GSM BSS GBSS17.1
Fast LTE Reselection at 2G CS Call Release Feature Parameter Description Issue
Draft A
Date
2015-01-15
HUAWEI TECHNOLOGIES CO., LTD.
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Contents 1 About This Document 1.1 Scope 1.2 Intended Audience 1.3 Change History
2 Overview 2.1 Introduction 2.2 Benefits 2.3 Feature Support by NE
3 Technical Description 3.1 Overview 3.2 Signaling Process 3.2.1 Common CSFB Calls 3.2.2 Ultra Flash CSFB Calls 3.2.3 SRVCC Calls 3.3 Specifications
4 Related Features 4.1 Prerequisite Features 4.2 Mutually Exclusive Features 4.3 Impacted Features
5 Network Impact 5.1 System Capacity 5.2 Network Performance
6 Engineering Guidelines 6.1 When to Use Fast LTE Reselection at 2G CS Call Release 6.2 Required Information 6.3 Network Planning 6.4 Deploying Fast LTE Reselection at GSM CS Call Release 6.4.1 Deployment Requirements 6.4.2 Activation 6.4.3 Activation Observation 6.4.4 Deactivation 6.5 Performance Monitoring 6.6 Parameter Optimization 6.7 Troubleshooting
7 Parameters
8 Counters 9 Glossary 10 Reference Documents
1 About This Document 1.1 Scope This document describes GBFD-511312 Fast LTE Reselection at 2G CS Call Release, including its technical principles, related features, network impact, and engineering guidelines.
1.2 Intended Audience This document is intended for personnel who: Need to understand the feature described herein Work with Huawei products
1.3 Change History This section provides information about the changes in different document versions. There are two types of changes: Feature change Changes in features of a specific product version Editorial change Changes in wording or addition of information that was not described in the earlier version
Draft A (2015-01-15) Compared with Issue 02 (2014-05-31) of GBSS16.0, Draft A (2015-01-15) of GBSS17.1 includes the following changes. Change Type Feature change
Editorial change
2 Overview The Fast LTE Reselection at GSM CS Call Release feature is one of a number of interoperability features provided by Huawei to enable GSM and LTE networks to work together smoothly. NOTE:
All MSs involved in this feature are GSM/LTE dual-mode MSs. The FDD-based LTE is not distinguished from the TDD-based LTE in this document. FDD stands for frequency division duplex, and TDD stands for time division duplex.
2.1 Introduction When an MS terminates a call on a GSM network, the MS camps on the cell in which the call is released. When a neighboring LTE cell meets the requirements for cell reselection, the MS reselects to the LTE cell. Before initiating the cell reselection to the LTE cell, the MS must receive system information (SI) and calculate cell reselection parameters. This procedure takes an extended period of time. When the Fast LTE Reselection at GSM CS Call Release feature is enabled, the BSC sends the Channel Release message after an MS terminates a call in a GSM cell. The message carries the "cell selection indicator after release" information element (IE). Based on the IE, the MS reselects to the specified LTE cell without performing cell reselection calculations, thereby accelerating cell reselection.
2.2 Benefits The Fast LTE Reselection at GSM CS Call Release feature provides the following benefits: Improves user experience. This feature decreases the GSM-to-WCDMA cell reselection duration to 1–2s so that an MS can select an LTE cell immediately after it terminates a call in a GSM cell. Increases operators' revenues. This feature increases the duration in which an MS camps on an LTE cell and therefore increases the operators' revenues from the LTE network.
2.3 Feature Support by NE Table 2-1 Feature support by NE Feature Name Fast LTE Reselection at 2G CS Call Release NOTE: √ indicates that the NE supports this feature. × indicates that the NE does not support this feature.
