggered. The default value of this parameter is 13%. Set this parameter through SET DRD / ADD CELLDRD Delta code occupied rate Parameter ID: DeltaCodeOccupiedRate Value range: 0% to 100% Content: This parameter specifies the code occupied rate offset threshold of the current cell and the inter-frequency cell when code balancing drd algorithm is applied. Only when the code occupied rate offset reaches this threshold, the inter-frequency cell can be selected to be the target drd cell. The default value of this parameter is 7% . Set this parameter through SET DRD

IAC – Inter-RAT DRD z

Inter-RAT DRD

Inter-RAT DRD is available for AMR service only in RAN 10:


The inter-RAT DRD procedure is as follows: 1,If the current cell is configured with any neighboring GSM cell suitable for blind handover and the Service Handover Indicator is set to HO_TO_GSM_SHOULD_BE_PERFORM, the RNC performs next step. Otherwise, the service request undergoes preemption and queuing. 2,The RNC generates a list of candidate DRD-supportive inter-RAT cells that fulfill the Ec/No threshold. 3,The service request then tries admission to a target GSM cell in order of blind handover priority. 4,If all admission attempts fail or the number of inter-RAT directed retries exceeds the value of Max inter-RAT direct retry number, the service request undergoes preemption and queuing.

Key parameters z

Max inter-RAT direct retry number

Parameter ID: DRMaxGSMNum



Max inter-RAT direct retry number Parameter ID: DRMaxGSMNum Value range: 0 to 5 Content: This parameter defines the maximum number of inter-RAT directed retries for an RAB. The value 0 means that inter-RAT DRD is not allowed. The default value of this parameter is 2 Set this parameter through ADD CELLDRD

IAC – Preemption and Queuing z

After cell admission fails, the RNC performs preemption and Queuing

Precondition of Preemption and Queuing – According to CN setting, Preemption and Queuing is supported

Target cell of Preemption and Queuing – Based on DRD


Preemption and Queuing guarantees the success in the access of a higher-priority user by forcibly releasing the resources of a lower-priority user. After cell resource admission fails, the RNC performs Preemption and Queuing if the following conditions are met: The RNC receives an RAB ASSIGNMENT REQUEST message indicating that Preemption and Queuing is supported. By default, Preemption and Queuing setting in CN may be: USER LEVEL

Preemption capability

Preemptable

Queuing

High

Able

Not allowed

allowed

Medium

Able

allowed

allowed

Low

Not able

allowed

Not allowed

Preemption and Queuing is applicable to the following cases: Setup or modification of a service Hard handover or SRNS relocation UE state transits from CELL_FACH to CELL_DCH The RNC selects a suitable cell according to the settings of the DRD algorithms.

IAC – Preemption z

Preemption on different resources Service

Resource

Service That can Be Preempted R99 Service

R99 service

HSDPA service

HSDPA Service

R99 + HSPA Combined Service

Code

√

-

√

Power

√

√

√

CE

√

-

√

Iub bandwidth

√

√

√

Code

-

-

-

Power

√

√

√

CE

-

-

-

Iub bandwidth

√

√

√

Number of users

-

√

√


The preemption procedure is as follows: 1、The preemption algorithm determines which radio link sets can be preempted. The algorithm proceeds as follows: Chooses SRNC users first. If no user under the SRNC is available, the algorithm chooses users under the DRNC. Sorts the pre-emptable users by user integrate priority, or sorts the preemptable RABs by RAB integrate priority. Determines candidate users or RABs. Only the users or RABs with priorities lower than the RAB to be established are selected. Selects as many users or RABs as necessary in order to match the resource needed by the RAB to be established. When the priorities of two users or RABs are the same, the algorithm chooses the user or RAB that can release the most resources. 2、The RNC releases the resources occupied by the candidate users or RABs. 3、The requested service directly uses the released resources to access the network without admission decision.

Key parameters z

Preempt algorithm switch

Parameter ID: PREEMPTALGOSWITCH



Preempt algorithm switch Parameter ID: PREEMPTALGOSWITCH Value range: ON, OFF Content: This parameter specifies whether to support the preemption function. The default value of this parameter is OFF Set this parameter through SET QUEUEPREEMPT

IAC – Queuing z

After Preemption rejection, UE can wait in queue, then admission attempts for the service are made periodically till Tmax expires.

z

Admission attempts are made based on Queuing priority: Pqueue = Tmax – Telapsed

Tmax is the maximum time in the queue, default value is 5s

Telapsed is the time has queued


After the cell resource decision fails, the RNC performs queuing if the RNC receives an RAB ASSIGNMENT REQUEST message indicating the queuing function is supported The queuing algorithm checks whether the queue is full, that is, whether the number of service requests in the queue exceeds the queue length that is defined by the Queue length The queuing algorithm is triggered by the heartbeat timer, which is set through the Poll timer length . If the queue is not full: • Stamps this request with the current time. • Puts this request into the queue. If the queue is full: • Checks whether there are requests whose integrate priorities are lower than that of the priority of the new request. If there is, delete the low priority request, put the new service in the queue. (Otherwise, the queuing algorithm rejects the new request directly.) • Stamps the new request with the current time and then puts it into the queue. After the heartbeat timer (Poll timer length) expires, the queuing algorithm proceeds as follows: • Selects the request with the highest integrate priority for an attempt of resource allocation . • If the attempt fails, the queuing algorithm proceeds as follows: • Puts the service request back into the queue with the time stamp unchanged for the next attempt. • Chooses the request with the greatest weight from the rest and makes another attempt until a request is accepted or all requests are rejected.

