3G Ericsson Radio Parameter TELKOMSEL
Prepared by Adithya Yudha
Contents Idle Mode Handover Power Control Capacity Management Channel Switching HSDPA
Idle Mode and Common Channel behavior
Cell Selection 3G part Criteria for Cell Selection Squel > 0 , Squal = Qqualmeas-qQualMin (only for WCDMA cells) and Srxlev > 0 , Srxlev = Qrxlevmeas-qRxLevMin - Pcompensation (for all cells) Pcompensation = max (maxTxPowerUl - P, 0)
Qqualmeas > qQualMin (-18dB) and Qrxlevmeas > qRxLevMin (-115dBm) - max (maxTxPowerUl (24dB) - P, 0)
qQualMin : indicates the minimum required quality value in the cell. It is sent in system information, in SIB3 for the serving cell, and in SIB11 for adjacent cells qRxLevMin : indicates the minimum required signal strength in the cell. It is sent in SIB3 for the serving cell and in SIB11 for adjacent cells maxTxPowerUl : indicates the maximum allowed transmission power when the UE accesses the system on RACH. It is broadcast in SIB3
Cell Selection 3G part Squal > 0
Qqualmeas (dB) (CPICH Ec/N0)
Squal >0 AND Srxlev > 0
qQualMin (–18) Squal = Qqualmeas – qQualMin
qRxLevMin (–115) suitabl e cell?
Qrxlevmeas (dBm) CPICH RSCP
Pcompensation Pcompensation = max(maxTxPowerUl – P, 0) (dB)
Srxlev = Qrxlevmeas - qRxLevMin – Pcompensation
Srxlev > 0
Cell Reselection 3G part First according to S criteria Squal > 0 (only WCDMA cells) Srxlev > 0 The cells are ranked according to the R criteria: R(serving) = Qmeas(s) + qHyst(s) R(neighbor) = Qmeas(n) - qOffset(s,n) qHyst1 : Based on CPICH RSCP qHyst(s) qHyst2 : Based on CPICH Ec/No qOffset1sn : Based on CPICH RSCP qOffset(s,n)
qOffset2sn : Based on CPICH Ec/No (1 ) qHyst(s) and qOffset(sn) based on CPICH RSCP only
qualMeasQuantity =x
(2 ) With this setting the UE first makes qHyst(s) and qOffset(sn) based on CPICH RSCP . If a GSM cell is highest ranked, no more ranking is done. If a WCDMA neighbor is highest ranked, a second ranking takes place, this time according to CPICH Ec/No, and excluding all GSM neighbors
Cell Reselection 3G part R CRITERIA : R(serving) = Qmeas(s) + qHyst(s) R(neighbor) = Qmeas(n) - qOffset(s,n) Note that parameter qOffset1sn works identically for WCDMA-GSM and WCDMA-WCDMA neighbor relations. But the values of GSM RSSI and WCDMA CPICH RSCP are not of the same nature and therefore not directly comparable. [CPICH RSCP] = [GSM RSSI] + 7 As an example a measured RSCP on a WCDMA CPICH of -100 dBm would be comparable to a GSM broadcast channel RSSI of -93 dBm. A parameter setting of a GSM neighbor to qOffset1sn = +7 will thus make the received signal strength in the WCDMA and the GSM cell comparable.
Cell Reselection 3G part MEASUREMENT ON INTRA AND INTER-RAT NEIGHBOR The decision about when intrafrequency measurements are performed is made using the sIntraSearch parameter in relation to Squal: • If the Squal > sIntraSearch, the UE does not need to perform intrafrequency measurements. • If the Squal <= sIntraSearch value, the UE performs intrafrequency measurements. • If the sIntraSearch = 0 , is not sent to the serving cell, the UE performs intrafrequency measurements.
The decision about when GSM measurements are performed is made using the sRatSearch parameter in relation to Squal and the sHcsRat parameter in relation to Srxlev: • If the Squal > sRatSearch and the Srxlev > sHcsRat, the UE does not need to perform measurements on GSM cells. • If the Squal <= sRatSearch value and/or the Srxlev <= sHcsRat value, the UE performs measurements on GSM cells.
Squal <= sRatSearch Qqualmeas-qQualMin <= sRatSearch Qqualmeas <= qQualMin (-18dB) + sRatSearch (4dB) Srxlev <= sHcsRat Qrxlevmeas-qRxLevMin – Pcompensation <= sHcsRat Qrxlevmeas <= qRxLevMin (-107dBm) + 0 + sHcsRat (3dB)
Cell Reselection 3G part Measurements on GSM Neighbors
available If : CPICH Ec/No – qQualMin < SRatSearch
Rs = Serving WCDMA cell calculation, with
qHyst1 = 4 dB qOffset1sn = 0 dB
qQualMin = -18 dB Rs = CPICH RSCP/GSM RSSI + Qhyst1 sRATsearch = 4 dB Rn= CPICH_RSCP(n) or RXLEV(n) - Qoffset1 qOffset1sn = 7 dB qRxlevMin = -107 dBm
hysteresis parameter Rn = Neighbour WCDMA or GSM cell calculation with offset parameter
Yes
Rn higher in GSM cell
No Qhyst2 = 4 dB qOffset2sn = 0 dB
Cell re-selection to GSM If a TDD or GSM cell is ranked as the best cell, then the UE must perform cell re-selection to that TDD or GSM cell. If a FDD cell is ranked as the best cell and cell_selection_and_reselection-quality_measure is set to CPICH RSCP, the UE shall perform cell re-selection to that FDD cell. If a FDD cell is ranked as the best cell and cell_selection_and_reselection-quality_measure is set to CPICH Ec/No, the UE shall perform a second ranking of the FDD cells according to the R criteria using the measurement quantity CPICH Ec/No calculating the R values of the FDD cells.
Second ranking only for WCDMA cells based on CPICH Ec/No Rs = CPICH Ec/No + Qhyst2 Rn= CPICH Ec/No -Qoffset2
Cell re-selection to WCDMA cell of highest R value
RSCP
First ranking of all the cells based on CPICH RSCP (WCDMA) and RSSI (GSM)
GSM cell measurements
RSSI
Cell Reselection 3G part
Cell Reselection 2G part Measurements on 3G Neighbors The parameters QSI and QSC define thresholds and also indicate whether these measurements shall be performed when the signal strength (SS) of the serving cell is below or above the threshold. QSI is used for idle and packet switched modes and broadcast on BCCH and PBCCH (if enabled), while QSC is used for active mode, sent on SACCH There are 4 different scenarios to choose from. Parameters QSI and QSC are set per GSM cell and define both the scenario and the necessary threshold, at the same time: • UTRAN neighboring cells are measured only when the signal strength of the GSM serving cell is above the threshold set by QSI and QSC • UTRAN neighbor cells are measured only when the signal strength of the GSM serving cell is below the threshold set by QSI and QSC . • UTRAN neighbor cells are always measured. • UTRAN neighbor cells are never measured. This can be used to turn off the cell reselection/handover to UMTS, per cell, even if COEXUMTS is ON for the BSC.
Value
0
1
…
6
7
8
9
10
…
14
15
dBm
-98
-94
…
-74
Always
-78
-74
-70
…
-54
Never
If RLA_C < -94 UE starts 3G measurements
UE always measures 3G cells
If RLA_C > -70 UE starts 3G measurements
UE never measures 3G cells
Cell Reselection 2G part Example 1: If an UTRAN cell should serve purely to extend the coverage for MultiRAT MSs in GSM, it is logical to set QSI /QSC values from 0-6, since it's only needed to make cell reselection and handovers to UMTS when the GSM coverage falls low.
Cell Reselection 2G part Example 2: If an UTRAN cell is co-sited with a GSM cell, there is a certain correlation between signal strengths of the two systems. If the GSM is for example using 900MHz band it is very probable that the GSM signal strength will always be higher than the UTRAN signal, for a number of dBs. Therefore, there is no point in measuring UTRAN cells in low GSM signal conditions and values 8-14 can be selected accordingly.
Cell Reselection 2G part Criteria : CPICH Ec/No > FDDQMIN (-13dB) and CPICH RSCP > RLA(s+n) + FDDQOFF (-infinite) FDDQMIN Value
0
1
2
3
4
5
6
7
dBm
-20
-19
-18
-17
-16
-15
-14
-13
FDDQOFF Value
0
1
2
3
…
8
…
14
15
dBm
-32 (infinity)
-28
-24
-20
…
0
…
24
28
Always select irrespective of RSCP value
Reselect in case RSCP > GSM RXLev (RLA_C) +28dB
Cell Reselection 2G part Cell Reselection List BCCH: FDDQMIN, FDDQOFF
QSI = 7(always) Check levels every 5s from serving GSM cell and best 6 GSM neighbour cells
UE starts WCDMA measurements if Rxlev running average (RLA_C) is below or above certain threshold: RLA_C QSI or QSC
DEFAULT: fdd cell reselect offset: select always (value is -infinity) minimum fdd threshold = -12 dB
Compare levels of all GSM cells to WCDMA neighbour
Check quality of neighbour WCDMA cells, no priorities between WCDMA neighbours
UE can select WCDMA cell if the level of the serving GSM and non-serving GSM cells has been exceeded by certain offset for a period of 5 s: CPICH RSCP > RLA_C + FDDQOFF RSCP > (aveRxLev) + -32
FDDQMIN = -13 dB UE will re-select WCDMA cell in case it's quality is acceptable: CPICH Ec/No FDDQMIN EcNo -13
05.08:This may take up to 30s
FDDQOFF = -32 dB
WCDMA cell reselectio n
Idle Mode Parameter Summary Cell Selection and Reselection
accessClassNBarred
bandIndicator
Indicates whether or not access class N is barred ( N = 0 to 15). 0 : not barred 1 : barred Start from least significatant bit: bit 0 : class 0 bit 1 : class 1 bit 2 : class 2 ....... bit 15 : class 15 Indicates the frequency band of the external GSM cell. The BCCH frequency is unique for all GSM bands except the two GSM bands DCS1800 and PCS1900, so the band indicator is needed to discriminate between the two. When the ExternalGsmCell has a BCCH frequency indicating some other frequency band, then the band indicator is not needed and may be set to "Not applicable".
bcchFrequency cellReserved fachMeasOccaCycLenCoeff
BCCH frequency code in the GSM cell. Contains the absolute radio frequency channel number of the BCCH channel for the GSM cell. It uniquely identifies the BCCH. Indicates if this cell shall be reserved for operator use. If it is reserved, there will be no service to the UEs. Fach Measurement Occasion Cycle Length coefficient. A factor used when the UE performs inter-frequency and inter-system measurements. The UE uses this parameter to calculate the interval length in order to determine the repeating cycle of the measurement. 0 : not broadcasted in SIB 11. 1 : not used. 2 : not used. 3 : used when inter frequency and GSM neighbours. 4 : used when inter freqency or GSM neighbours. 5 - 12 not used.