Key parameters z

z

Queue algorithm switch

Parameter ID: QUEUEALGOSWITCH


Queue length

Parameter ID: QUEUELEN



Queue algorithm switch Parameter ID: QUEUEALGOSWITCH Value range: ON, OFF Content: This parameter specifies whether to support the queuing function. The default value of this parameter is OFF Set this parameter through SET QUEUEPREEMPT Queue length Parameter ID: QUEUELEN Value range: 5 to 20 Content: This parameter defines the length of a queue. The default value of this parameter is 5 Set this parameter through SET QUEUEPREEMPT

Key parameters z

z

Poll timer length

Parameter ID: POLLTIMERLEN


Max queuing time length

Parameter ID: MAXQUEUETIMELEN



Poll timer length Parameter ID: POLLTIMERLEN Value range: 1 to 6000 , step: 10ms Content: This parameter defines the length of the heartbeat timer. Each time the timer expires, the RNC chooses the service that meets the requirement to make an admission attempt . The default value of this parameter is 50 (500ms) Set this parameter through SET QUEUEPREEMPT Max queuing time length Parameter ID: MAXQUEUETIMELEN Value range: 1 to 60s Content: This parameter defines the maximum time that the service request can be in the queue. The default value of this parameter is 5s Set this parameter through SET QUEUEPREEMPT



Load%

LCC (Load Congestion Control) 100%

Overload state: OLC will be

section A

THOLC

used 1

2

section B

THLDR

Basic congestion state: LDR will be used

section C

Normal state: Permit entry

Times Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.

LCC (Load Congestion Control) consist of LDR (Load Reshuffling) and OLC (Over Load Control). In basic congestion state, LDR will be used to optimize resource distribution, the main rules is not to affect the feeling of users as possible as we can. In overload state, OLC will be used to release overload state quickly, keep system stability and the service of high priority users.

Load Reshuffling z

Reasons

When the cell is in basic congestion state, new coming calls could be easily rejected by system

z

Purpose

Optimizing cell resource distribution

Decreasing load level, increasing admission successful rate


When the usage of cell resource exceeds the basic congestion triggering threshold, the cell enters the basic congestion state. In this case, LDR is required to reduce the cell load and increase the access success rate.

Load Reshuffling z

Triggering of LDR

Power resources

Code resource

Iub resources

NodeB Credit resource


For power resource, the RNC performs periodic measurement and checks whether the cells are congested. For code, Iub, and NodeB credit resources, event-triggered congestion applies, that is, the RNC checks whether the cells are congested when resource usage changes.

Load Reshuffling z

LDR Actions:

Inter-frequency load handover

Code reshuffling

BE service rate reduction

AMR rate reduction

Inter-RAT load handover in the CS domain

Inter-RAT load handover in the PS domain

Real time service Iu QoS renegotiation

MBMS power reduction


When the cell is in basic congestion state, the RNC takes one of the actions in each period until the congestion is resolved

Load Reshuffling Actions triggered by different resources

If the downlink power admission uses the equivalent user number algorithm, basic congestion can also be triggered by the equivalent number of users. In this situation, LDR actions do not involve AMR rate reduction or MBMS power reduction, as indicated by the symbol "*" in above table Congestion of different resource may trigger different actions. For example, Credit congestion do not trigger “Inter-Frequency Load Handover”, “AMR Rate Reduction”, and “Code Reshuffling” When congestion of all resources is triggered, the action to be taken is based on the resource priority configuration.

Key parameters z


z

Parameter ID: NBMLDCALGOSWITCH

UL_UU_LDR

DL_UU_LDR

CELL_CODE_LDR

NodeB LDC algorithm switch

Parameter ID: NodeBLdcAlgoSwitch

IUB_LDR

NODEB_CREDIT_LDR


Cell LDC algorithm switch Parameter ID: NBMLDCALGOSWITCH Value range: ON, OFF Content: If ULLDR, DLLDR, CELL_CODE_LDR are selected, the corresponding algorithms are enabled. . Set this parameter through ADD CELLALGOSWITCH / MOD CELLALGOSWITCH NodeB LDC algorithm switch Parameter ID: NodeBLdcAlgoSwitch Value range: ON, OFF Content: If IUB_LDR, NODEB_CREDIT_LDR, are selected, the corresponding algorithms will be enabled; otherwise, disabled. . Set this parameter through ADD NODEBALGOPARA / MOD NODEBALGOPARA / SET LDCALGOPARA

Key parameters z

z

UL (RTWP) LDR trigger threshold

Parameter ID: ULLDRTRIGTHD


UL (RTWP) LDR release threshold

Parameter ID: ULLDRRELTHD



UL LDR trigger threshold Parameter ID: ULLDRTRIGTHD Value range: 0 to 100 , % Content: If the UL load of the cell is not lower than this threshold, the UL load reshuffling function of the cell is triggered. The default value of this parameter is 55% Set this parameter through ADD CELLLDM/MOD CELLLDM UL LDR release threshold Parameter ID: ULLDRRELTHD Value range: 0 to 100 , % Content: If the UL load of the cell is lower than this threshold, the UL load reshuffling function of the cell is stopped. The default value of this parameter is 45% Set this parameter through ADD CELLLDM / MOD CELLLDM

Key parameters z

z

DL (TX POWER) LDR trigger threshold

Parameter ID: DLLDRTRIGTHD


DL (TX POWER) LDR release threshold

Parameter ID: DLLDRRELTHD



DL LDR trigger threshold Parameter ID: DLLDRTRIGTHD Value range: 0 to 100 , % Content: If the DL load of the cell is not lower than this threshold, the DL load reshuffling function of the cell is triggered. The default value of this parameter is 70% Set this parameter through ADD CELLLDM / MOD CELLLDM DL LDR release threshold Parameter ID: DLLDRRELTHD Value range: 0 to 100 , % Content: If the DL load of the cell is lower than this threshold, the DL load reshuffling function of the cell is stopped. The default value of this parameter is 60% Set this parameter through ADD CELLLDM / MOD CELLLDM

Key parameters z

z

z

Cell LDR SF reserved threshold

Parameter ID: CELLLDRSFRESTHD


Ul LDR Credit SF reserved threshold

Parameter ID: ULLDRCREDITSFRESTHD


Dl LDR Credit SF reserved threshold

Parameter ID: DLLDRCREDITSFRESTHD



Cell LDR SF reserved threshold Parameter ID: CELLLDRSFRESTHD Value range: SF4, SF8, SF16, SF32, SF64, SF128, SF256 Content: If the SF corresponding to the current remaining code of the cell is higher than the threshold defined by this parameter, code congestion is triggered and the related handling actions are taken. The default value of this parameter is SF8 Set this parameter through ADD CELLLDR / MOD CELLLDR Ul LDR Credit SF reserved threshold Parameter ID: ULLDRCREDITSFRESTHD Value range: 0 to 100 , % Content: If the SF corresponding to the current UL remaining credit resource is higher than the threshold defined by this parameter, the UL credit LDR can be performed and the related handling actions are taken. The default value of this parameter is 60% Set this parameter through ADD NODEBLDR/MOD NODEBLDR Dl LDR Credit SF reserved threshold Parameter ID: DLLDRCREDITSFRESTHD Value range: 0 to 100 , % Content: If the value of SF corresponding to the current DL remaining credit resource is higher than the threshold defined by this parameter, the DL credit LDR can be performed and the related handling actions are taken. The default value of this parameter is SF8 Set this parameter through ADD NODEBLDR/MOD NODEBLDR

Key parameters z

The First / Second/ Third/ Fourth priority for load reshuffling

Parameter ID:

LdrFirstPri

LdrSecondPri

LdrThirdPri

LdrFourthPri

The default configuration is :

IUBLDR > CREDITLDR > CODELDR > UULDR


The First / Second/ Third/ Fourth priority for load reshuffling Parameter ID: LdrFirstPri / LdrSecondPri / LdrThirdPri / LdrFourthPri Value range: IUBLDR(Iub load reshuffling), CREDITLDR(Credit load reshuffling), CODELDR (Code load reshuffling), UULDR (Uu load reshuffling) Content: These parameters specify the triggering resource order when congestion of all resources are triggered. The default configuration is IUBLDR > CREDITLDR > CODELDR > UULDR Set this parameter through SET LDCALGOPARA

LDR procedure Turn on LDR algorithm switch

Mark "current LDR state = uncongested" Start LDM congestion indication report

Mark "current action

= first LDR action"

Clear "selected" mark of all UE LDR actions Congestion state indication

Wait for congestion indication

Current LDR state = congested?

Inter-freq load handover

Succeed?

N

Y

N Code reshuffling

Succeed?

Y

N BE rate reduction

Succeed?

Y

N Sequence of actions can be configured (current action is taken firstly)

Inter-system handover in CS domain Inter-system handover in PS domain

Succeed?

Y

N Succeed?

Y

Mark "current action = successful action"

N

AMR rate reduction

Succeed?

Y

N QoS renogiation on Iu interface

Succeed?

Y

N Y

MBMS power reduction

Succeed? N

No related action can be found Mark "current action

= first LDR action"

Wait time for LDR action duration

Key parameters z

z

LDR period timer length

Parameter ID: LDRPERIODTIMERLE


Gold User Load Control Switch

Parameter ID: GoldUserLoadControlSwitch



LDR period timer length Parameter ID: LDRPERIODTIMERLE Value range: 0 to 86400 s Content: This parameter specifies the period of load reshuffling . The default value of this parameter is 10 s Set this parameter through SET LDCPERIOD Gold User Load Control Switch Parameter ID: GoldUserLoadControlSwitch Value range: ON, OFF Content: This parameter specifies whether LDR actions are applicable to users of gold priority. The default value of this parameter is OFF Set this parameter through ADD CELLLDR / MOD CELLLDR

Key parameters z

DL LDR first / second / third / fourth / fifth / sixth / seventh / eighth / ninth / tenth action

Parameter ID:

DlLdrFirstAction / DlLdrSecondAction / DlLdrThirdAction / DlLdrFourthAction / DlLdrFifthAction / DlLdrSixthAction / DlLdrSeventhAction / DlLdrEighthAction / DlLdrNinthAction / DlLdrTenthAction

The default configuration is :