interFreqFddMeasIndicator
Inter-frequency FDD measurement indicator. FALSE = No TRUE = Yes
Idle Mode Parameter Summary maxTxPowerUl The maximum UE transmission power on the RACH when accessing the system. Used in UE functions for cell selection/reselection in idle mode and connected mode. Also used by UTRAN to control the maximum TX power level an UE may use. If the current UE uplink transmit power is above the indicated power value, the UE shall decrease the power to a level below the power value. Value launched by System information (SIB11) for each intrafrequency measurement object corresponding to adjacent cells of serving cell. Unit: 1 dBm Resolution: 1 -50: -50 dBm ... 33: 33 dBm 100 : Default value. The parameter is not sent in SIB11 and the UE will use the maximum output power for this GSM cell, according to its radio access capability.
maxTxPowerUl (serving cell, WCDMA neighbor within same RNC) maxTxPowerUl (WCDMA neighbor belonging to another RNC) maxTxPowerUl (GSM neighbor) mcc The MCC part of the PLMN identity used in the GSM radio network. The PLMN identity consists of two parts: 1. MobileCountryCode, MCC, 3 digits 2. MobileNetworkCode, MNC, 2 or 3 digits Example: If MCC=125 and MNC=46 then plmnId=12546.
mnc
The MNC part of the PLMN identity used in the radio network. The PLMN identity consists of two parts: 1. MobileCountryCode, MCC, 3 digits 2. MobileNetworkCode, MNC, 2 or 3 digits Example: If MCC=125 and MNC=46 then plmnId=12546.
nmo primaryScramblingCode
Network operation mode that indicates whether the Gs interface between the SGSN and MSC/VLR is installed. The primary downlink scrambling code to be used in the external cell.
Idle Mode Parameter Summary qHyst1
Cell reselection hysteresis used in UE functions in idle and connected mode. Value launched by System information (SIB3). Resolution: 2
qHyst2
The hysteresis value of the serving cell. Used to perform cell ranking for the serving cell. Resolution: 2
qOffset1sn
Signal stength offset between source and target cells. Used when the IE "cell_selection_and_reselection_quality_measure" in SIB 11/12 is set to "CPICH RSCP". This is configured through UtranCell::qualMeasQuantity. Unit: 1 dB Resolution: 1 -50 : -50dB -49 : -49dB -48 : -48dB ...... 50 : 50dB
qOffset1sn (WCDMA neighbor relation) qOffset1sn (GSM neighbor relation) qOffset2sn (WCDMA neighbor relation) qQualMin
Used in UE functions for cell selection/reselection in idle mode and connected mode. Minimum required (acceptable) quality level in the cell (dB). Used to set cell border between two cells. Unit: 1 dB Resolution: 1 -24 : -24dB ...... 0 : 0dB 100 : Indicates that the minimum quality level has not been specified by the operator. The parameter is then not present in SIB11 for this neighbour. The UE will use the serving cell value (UtranCell MO value) instead.
qQualMin (serving cell, WCDMA neighbor within same RNC) qQualMin (WCDMA neighbor belonging to another RNC)
Idle Mode Parameter Summary qRxLevMin
Used in UE functions for cell selection/reselection in idle mode and connected mode. Minimum required (acceptable) RX level in the cell. (dBm). Value launched by System information (SIB11) for each intrafrequency measurement object corresponding to adjacent cells of serving cell. Unit: 1 dBm Resolution: 2 -115 : -115dBm -113 : -113dBm -111 : -111dBm -109 : -109dBm ..... -25 : -25 dBm 100 : Indicates that the minimum Rx level has not been specified by the operator. The parameter is then not present in SIB11 for this neighbour. The UE will use the serving cell value (UtranCell MO value) instead.
qRxLevMin (serving cell, WCDMA neighbor belonging to same RNC) qRxLevMin (WCDMA neighbor belonging to another RNC) qRxLevMin (GSM neighbor) Used in UE functions for cell selection/reselection in idle and qualMeasQuantity connected mode. Cell selection and reselection quality measure. Value launched by System information (SIB3, SIB11 and SIB12).
sHcsRat
RAT specific threshold in the serving cell used in the inter-RAT measurement rules. This parameter is used by the UE to decide when to start GSM measurements for cell reselection, if the serving cell is indicated to belong to a Hiearachical Cell Structure (HCS) GSM measurements in idle mode and state CELL_FACH are started by the UE when RSCP <= qRxLevMin + sHscRat. If sHcsRat is set to a negative value, this will be interpreted as 0 by the UE (according to 3GPP TS 25.331). Unit: 1 dB Resolution: 2
Idle Mode Parameter Summary sInterSearch
The decision on when measurements on inter frequencies shall be performed. If a negative dB value is configured the UE interprets the negative value as 0 dB. Unit: 2 dB Resolution: 1 0 : not sent 1 : -32 dB 2 : -30 dB ... 27 : 20 dB
sIntraSearch
The decision on when measurements on intra frequencies shall be performed. If a negative dB value is configured, the UE interprets the negative value as 0 dB. Unit: 2 dB Resolution: 1 0 : not sent 1 : -32 dB 2 : -30 dB ... 27 : 20 dB
sRatSearch The decision on when measurements on GSM frequencies shall be performed is made using this parameter in relation with Squal. If S_qual > this parameter, UE need not perform measurements on GSM cells. If S_qual <= this paramter, UE shall perform measurment on GSM cells. If a negative value is configured the UE interprets the negative value as 0. Unit: 1dB Resolution: 2 -32 : -32dB -30 : -30dB ......