1st:CODEADJ , 2nd: INTERFREQLDHO , 3rd: BERATERED


DL LDR first / second / third / fourth / fifth / sixth / seventh / eighth / ninth / tenth action Parameter ID: DlLdrFirstAction / DlLdrSecondAction / DlLdrThirdAction / DlLdrFourthAction / DlLdrFifthAction / DlLdrSixthAction / DlLdrSeventhAction / DlLdrEighthAction / DlLdrNinthAction / DlLdrTenthAction Value range: NOACT (NO ACTION), INTERFREQLDHO (INTER-FREQ LOAD HANDOVER), BERATERED (BE TRAFF RATE REDUCTION), QOSRENEGO (UNCONTROLLED REAL-TIME TRAFF QOS RE-NEGOTIATION), CSINTERRATSHOULDBELDHO (CS DOMAIN INTER-RAT SHOULD BE LOAD HANDOVER), PSINTERRATSHOULDBELDHO (PS DOMAIN INTER-RAT SHOULD BE LOAD HANDOVER), AMRRATERED (AMR TRAFF RATE REDUCTION), MBMSDECPOWER(MBMS DESCEND POWER), CODEADJ(CODE ADJUST), CSINTERRATSHOULDNOTLDHO (CS DOMAIN INTER-RAT SHOULD NOT BE LOAD HANDOVER), PSINTERRATSHOULDNOTLDHO (PS DOMAIN INTER-RAT SHOULD NOT BE LOAD HANDOVER). Content: These parameters specify the LDR action order. The default configuration is 1st:CODEADJ , 2nd: INTERFREQLDHO , 3rd: BERATERED , Set this parameter through ADD CELLLDR / MOD CELLLDR / ADD NODEBLDR / MOD NODEBLDR

LDR Actions z

Inter-frequency load handover

Target users

Based on user integrate priority Current bandwidth for DCH or “GBR bandwidth for HSPA” has to be less than the UL/DL Inter-freq cell load handover maximum bandwidth parameter

Target cells

Load difference between current load and the basic congestion trigger threshold of target cell is larger than “UL/DL Inter-freq cell load handover load space threshold”


It is implemented as follows: 1. The LDR check whether the existing cell has a target cell of inter-frequency blind handover. If there is no such a target cell, the action fails, and the LDR performs the next action. 2. The principles of selecting inter-freq handover target cell are different as a result of the different resources which trigger the basic congestion. 1. If the basic congestion is triggered by the power resource: The LDR checks whether the load difference between the current load and the basic congestion triggering threshold of each target cell for blink handover is larger than the UL/DL Inter-freq cell load handover load space threshold (both the uplink and downlink conditions must be fulfilled). The other resources (code resource, Iub bandwidth, and NodeB credit resource) in the target cell do not trigger basic congestion. If the difference is not larger than the threshold, the action fails, and the LDR takes the next action. If there are more than one cell meeting the requirements, the first one is selected as the blind handover target cell. 2. If the basic congestion is triggered by the code resource: Weather there are blind handover target cells meeting the requirements is decided by the following conditions: The minimum SF of the target cell is not greater than that of current cell. The difference of code occupy rate between current cell and the target cell is greater than InterFreq HO code used ratio space threshold. The state of target cell is normal. If there is no such cell, this action fails and the LDR performs the next action. If there are more than one cell meeting the requirements, the first cell is selected as the blind handover target cell. 3. If the LDR finds out a target cell that meets the specified blind handover conditions, the LDR selects one UE to make an inter-frequency blind handover, depending on the UE’s ARP and occupied bandwidth. For the selected UE other than a gold user, its UL/DL current bandwidth for DCH, GBR bandwidth for HSPA, shall be less than and have the least difference from the UL/DL Inter-freq cell load handover maximum bandwidth parameter (Both the uplink and downlink condition must be fulfilled). If the LDR cannot find such a UE, the action fails. The LDR performs the next action.

Key parameters z

z

z

UL/DL Inter-freq cell load handover load space threshold

Parameter ID: UL/DLINTERFREQHOCELLLOADSPACETHD


InterFreq HO code used ratio space threshold

Parameter ID: LdrCodeUsedSpaceThd


UL/DL Inter-freq cell load handover maximum bandwidth

Parameter ID: UL/DLINTERFREQHOBWTHD



UL/DL Inter-freq cell load handover load space threshold Parameter ID: UL/DLINTERFREQHOCELLLOADSPACETHD Value range: 0 to 11 % Content: The target cell can be a cell for inter-frequency blind handover only when the UL/DL load space is higher than the threshold. The UL/DL load space is the difference between the UL/DL basic congestion triggering threshold and the current UL/DL load of a target cell for blind handover. . The default value of this parameter is 20% Set this parameter through ADD CELLLDR / MOD CELLLDR InterFreq HO code used ratio space threshold Parameter ID: LdrCodeUsedSpaceThd Value range: 0% to 100% (0~1) ,step:1% Content: The target cell can be used for inter-frequency blind handover only when the DL Code used ratio space is higher than the threshold. The DL Code used ratio space is the difference of code used ratio between the source cell and the target cell. The default value of this parameter is 13% Set this parameter through ADD CELLLDR / LST CELLLDR / MOD CELLLDR UL/DL Inter-freq cell load handover maximum bandwidth Parameter ID: UL/DLINTERFREQHOBWTHD Value range: 0 to 400000 bps Content: During the inter-frequency load handover, the UE is selected as the target of inter-frequency load handover from the UE set where the bandwidth is less than this threshold. The default value of this parameter is 200000 Set this parameter through ADD CELLLDR / MOD CELLLDR

LDR Actions z

BE Rate Reduction

Target RABs

Based on RAB integrate priority

The data rate of BE service is larger than GBR

Number of RABs to be selected is configurable


BE rate reduction is implemented by reconfiguring the bandwidth. Bandwidth reconfiguration requires signaling interaction on the Uu interface. The LDR algorithm is implemented as follows: 1. Based on the integrate priority, the LDR sorts the RABs into a descending order. The top RABs related to the BE services (whose current rate is higher than its GBR configured by SET USERGBR command) are selected. If the integrate priorities of some RABs are identical, the RAB with the highest rate is selected. The number of RABs to select is determined by the UL/DL LDR-BE rate reduction RAB number parameter. 2. The bandwidth of the selected services is reduced to the specified rate. 3. If services can be selected, the action is successful. If services cannot be selected, the action fails. The LDR takes the next action. 4. The reconfiguration is completed as indicated by the RB RECONFIGURATION message on the Uu interface and through the RL RECONFIGURATION message on the Iub interface. 5. The BE rate reduction algorithm is controlled by the DCCC algorithm switch. BE rate reduction can be performed only when the DCCC algorithm is enabled.

Key parameters z

UL /DL LDR-BE rate reduction RAB number

Parameter ID: UL/DLLDRBERATEREDUCTIONRABNUM



UL /DL LDR-BE rate reduction RAB number Parameter ID: UL/DLLDRBERATEREDUCTIONRABNUM Value range: 1 to 10 Content: These parameters specify the number of RABs to select in a UL/DL LDR BE rate reduction. If the number of RABs that fulfil the criteria for BE rate reduction is smaller than the value of this parameter, then all the RABs that fulfil the criteria are selected. The default value of this parameter is 1 Set this parameter through ADD CELLLDR / MOD CELLLDR

LDR Actions z

Uncontrolled Real-time service QoS Renegotiation

Target RABs


Real-time services in the PS domain


The load is reduced by adjusting the rate of the real-time services through uncontrolled realtime OoS renegotiation. Upon receipt of the message, the CN sends the RAB ASSIGNMENT REQUEST message to the RNC for RAB parameter reconfiguration. Based on this function, the RNC can adjust the rate of real-time services to reduce the load. The LDR algorithm is implemented as follows: 1. Based on the integrate priority, the LDR sorts the real-time services in the PS domain in descending order. The top services are selected for QoS renegotiation. 2. The LDR performs QoS renegotiation for the selected services. The GBR during service setup is the rate of the service after QoS renegotiation. 3. The RNC initiates the RAB Modification Request message to the CN for QoS renegotiation. 4. If the RNC cannot find a proper service for QoS renegotiation, the action fails. The LDR performs the next action.

Key parameters z

UL / DL LDR un-ctrl RT Qos re-nego RAB num

Parameter ID: UL/DLLDRPSRTQOSRENEGRABNUM



UL / DL LDR un-ctrl RT Qos re-nego RAB num Parameter ID: UL/DLLDRPSRTQOSRENEGRABNUM Value range: 1 to 10 Content: These parameters specify the number of RABs to select in a UL/DL LDR uncontrolled real-time QoS renegotiation. If the number of RABs that fulfil the criteria for uncontrolled real-time QoS renegotiation is smaller than the value of this parameter, then all the RABs that fulfil the criteria are selected. The default value of this parameter is 1 Set this parameter through ADD CELLLDR / MOD CELLLDR

LDR Actions z

Inter-system Handover In the CS/PS Domain

Target user

Based on the user integrate priority

Handover Indicator – “Handover to GSM should be performed” – "handover to GSM should not be performed"

GSM cell WCDMA cell Copyright © 2009 Huawei Technologies Co., Ltd. All rights reserved.

The 2G and 3G systems have different cell sizes and coverage modes. Therefore, blind handover across systems is not taken into account. The LDR is implemented in the downlink (e.g.) as follows: 1. Based on the integrate priority, the LDR sorts the UEs in descending order. The top CS/PS services are selected. 2. For the selected UEs, the LDR sends the load handover command to the inter-system handover module to ask the UEs to hand over to the 2G system. 3. The handover module decides to trigger inter-system handover, depending on the capability of the UE and the capability of the algorithm switch to support the compression mode. 4. This action is successful if any load handover UE is found. Otherwise, this action fails.

Key parameters z

z

UL / DL CS should be ho user number

Parameter ID: UL/DLCSINTERRATSHOULDBEHOUENUM


UL / DL CS should not be ho user number

Parameter ID: UL/DLCSINTERRATSHOULDNOTBEHOUENUM



UL / DL CS should be ho user number Parameter ID: UL/DLCSINTERRATSHOULDBEHOUENUM Value range: 1 to 10 Content: These parameters specify the number of users to select in a UL/DL Inter-RAT Should Be Load Handover in the CS Domain. If the number of users that fulfil the criteria for Inter-RAT Should Be Load Handover in the CS Domain is smaller than the value of this parameter, then all the users that fulfil the criteria are selected. The default value of this parameter is 3 Set this parameter through ADD CELLLDR / MOD CELLLDR UL / DL CS should not be ho user number Parameter ID: UL/DLCSINTERRATSHOULDNOTBEHOUENUM Value range: 1 to 10 Content: These parameters specify the number of users to select in a UL/DL Inter-RAT Should Not Be Load Handover in the CS Domain. If the number of users that fulfil the criteria for Inter-RAT Should Not Be Load Handover in the CS Domain is smaller than the value of this parameter, then all the users that fulfil the criteria are selected. The default value of this parameter is 3 Set this parameter through ADD CELLLDR / MOD CELLLDR