Idle Mode Parameter Summary treSelection
Control of cell selection/reselection. Time-to-trigger for cell reselection in seconds. Value launched by System information (SIB3).
uarfcnDl
Downlink Utra Absolute Radio Frequency Channel Number. Specifies the channel number for the central DL frequency. The mapping from channel number to physical frequency is described in 3GPP specification TS 25.104. Unit: Channel number Resolution: N/A
uarfcnUl
Uplink Utra Absolute Radio Frequency Channel Number. Specifies the channel number for the central UL frequency. The mapping from channel number to physical frequency is described in 3GPP specification TS 25.104. Unit: Channel number Resolution: N/A
Idle Mode Parameter Summary Location and Routing Area Updating
att
Indicates to the UE whether IMSI attach/detach is allowed. (Some IMSIs are not allowed in some LAs.) This helps to facilitate the avoidance of unnecessary paging attempts. The value is sent on the BCCH. FALSE: IMSI attach not allowed TRUE: IMSI attach allowed
lAC
The Location Area Code of the external GSM cell. Note: the values 0000 and FFFE are reserved for special cases where no valid LAI exists in the MS. Old name: lAC
rAC
Routing Area Code of a routing area. An RA is used by UTRAN to page mobiles on request from the PS CN. When the parameter is changed, UTRAN shall update system information and notity UEs. Old name: rAC
t3212
Periodic update timer for LA update. Unit: 0.1 hours (= 1 decihour = 6 minutes = 360 seconds) Resolution: 1 0 means infinite time, i.e. not
Idle Mode Parameter Summary Paging
cnDrxCycleLengthCs
Core Network DRX cycle length coefficient (k) for UEs in idle mode, circuit switched. The cycle length is calculated as the k'th potential of 2, where k = 6..9. For example, 6 corresponds to cycle length 640 ms, 7 corresponds to cycle length 1280 ms, etc.
cnDrxCycleLengthPs
Core Network DRX cycle length coefficient (k) for UEs in idle mode, packet switched. The cycle length is calculated as the k'th potential of 2, where k = 6..9. For example, 6 corresponds to cycle length 640 ms, 7 corresponds to cycle length 1280 ms, etc.
noOfMaxDrxCycles
Paging notification duration. To notify UEs in IDLE mode about a system information update, the RNC sends a paging message on the PCH at every page occasion of a number of maximum DRX cycles.
noOfPagingRecordTransm
Number of preconfigured subsequent transmissions of the same Paging Record.
System Information
noOfMibValueTagRetrans sib1PlmnScopeValueTag sib1RepPeriod sib3RepPeriod sib5RepPeriod sib7RepPeriod sib11RepPeriod sib12RepPeriod sib1StartPos sib3StartPos sib5StartPos sib7StartPos sib11StartPos sib12StartPos sib7ExpirationTimeFactor updateCellReattsNo
Number of MIB value tag retransmissions on the FACH. The area identity part of PLMN scope value tages for SIB1
SIB7 use expiration time as re-read mechanism. The expiration time is sib7RepPeriod times sib7ExpirationTimeFactor. Number of update reattempts when an update of system information parameters in a cell failed.
Idle Mode Behaviour
UE States
Idle mode No connection to radio network (No RRC connection established) This minimizes resource utilization in UE and the network
CELL_FACH mode User Equipment (UE) in Connected Mode (has an RRC Connection to radio network) UE uses the common transport channels RACH or FACH If the parameter interFreqFDDMeasIndicator = 1, the UE will evaluate cell reselection criteria on inter-frequency cells (0)
CELL_DCH mode User Equipment (UE) in Connected Mode (has an RRC Connection to radio network) UE uses dedicated channels for transmitting data and signalling
Power Control
Pilot Channel Power
primary CPICH power should be 8 to 10% (~ 1 Watt) of the nominal RBS power at the reference point (~10W, while MCPA is 20W) The pilot power is designed to be equal in all cells at the Reference Point. primaryCpichPower = 30 dBm TopOfRack = primaryCpichPower + dlAttenuation System will adjust the TopOfRack to meet the required value. Consistency check on MaximumTransmissionPowerDL (Calculated vs. setting value) The feeder loss parameters ulAttenuation & dlAttenuation and electrical delay parameters ulElectricalDelay & dlElectricalDelay must be entered properly in the system (actual VSWR). More CPICH – less capacity trade off
P-CPICH
dl/ulAttenuation dl/ElectDelay
TopOfRack MaxTxPowerDL
Common Control Channel Power
With increasing CPICH power – capacity directly decreasis, but common channels and power per each dedicated channel is calculated from CPICH At CPICH 30 dBm, the common channel will be configured as follow:
Parameter Name primaryCpichPower
MO Type UtranCell
pchPower
Pch
primarySchPower
Value
Cumm(dBm)
Peak Power(W)
Typical AF
Avg Power(W)
30
1
1
1
-0.4
29.6
0.91
0.20
0.18
UtranCell
-1.8
28.2
0.66
0.10
0.07
secondarySchPower
UtranCell
-3.5
26.5
0.45
0.10
0.04
maxFach1Power
Fach
1.8
31.8
1.51
0.10
0.15
maxFach2Power
Fach
1.5
31.5
1.41
0.30
0.42
bchPower
UtranCell
-3.1
26.9
0.49
0.90
0.44
aichPower
Rach
-6
24
0.25
0.10
0.03
pichPower
Pch
-7
23
0.20
1.00
0.20
38.38
6.89
MaximumTransmissionPowerDL is design to be equal with Nominal RBS Power
2.53
Common Channel on Downlink Cell Setup and Reconfiguration - Downlink is the power used for transmitting the PCPICH. is the power used for transmitting on the BCH, relative to the primaryCpichPower value. is the power used for transmitting on the Primary SCH, relative to the primaryCpichPower value. is the power used for transmitting on the Secondary SCH, relative to the primaryCpichPower value. Common Transport Channel Setup and Reconfiguration - Downlink aichPower is the power used for transmitting on AICH, relative to the primaryCpichPower value. maxFach1Power defines the maximum power used for transmitting the first FACH channel, relative to the primaryCpichPower value. The first FACH is used for logical channels BCCH, CCCH, and DCCH control signaling. maxFach2Power defines the Maximum power used for transmitting the second FACH channel, relative to the primaryCpichPower value. The second FACH is used for logical channel DTCH traffic signaling. pOffset1Fach is the offset between downlink DPDCH and DPCCH TFCI field on FACH. pOffset3Fach is the offset between downlink DPDCH and DPCCH pilot field on FACH. pchPower is the power used for transmitting on the PCH, relative to the primaryCpichPower value. pichPower is the power used for transmitting on the PICH, relative to the primaryCpichPower value.
primaryCpichPower bchPower primarySchPower secondarySchPower
Common Channel on Uplink Common Transport Channel Setup and Reconfiguration - Uplink is a constant value in dB used by the UE to calculate the initial power on the PRACH according to the Open Loop Power Control procedure. powerOffsetP0 is the Power ramp step for the preamble when no acquisition indicator is received. powerOffsetPpm is the Power offset between the last transmitted preamble and the control part of the random access message. preambleRetransMax is the maximum number of preambles sent in one RACH preamble ramping cycle. maxPreambleCycle is the maximum number of preamble ramping cycle.
constantValueCprach
Common Channel on Uplink P_RACH The initial power on the PRACH - the power of the first preamble - is determined according to equation
P_PRACH = L_PCPICH + RTWP + constantValueCprach (-27dB)
L_PCPICH
: is the path loss estimated by the UE based on knowing the transmitted and received PCPICH power.
RTWP
: is the Received Total Wideband Power (uplink interference) level measured by the RBS.
constantValueCprach
: is used by the UE to calculate the initial power on the PRACH . This parameter is configurable and decides at which level below RTWP preamble ramping will start
Common Channel on Uplink POWER RAMP ON RACH To reach an appropriate received power level at the RBS, the UE uses preamble ramping. This procedure consists of the following steps: • The UE transmits a preamble. • As soon as the RBS properly detects the preamble, it sends an Acknowledgement Indicator (AI) on the AICH. • While not receiving any AI, the UE transmits a new preamble, increasing the transmission power with respect to the previous one by the configurable parameter powerOffsetP0.(3dB) • As soon as the UE receives an AI, it sends the PRACH message part. The power of the control part of the random access message is determined by the power of the last transmitted preamble and by a configurable offset powerOffsetPpm.(- 4dB) The power of the data part of the PRACH message is determined by the gain factors for PRACH, which is included in System Information.
Common Channel on Uplink POWER RAMP ON RACH
preambleRetransMax (8) parameter determines how many times PRACH preamble can be sent within one preamble ramping cycle (SIB5&6)
maxPreambleCycle (4) defines how many times the PRACH preamble ramping cycle procedure can be repeated before UE MAC reports a failure on RACH transmission to higher layers (SIB5&6)
Common Channel on Uplink
In average coverage conditions the RRC Connection Setup performance can be improved by tuning the open loop power control parameters These parameters are preambleRetransMax and & maxPreambleCycle powerOffsetPpm powerOffsetP0
L1 ACK / AICH Downlink Not detected BS MaxTXPowerUl powerOffsetP0 Initial preamble power
……
Uplink Preamble MS Preamble 1 2
…… Preamble
preambleRetransMax
# PRACH preambles transmitted during one PRACH cycle without receiving AICH response
maxPreambleCycle # preamble power ramping cycles that can be done before RACH transmission failure is reported
powerOffsetPpm
Message part
Handover
Soft/Softer Handover Inter-Frequency Handover Inter-RAT Handover Inter-RAT Cell Change HSDPA Mobility
Intra-Frequency Handover SOFTER HANDOVER MS simultaneously connected to multiple cells (handled by same BTS) No extra transmissions across Iub interface Mobile Evaluated HandOver (MEHO) Both UL and DL: Maximum Ratio Combining (MRC) is occurring in rake receiver SOFT HANDOVER MS simultaneously connected to multiple cells (from different BTSs) Extra transmission across Iub, more channel cards are needed Mobile Evaluated HandOver (MEHO) DL/UE: MRC UL/RNC: Frame selection combining HARD HANDOVER Arises when inter-RNC SHO is not possible (Iur not supported or Iur congestion) Decision procedure is the same as SHO (MEHO) Causes temporary disconnection
Inter-Frequency Handover Can be intra-BS, intra-RNC, inter-RNC Network Evaluated HandOver (NEHO) Inter-RAT (Inter-system) Handover Handovers between GSM and WCDMA (NEHO)
Entities Involved in Reporting, Evaluation, and Execution of Handover-Related Functions.
Entities Involved in Reporting, Evaluation, and Execution of Handover-Related Functions. The concept of event-triggered reporting as specified in 3GPP is used by handover evaluation and allows the UE to do some part of the evaluation. Thus, the UE is configured to evaluate and send measurement reports to the system only when certain events occur, that is, when a monitored cell is measured and the measurement result for a monitored cell fulfills certain criteria. When the conditions for triggering a certain handover are fulfilled, the handover evaluation part triggers the corresponding handover execution part.