Key parameters z

z

UL / DL PS should be ho user number

Parameter ID: UL/DLPSINTERRATSHOULDBEHOUENUM


UL / DL PS should not be ho user number

Parameter ID: UL/DLPSINTERRATSHOULDNOTBEHOUENUM



UL / DL PS should be ho user number Parameter ID: UL/DLPSINTERRATSHOULDBEHOUENUM Value range: 1 to 10 Content: These parameters specify the number of users to select in a UL/DL Inter-RAT Should Be Load Handover in the PS Domain. If the number of users that fulfil the criteria for Inter-RAT Should Be Load Handover in the PS Domain is smaller than the value of this parameter, then all the users that fulfil the criteria are selected. The default value of this parameter is 3 Set this parameter through ADD CELLLDR / MOD CELLLDR UL / DL PS should not be ho user number Parameter ID: UL/DLPSINTERRATSHOULDNOTBEHOUENUM Value range: 1 to 10 Content: These parameters specify the number of users to select in a UL/DL Inter-RAT Should Not Be Load Handover in the PS Domain. If the number of users that fulfil the criteria for Inter-RAT Should Not Be Load Handover in the PS Domain is smaller than the value of this parameter, then all the users that fulfil the criteria are selected. The default value of this parameter is 3 Set this parameter through ADD CELLLDR / MOD CELLLDR

LDR Actions z

AMR Rate Reduction

Target user

AMR services and with the bit rate higher than the GBR



In the WCDMA system, voice services work in eight AMR modes. Each mode has its own rate. Therefore, mode control is functionally equal to rate control. The LDR algorithm is implemented as follows: 1. Based on the integrate priority, the LDR sorts the RABs in the descending order. The top UEs accessing the AMR services (conversational) and with the bit rate higher than the GBR are selected. 2. In uplink, the RNC sends the “Rate Control request” message through the Iu-UP to the CN to adjust the AMR rate to the GBR. 3. In downlink, The RNC sends the TFC CONTROL command to the UE to adjust the AMR rate to the assured rate. 4. If the RNC cannot find a proper service for AMR rate reduction, the action fails. The LDR performs the next action.

Key parameters z

UL/DL LDR-AMR rate reduction RAB number

Parameter ID: UL/DLLDRAMRRATEREDUCTIONRABNUM



UL/DL LDR-AMR rate reduction RAB number Parameter ID: UL/DLLDRAMRRATEREDUCTIONRABNUM Value range: 1 to 10 Content: These parameters specify the number of RABs to select in a UL/DL LDR AMR rate reduction. If the number of RABs that fulfil the criteria for AMR rate reduction is smaller than the value of this parameter, then all the RABs that fulfil the criteria are selected. The default value of this parameter is 3 Set this parameter through ADD CELLLDR / MOD CELLLDR

LDR Actions Code Reshuffling

z

Reallocate code resources for candidate user

Code Adjustment


The algorithm operates as follows: 1,Initialize the SF_Cur of the root node of subtrees to Cell LDR SF reserved threshold. 2,Traverse all the subtrees with this SF_Cur at the root node. Leaving the subtrees occupied by common channels and HSDPA channels out of account, take the subtrees in which the number of users is not larger than the value of the Max user number of code adjust parameter as candidates for code reshuffling. 3,Select a subtree from the candidates according to the setting of the LDR code priority indicator parameter. z

z

If this parameter is set to TRUE, select the subtree with the largest code number from the candidates. If this parameter is set to FALSE, select the subtree with the smallest number of users from the candidates. In the case that multiple subtrees have the same number of users, select the subtree with the largest code number.

4,Treat each user in the subtree as a new user and allocate code resources to each user. 5,Initiate the reconfiguration procedure for each user in the subtree and reconfigure the channel codes of the users to the newly allocated code resources. The reconfiguration procedure on the air interface is implemented through the PHYSICAL CHANNEL RECONFIGURATION message and that on the Iub interface through the RL RECONFIGURATION message.

Key parameters z

z

Max user number of code adjust

Parameter ID: MAXUSERNUMCODEADJ


LDR code priority indicator

Parameter ID: LdrCodePriUseInd

The default value of this parameter is TRUE


Max user number of code adjust Parameter ID: MAXUSERNUMCODEADJ Value range: 1 to 3 Content: This parameter specifies the maximum number of users that can be selected whenever code reshuffling is performed. The default value of this parameter is 1 Set this parameter through ADD CELLLDR / MOD CELLLDR LDR code priority indicator Parameter ID: LdrCodePriUseInd Value range: True, False Content: This parameter specifies whether to select preferentially the subtree with a relatively large code number during subtree selection. Set this parameter through ADD CELLLDR / MOD CELLLDR

LDR Actions z

MBMS Power Reduction

Purpose

The downlink power load can be reduced by lowering power on MBMS traffic channels


The LDR algorithm is implemented as follows: 1. Select all RABs with low priorities. 2. The RNC initiates the reconfiguration procedure and resets the transmit power of MTCH (FACH) to the minimum value. The transmit power corresponds to the MBMS service. 3. The reconfiguration procedure on the Iub interface is implemented through the COMMON TRANSPORT CHANNEL RECONFIGURATION REQUEST message.



Over Load Control z

Reasons

z

In overload state, system is not stable

Purpose

Ensuring the system stability and making the system back to the normal state as soon as possible

z

Triggering of Over Load

Power resource


After the UE access is granted, the power consumed by a single link is adjusted by the single link power control algorithm. The power varies with the mobility of the UE and the changes in the environment and the source rate. In some situations, the total power load of the cell may be higher than the target load. To ensure system stability, overload congestion must be handled.

Over Load Control z

Over Load triggering


If the current UL/DL load of an R99 cell is not lower than the UL/DL OLC Trigger threshold for some hysteresis (defined by the DL State Trans Hysteresis threshold in DL; not configurable in UL), the cell works in overload congestion state and the related overload handling action is taken. If the current UL/DL load of the R99 cell is lower than the UL/DL OLC Release threshold for some hysteresis (defined by the DL State Trans Hysteresis threshold in DL; not configurable in UL), the cell comes back to the normal state. The HSPA cell has the same uplink decision criterion as the R99 cell. The load in the downlink, however, is the sum of load of the non-HSPA power (transmitted carrier power of all codes not used for HS-PDSCH or HS-SCCH transmission) and the GBP..