3GPP-defined UE Associated Cell sets for Measurement
Active Set •The cells involved in soft handover and measured by the UE Virtual Active Set •The Active Set associated with a non-used frequency for support of Inter-Frequency evaluation Monitored Set •The cells only measured by the UE and not part of the Active Set. The monitored set can consist of intra-frequency, Inter-Frequency and Inter-RAT cells Detected Set •The intra frequency cells(P-CPICH scrambling codes) detected by the UE but not part of Active Set or monitored set
Soft/Softer Handover Event 1a, A primary CPICH enters the Reporting Range (measured P-CPICH Ec/No) > (P-CPICH Ec/No of the Best Cell in the Active Set) reportingRange1a + hysteresis1a /2 When a P-CPICH, not included in the Active Set, enters reportingRange1a + hysteresis1a/2, and the measured value remains in reportingRange1a + hysteresis1a/2 at least a time equal to timeToTrigger1a (Time to Trigger 1a), event 1a occurs. The UE sends a MEASUREMENT REPORT message for event 1a to the SRNC. If the report contains more than one cell fulfilling 1a criteria, only the one with highest Ec/No is considered and retained. If the retained cell is a valid cell and Active Set is not full (present cells in the Active Set is less than maxActiveSet parameter), the cell is proposed to be added to the Active Set. If the Active Set is full, the cell is proposed as a replacement of the worst cell in the Active Set provided that the reported cell has a better quality than the worst cell in the Active Set.
Event 1b, A primary CPICH leaves the Reporting Range (measured P-CPICH Ec/No) < (P-CPICH Ec/No of the best cell in the Active Set) reportingRange1b - hysteresis1b /2 When a P-CPICH, included in the Active Set, leaves reportingRange1b - hysteresis1b /2, and the measured value is outside reportingRange1b - hysteresis1b /2 during a time at least equal to timeToTrigger1b, event 1b occurs. The UE sends a MEASUREMENT REPORT message for event 1b to the SRNC. The handover algorithms will remove the reported cells one by one from the Active Set, however one cell is always kept in the Active Set for maintaining the connection.
Soft/Softer Handover Event 1a and Event 1b
10dB
6dB
320 ms
Cell (P_CPICH2) Would be proposed to be included in Active Set List
640 ms
Cell (P_CPICH2) Would be proposed to be excluded from Active Set List
Soft/Softer Handover Event 1c, A non-active primary CPICH becomes better than an Active Primary CPICH (measured P-CPICH Ec/No) > (P-CPICH Ec/No of the Best Cell in the Active Set) + hysteresis1a /2 When a P-CPICH, not included in the Active Set, becomes stronger than the weakest P-CPICH+hysteresis1c /2 in the Active Set during a time at least equal to timeToTrigger1c,and the Active Set is full (present cells in the Active Set is equal to maxActiveSet parameter) event 1c occurs. The UE sends a MEASUREMENT REPORT message for event 1c to the SRNC. If the retained cell is a valid cell, and the Active Set is full, the cell is proposed as a replacement for the weakest cell in the Active Set
Hysteresis1c (2dB)
Cell (P_CPICH4) Would be replaced P_CPICH3 in active set list
320 ms
Soft/Softer Handover Parameter Summary Setting Value
Remark
reportingRange1a
6
3 dB
reportingRange1b
10
5 dB
timeToTrigger1a
11
320ms
timeToTrigger1b
12
640ms
timeToTrigger1c
11
320ms
timeToTrigger1d
14
2560ms
hysteresis1a
0
0
hysteresis1b
0
0
hysteresis1c
2
1dB
hysteresis1d
15
7dB
maxActiveSet
3
3
Inter-RAT Handover Event 2d, The Estimated Quality of the Currently Used frequency is below a Certain Threshold When the estimated quality of the current WCDMA RAN used frequency is below the absolute threshold usedFreqThresh2dEcno - hysteresis2d/2, during a time at least equal to timeToTrigger2dEcno, OR the estimated quality of the current WCDMA RAN used frequency is below the absolute threshold usedFreqThresh2dRscp - hysteresis2d/2, during a time at least equal to timeToTrigger2dRscp, event 2d occurs.
Event 2f, The estimated quality of the currently used frequency is above a certain threshold When the estimated quality of the current WCDMA RAN used frequency is above the relative threshold usedFreqRelThresh2fEcno+usedFreqThresh2dEcno + hysteresis2f/2, during a time at least equal to timeToTrigger2fEcno, AND the estimated quality of the current WCDMA RAN used frequency is above the relative threshold usedFreqRelThresh2fRscp+usedFreqThresh2dRscp + hysteresis2f/2, during a time at least equal to timeToTrigger2fRscp event 2f occurs. The UE sends a MEASUREMENT REPORT message for event 2f to the SRNC. When SRNC receives the MEASUREMENT REPORT message for event 2f from the UE, measurements for IRATHO_eval event 3a or IFHO_eval event 2b and associated compressed mode usage is stopped.
Inter-RAT Handover Compressed Mode and de-Compressed Mode
UE stop compressed mode
1 + (-12 dB)
-12 dB
640 ms
UE start compressed mode to measure GSM or Interfreq Neighbors
2560 ms
Inter-RAT Handover Event 3a, The Estimated Quality of the Currently Used UTRAN Frequency is below a Certain Threshold and the Estimated Quality of the Other System is above a Certain Threshold The event 3a occurs according to the following points: • When the estimated quality of the WCDMA RAN used frequency is below the threshold usedFreqThresh2dEcno+utranRelThresh3aEcno - hysteresis3a/2 and the measured GSM carrier RSSI of a GSM/GPRS cell is above the absolute threshold gsmThresh3a, during a time at least equal to TimeToTrigger3a • when the estimated quality of the WCDMA RAN used frequency is below the threshold usedFreqThresh2dRscp+utranRelThresh3aRscp - hysteresis3a/2 and the measured GSM carrier RSSI of a GSM/GPRS cell is above the absolute threshold gsmThresh3a, during a time at least equal to TimeToTrigger3a • in case of the connection quality has been triggered in UL for UE TX power (event 6a, see Event 6a, The UE Tx Power becomes larger than an Absolute Threshold), the event 3a is triggered when the estimated quality of the WCDMA RAN used frequency is below the threshold usedFreqThresh2dRscp+utranRelThresh3aRscp+utranRelThreshRscp - hysteresis3a/2 and the measured GSM carrier RSSI of a GSM/GPRS cell is above the absolute threshold gsmThresh3a , during a time at least equal to TimeToTrigger3a.
Inter-RAT Handover
(-12 dB) + (-1dB)
RSSI -95dB
320 ms
IFHO & IRAT Parameter Summary
WCDMA to GPRS (PS) Gi
External Networks
GGSN Gn
Gn
3G-SGSN
2G-SGSN Gb
Iu
SRNC
BSC Abis
Iub
RBS RBS
RBS
RBS
RBS RBS
A successful IRATCC from WCDMA to GPRS SRNC
CN/SGSN
CELL_DCH 1. DCCH (AM) ”Measurement Report” (Event 2d) 2. Evaluation of MR 3. Compressed Mode Control 4. DCCH (AM) ”Measurement Control”
5. DCCH (AM) ”Measurement Report” (Event 3a) 6. Evaluation of MR 7. DCCH (AM):CELL_DCH Cell Change Order from UTRAN 8. GSM: RA Update 9. ”SRNS Context Request” 10. Stop DL Transmission 11. ”SRNS Context Response”
12. ”Iu Release Command” 13. Dedicated Radio Link Release 14. ”Iu Release Complete”
Target BSS
GSM to WCDMA (voice) : Measurements on WCDMA Cells Four different scenarios:
WCDMA RAN neighbor cells are measured only when the signal strength of the GSM serving cell is above the threshold set by QSI and QSC.
WCDMA RAN neighbor cells are measured only when the signal strength of the GSM serving cell is below the threshold set by QSI and QSC.
WCDMA RAN neighbor cells are always measured.
WCDMA RAN neighbor cells are never measured. This can be used to turn off the cell reselection/handover to WCDMA, per cell, even if COEXUMTS (parameter used to activate the functionality of making handovers and cell reselections between GSM and WCDMA) is on for the BSC.
Load sharing
Load sharing • Load sharing to 2nd carrier at RRC establishment Least loaded cell (Highest difference between power and pwradm) is chosen by sending RRC connection reject with redirection info to 2nd carrier.
• Directed Retry to GSM at RAB establishment When Dl power reaches ‘loadSharingGsmThreshold’ percentage of pwradm, calls are targeted to be offloaded to GSM. This is achieved by rejecting RAB establishment requests with ‘directed retry’ as a cause.
Load sharing capabilities available in the WCDMA RAN
Inter-Frequency Load Sharing
* Not operator configurable
Inter-Frequency Load Sharing At
call set-up - RRC Connection Establishment for all RABs
by Downlink Transmitted Carrier Power* (load on source > 50% and load on target less than source by a 10 % margin) The feature is activated in an RNC by setting the parameter loadSharingRrcEnabled to TRUE f2 f2 TRUE/FALSE The attribute loadSharingCandidate specifies whether the target cell is a load-sharing neighbor of the source cell Triggered
f1
f1
f1
f1
Inter-Frequency Load Sharing (RRC redirection) (Extra Slide) RNC Idle Mode ”RRC Connection Request” CCCH/RACH F1 ”RRC Connection Reject” CCCH/FACH Cell selection on designated UTRA carrier ”RRC Connection Request” CCCH/RACH
F2
”RRC Connection Setup” CCCH/FACH
Includes ‘Frequency Info’ IE
2nd will not be redirected but may be successful or rejected due to congestion
Directed retry to GSM Applicable for voice in P3 GSM
Admission Control
WCDMA
Directed retry to GSM
Directed retry to GSM At call set-up - RAB Establishment for voice Triggered by Downlink Transmitted Carrier Power
The feature is activated in an RNC by setting the parameter loadSharingDirRetryEnabled to TRUE
One GSM target can be defined for each WCDMA cell via the cell parameter directedRetryTarget
loadSharingGsmThreshold specifies the minimum load at which offloading to GSM begins: ex 80% of pwrAdm
loadSharingGsmFraction specifies the percentage of Directed Retry candidates to be diverted to GSM while the cell load is above the specified load threshold
Directed Retry to GSM UE
RBS/RNC
CN
RAB Assignment Request Directed Retry decision to send
RAB Assignment Response (failed, cause=directed retry) Relocation Required Contacts GSM cell and orders relocation
HO from UTRAN command
Relocation Command
Successful access to GSM
Iu release Command Iu release Complete
Voice calls can be relocated to GSM due to high load in WCDMA If the call is not accepted in GSM - try in WCDMA again!
Load balancing for voice between WCDMA-GSM
Features Introduction & Roadmap
When out of coverage, the WCDMA voice call is handed over to GSM
When GSM load reaches a customizable threshold, voice calls can be handed over to WCDMA
WCDMA coverage Dual Mode UE
GSM terminal
GSM coverage Load based handover to GSM during call set up, Directed Retry (P3) to GSM
Channel Switching
Channel Switching
Channel Switching Parameter Summary
Channel Switching
1. Common to Dedicated Evaluation Monitors if the UE shall be switched from a common to a dedicated transport channel due to large amount of user data buffered in the RNC or the UE.
2. Dedicated to Dedicated Up-Switch Evaluation Monitors if the throughput becomes close to the max user bandwidth and switch to the next higher bitrate radio bearer is required.