Key parameters z


Parameter ID: NBMLDCALGOSWITCH

z

z

UL_UU_OLC, DL_UU_OLC

UL/DL OLC trigger threshold

Parameter ID: UL/DLOLCTRIGTHD


UL/DL OLC release threshold

Parameter ID: UL/DLOLCRELTHD



Cell LDC algorithm switch Parameter ID: NBMLDCALGOSWITCH Value range: OFF, ON Content: This parameter specifies the switch of UL/DL OLC. UL_UU_OLC: UL overload control algorithm DL_UU_OLC: DL overload control algorithm Set this parameter through ADD CELLALGOSWITCH / MOD CELLALGOSWITCH UL/DL OLC trigger threshold Parameter ID: UL/DLOLCTRIGTHD Value range: 0 to 100 % Content: If the UL load of the cell is not lower than the value of the UL OLC trigger threshold, the UL overload congestion control of the cell is activated. If the DL load of the cell is not lower than the value of the DL OLC trigger threshold, the DL overload congestion control of the cell is activated. Set this parameter through ADD CELLLDR / MOD CELLLDR UL/DL OLC release threshold Parameter ID: UL/DLOLCRELTHD Value range: 0 to 100 % Content: If the UL load of the cell is lower than the value of the UL OLC release threshold, the UL overload congestion control of the cell is deactivated. If the DL load of the cell is lower than the value of the DL OLC release threshold, the DL overload congestion control of the cell is deactivated. Set this parameter through ADD CELLLDR / MOD CELLLDR

The general OLC procedure covers the following actions: TF control of BE services, channel switching of BE services, and release of RABs. The RNC takes periodical actions if overload congestion is detected. When the cell is overloaded, the RNC takes one of the following actions in each period (defined by the OLC period timer length parameter, e.g.3s) until the congestion is resolved: 1. TF control of BE service (only for DCH BE service) 2. Switching BE services to common channel 3. Choosing and releasing the RABs (for HSPA or DCH service) If the first action fails or the first action is completed but the cell is still in congestion, then the second action is taken.

Key parameters z

OLC period timer length

Parameter ID: OLCPERIODTIMERLEN

The default value of this parameter is 3000 (ms)


OLC period timer length Parameter ID: OLCPERIODTIMERLEN Value range: 100 to 86400000 Content: This parameter specifies the period of overload control. The default value of this parameter is 3000 (ms) Set this parameter through SET LDCPERIOD

OLC Action z

TF Control

Target user


The RABs with the DCH BE services

Execution

The RNC sends the “TF control indication” message to the MAC.

MAC restricts the TFC selection : TFmax(N+1) = TFmax(N) x Ratelimitcoeff


Based on the RAB integrate priority, the OLC sorts the RABs into a descending order.The following RABs are selected: 1. The RABs with the DCH BE services 2. The RABs with the lowest integrate priority. 3. The number of RABs selected is DL/UL OLC fast TF restrict RAB number. The RNC sends the TF control indication message to the MAC. Each MAC of selected RABs will receive one TF control indication message and will restrict the TFC selection of the BE services to reduce the data rate step by step. MAC restricts the TFC selection in a way like that the maximum TB number is calculated with the formula: TFmax(N+1) = TFmax(N) x Ratelimitcoeff Ratelimitcoeff is a configurable parameter (DL OLC fast TF restrict data rate restrict coefficient). If the RNC cannot find an appropriate service for the TF control or the time for performing the TF control exceed the DL OLC fast TF restrict times parameter, the action fails. The OLC performs the next action. If the congestion is released, the RNC sends the congestion release indication to the MAC. At the same time, the rate recovery timer (whose length is defined by DL OLC fast TF restrict data rate recover timer length) is started. When this timer is expired, the MAC increases the data rate step by step. MAC recovers the TFC selection by calculating the maximum TB number with the formula: TFmax(N+1) = TFmax(N) x RateRecoverCoeff RateRecoverCoeff is a configurable parameter (DL TF rate recover coefficient)

OLC Action z

TF Control example


Before point A, the cell is not in OLC state. The downlink data transfer rate is 384 kbit/s, the corresponding TF is 12 x 336, and TFS is {12 x 336, 8 x 336, 4 x 336, 2 x 336, 1 x 336, 0 x 336}.336 is the TB size, 320 payload + 16 MAC head At point A, the cell enters OLC state. The RNC selects this RAB to do fast TF restriction. MAC restricts the TFC selection during time between point A and point B by calculating the maximum TB number as follows: TFmax(1) = TFmax(0) x Ratelimitcoeff = 12 x 0.68 = 8.16 Match 8.16 and the TFS. Therefore, the maximum TB number is 8. At point B, MAC performs further TFC restriction by calculating maximum TB number as follows: TFmax(2) = TFmax(1) x Ratelimitcoeff = 8 x 0.68 = 5.44 Match 5.44 and the TFS. Then, the maximum TB number is 4. At point C and point D, similar process is followed.