2a. Dedicated to Dedicated Coverage triggered Down-Switch Evaluation Monitors if a switch to a lower rate radio bearer is required due to coverage.
3. Dedicated to Common Evaluation Monitors if a switch from a Cell_DCH to Cell_FACH is required due to a decrease in transmitted user data.
4. Common to Idle Evaluation Monitors if a switch from Cell_FACH to Idle mode is required due to a complete lack of user data transmission.
Channel Switching
Multi-RAB Down-switch Evaluation Monitors if a release (or downswitch) of PS I/B RAB shall be initiated due to lack of PS data throughput (zero), resulting in a single speech 12.2 kbps (or speech + PS 0/0) or CS64 RAB.
Multi-RAB Up-switch Evaluation Monitors if an upswitch from multi-RAB SP0 to multi-RAB SP64 shall be initiated due to data buffered in either RNC or UE.
Channel Switching
Future releases stand-alone interactive RAB
speech + interactive RAB
HS
speech + 384/HS
384/HS
DCH
64/384 speech + 64/HS
128/128
64/HS
speech + 64/64
64/128
speech + 0/0
64/64
Low/No throughput Measurement for down Switch timer period FACH
Low/No RLC buffer load for Inactivity timer period
IDLE
PS RAB Establishment
UL throughputbased upswitch
activity/inactivity-based switching UL and/or DL
coverage-triggered downswitch (DL only)
DL throughputbased upswitch
choice based on UEand cell-capability
Capacity Management
Admission control workflow Resource request
* Current default values Yes, then block
Is admission blocked by Congestion Control?
No, then accept
Yes, then block
No
Check if the requested + estimated # compressed mode RL > compModeAdm
15*
75*
No Yes, then block
No
Check if the requested code usage + estimated code usage > dLCodeAdm
70*
Check if the requested ASE UL + estimated ASE UL > aseUlAdm
Only checked if No BE-service requests Check if the requested Check if the requested DL SF + estimated DL SF ASE DL + estimated DL ASE > > No sfXAdm * aseDlAdm
No
Yes, then SF8adm= 8* block SF16adm= 16* SF32adm= 32*
Yes, then block
Check if the requested DL Pwr + estimated Pwr > pwrAdm
•X = 8 or X = 32 •X = 16
240*
160* Yes, then block
Yes, then block
Soft Congestion mechanism New request for ng 64/128, ng 64/64 or g access
Admission Control blocks the new request
An existing ng user of 64/384 will be switched down to 64/128 or an existing ng user of 64/128 will be switched down to 64/64
Spreading Factor (SF) limits used in Admission Control
8*
* Current default values
16* 32*
ASE release order Core Network
Iu
Iu
SRNC & DRNC
SRNC Iur
over Iu:
over Iur:
1.
Non-guaranteed service class connections
2.
Non-guaranteed service class connections
3.
CS/streaming service class connections
4.
CS /streaming service class connections
5.
Speech users
6.
Speech users
HSDPA
HSDPA Parameter Summary Parameter Name
Default Value
HSPATHLOSSTHRESHOLD
170
170
10
10
2
2
-20
-20
CQIERRORSABSENT HSPOWERMARGIN HSSCCHMAXCODEPOWER QUEUESELECTALGORITHM SUPPORTOF16QAM
Initial Setting TELKOMSEL
ROUND_ROBIN FALSE
ROUND_ROBIN TRUE
MAXHSRATE
15
30
HSONLYBESTCELL
1
1
HSHYSTERESIS1D
10
10
HSQUALITYESTIMATE HSTIMETOTRIGGER1D
CPICH_RSCP 640
CPICH_RSCP 640
MAXHSRATE
The HSDPA Iub flow control algorithm adjusts the available bit rate over Iub based mainly on the maximum possible air interface bitrate received from the scheduler, the number of users in a cell and Iub congestion indications. The RBS uses the parameter maxHsRate to determine the maximum bit rate to be used for HS-DSCH data frame traffic in one aggregated bit pipe over Iub.
The parameter maxHsRate should be configured for each RBS to represent the maximum MAC-d PDU bitrate of HS-DSCH data frames, which is available for the AAL2 path or paths carrying HSDPA traffic to the RBS in question. The parameter may be set to a MAC-d PDU bit rate of 1.5 Mbps (the default value), when one dedicated physical E1 link is used for HSDPA traffic. This maximum bitrate level is the same as the bitrate expressed by the CAPACITY ALLOCATION control frames.
As an example, the default value of this parameter has been obtained by multiplying the HSDPA available ATM bandwidth (excluding IMA overhead), e.g. 1.92 Mbps, with a factor of 0.79. This factor is dependent on the average number of MAC-d PDUs per HS-DSCH data frame. In this case, it is based on having 10 MAC-d PDUs (336 bits) per HS-DSCH data frame in average. It should be noted that assuming a lower number of PDUs per data frame gives a lower factor and vice versa.
The parameter value of maxHsRate also depends on how the transport network is configured, e.g. if ATM VC Cross Connect is used or if AAL2 switching is used. It depends on how the ATM VCs etc are configured, e.g. for HS traffic only, sharing with AAL2 class A and B, several AAL2 paths for HS etc. Therefore it is recommended to follow the guidelines given by Ericsson regarding transport network dimensioning before setting a value for this parameter.
16QAM Modulation
The RBS hardware supports both QPSK and 16QAM modulation. However, support of 16QAM is an optional feature which can be configured on cell level using the parameter supportOf16qam. The available modulation type impacts the maximum achievable bit rate in the cell,
Maximum Achievable User Bit Rate at the RLC Level As a Function of the UE HS-DSCH Category and Modulation Type