Key parameters z

z

UL/DL OLC fast TF restrict RAB number

Parameter ID: UL/DLOLCFTFRSTRCTRABNUM


UL/DL OLC fast TF restrict times

Parameter ID: UL/DLOLCFTFRSTRCTTIMES



UL/DL OLC fast TF restrict RAB number Parameter ID: UL/DLOLCFTFRSTRCTRABNUM Value range: 0 to 10 Content: These parameters specify the maximum number of RABs selected in a fast TF restriction of UL/DL OLC. If the number of RABs that fulfil the criteria for TF control is smaller than the value of this parameter, then all the RABs that fulfil the criteria are selected. The default value of this parameter is 3 Set this parameter through ADD CELLOLC / MOD CELLOLC UL/DL OLC fast TF restrict times Parameter ID: UL/DLOLCFTFRSTRCTTIMES Value range: 0 to 100 Content: These parameters specify the times of UL/DL OLC fast TF restrictions that are executed. The default value of this parameter is 3 Set this parameter through ADD CELLOLC / MOD CELLOLC

Key parameters z

z

DL TF rate restrict coefficient

Parameter ID: RateRstrctCoef


DL TF rate restrict timer length

Parameter ID: RateRstrctTimerLen



DL TF rate restrict coefficient Parameter ID: RateRstrctCoef Value range: 1 to 99 % Content: This parameter specifies the data rate restriction coefficient in the fast TF restriction. The smaller the parameter is, the more effective the TF restriction is. After receiving the TF control indication, the MAC obtains the maximum TF format with the formula TFmax' = TFmax x Ratelimitcoeff . The default value of this parameter is 68 % Set this parameter through ADD CELLOLC / MOD CELLOLC DL TF rate restrict timer length Parameter ID: RateRstrctTimerLen Value range: 1 to 65535 ms Content: This parameter specifies the length of the data rate restriction timer in the fast TF restriction. The smaller the value of this parameter is, the more effective the TF restriction is. The default value of this parameter is 3000 ms Set this parameter through ADD CELLOLC / MOD CELLOLC

Key parameters z

z

DL TF rate recover timer length

Parameter ID: RateRecoverTimerLen


DL TF rate recover coefficient

Parameter ID: RecoverCoef

The default value of this parameter is 130 %


DL TF rate recover timer length Parameter ID: RateRecoverTimerLen Value range: 1 to 65535 ms Content: This parameter specifies the length of the data rate recovery timer. The smaller the value of this parameter is, the faster the BE traffic rate increases after the congestion is resolved. The default value of this parameter is 5000 ms Set this parameter through ADD CELLOLC / MOD CELLOLC DL TF rate recover coefficient Parameter ID: RecoverCoef Value range: 100 to 200 % Content: This parameter specifies the data rate recovery coefficient in the fast TF restriction. The larger the parameter is, the larger the TF recover effect. After receiving congestion release indication, the MAC obtains the maximum TF format with the formula TFmax' = TFmax x RateRecovercoeff. The default value of this parameter is 130% Set this parameter through ADD CELLOLC / MOD CELLOLC

OLC Action z

Switching BE Services to Common Channel

Target user

Based on the user integrate priority

The users with the DCH or HSDPA BE services in PS

Execution

The RNC sends “RB Reconfiguration” message to UE

UE make a response by “RB Reconfiguration Complete”


The OLC algorithm for switching BE services to common channel operates as follows: Based on the user integrate priority, the OLC sorts all UEs that only have PS services including HSPA and DCH services (except UEs having also a streaming bearer) into a descending order. The top N UEs are selected. The number of selected UEs is equal to Transfer Common Channel user number. If UEs cannot be selected, the action fails. The OLC performs the next action. The selected UEs are switched to common channel.

Key parameters z

Transfer Common Channel User number

Parameter ID: TransCchUserNum



Transfer Common Channel User number Parameter ID: TransCchUserNum Value range: 1 to 10 Content: This parameter specifies the transfer common channel user number The default value of this parameter is 1 Set this parameter through ADD CELLOLC / LST CELLOLC / MOD CELLOLC

OLC Action z

Release of Some RABs

Target user

Based on the RAB integrate priority

DCH services RAB

Execution

The RNC sends “IU Release Request” message to CN

The RNC sends “RRC Connection Release” message to UE


OLC Algorithm for the Release of Some RABs in the Uplink: The OLC algorithm for the release of some RABs in the uplink operates as follows: Based on the integrate priority, the OLC sorts all RABs including HSUPA and DCH services into a descending order. The top RABs selected. If the integrate priorities of some RABs are identical, the RAB with higher rate (current rate for DCH RAB and GBR for HSUPA RAB) in the uplink is selected. The number of selected RABs is equal to UL OLC traff release RAB number. The selected RABs are released directly. OLC Algorithm for the Release of Some RABs in the Downlink The OLC algorithm for the release of some RABs in the downlink operates as follows: Based on the integrate priority, the OLC sorts all RABs into a descending order. The top-priority RABs are selected. If the integrate priorities of some RABs are identical, the RAB with higher rate (current rate) The number of selected RABs is equal to DL OLC traff release RAB number. The selected RABs are directly released.

Key parameters z

UL/DL OLC traff release RAB number

Parameter ID: UL/DLOLCTRAFFRELRABNUM



UL/DL OLC traff release RAB number Parameter ID: UL/DLOLCTRAFFRELRABNUM Value range: 0 to 10 Content: Either parameter specifies the number of RABs released in a UL or DL OLC release action. If the number of RABs that fulfil the criteria for release is smaller than the value of this parameter, then all the RABs that fulfil the criteria are selected. The default value of this parameter is 0 Set this parameter through ADD CELLOLC / MOD CELLOLC

Summary Load Control Algorithms PUC (Potential User Control) LDB (Intra-Frequency Load Balancing) CAC (Call Admission Control) IAC (Intelligent Admission Control) LDR (Load Reshuffling) OLC (Overload Control)


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