3 Technical Description 3.1 Overview When the SPTRAPIDSEL(BSC6900,BSC6910) parameter is set to SUPPORT(Support), a fast reselection from the source GSM cell to the target LTE cell is allowed. When the Fast LTE Reselection at GSM CS Call Release feature is enabled, the BSC sends the Channel Release message after an MS terminates a call in a GSM cell. The message contains the frequency information about neighboring LTE cells. Based on the frequency information, the MS reselects to an appropriate neighboring LTE cell that works on that frequency. The Fast LTE Reselection at GSM CS Call Release feature (referred to as Fast Return) is typically applicable to the following calls: Circuit switched fallback (CSFB) calls
If the LTE network does not carry voice services using Voice over Internet Protocol (VoIP), an MS camping on the LTE network is migrated to a GSM cell using the CSFB procedure to perform voice services. Calls performed by such MSs are CSFB calls, including common CSFB calls and Ultra Flash CSFB calls. Single radio voice call continuity (SRVCC) calls If the LTE network carries voice services using VoIP, at the LTE coverage edge or in heavilyloaded LTE areas, VoIP calls are handed over to the CS domain of the GSM network using the SRVCC procedure. These calls are SRVCC calls.
3.2 Signaling Process 3.2.1 Common CSFB Calls When the DecodeCSFBInd(BSC6900,BSC6910) parameter is set to ON(On), the BSC implements Fast Return only for CSFB calls. Based on frequency selection modes, Fast Return for common CSFB calls is classified into measurement-based Fast Return and configuration-based Fast Return.
Measurement-based Fast Return When FASTRETURNMEASSPT(BSC6900,BSC6910) is set to ON(On) and an MS supports LTE frequency measurement, the BSC selects LTE frequencies for the MS based on the LTE frequency measurement result. Figure 3-1 shows the procedure for implementing measurement-based Fast Return. Figure 3-1 Procedure for implementing measurement-based Fast Return
1. After the traffic channel (TCH) is established, the BSC sends the Measurement Information message to the MS. This message includes measurement parameters and frequencies of neighboring LTE cells whose SPTRAPIDSEL(BSC6900,BSC6910) is set to SUPPORT(SUPPORT). 2. Upon receiving the Measurement information message, the MS measures all those neighboring LTE cells and selects neighboring LTE cells that meet the requirements according to the measurement parameters. The MS then sends the BSC a Measurement report message that carries the information about selected cells. The number of neighboring LTE cells to be reported is specified by EUTRANFREQCNUM(BSC6900,BSC6910). The following principles apply when an MS selects neighboring LTE cells:
The MS selects neighboring cells whose calculated reference signal received power (RSRP) values are greater than the value of FDDFASTRETURNRSRPTH(BSC6900,BSC6910) or TDDFASTRETURNRSRPTH(BSC6900,BSC6910) and sorts them in descending order.
The first n neighboring LTE cells will be reported to the BSC, where n is specified by EUTRANFREQCNUM(BSC6900,BSC6910). NOTE:
The calculated RSRP value is equal to the sum of the RSRP value measured by an MS and the offset value specified by FDDLTEOFFSET(BSC6900,BSC6910) or TDDLTEOFFSET(BSC6900,BSC6910). FDDFASTRETURNRSRPTH(BSC6900,BSC6910) and FDDLTEOFFSET(BSC6900,BSC6910) are parameters of neighboring LTE FDD cells. TDDFASTRETURNRSRPTH(BSC6900,BSC6910) and TDDLTEOFFSET(BSC6900,BSC6910) are parameters of neighboring LTE TDD cells. 3. When a call is complete, the MS sends a Disconnect message to the MSC over the fast associated control channel (FACCH). 4. The MSC sends a Clear Command message to the BSC, instructing the BSC to initiate the call release procedure.
When DecodeCSFBInd(BSC6900,BSC6910) is set to ON(On), the BSC determines whether the call is a CSFB call based on the the CSFB Indication information element (IE) in the Clear Command message. The BSC initiates the call release procedure only for CSFB calls. That is, Fast Return takes effect only for CSFB calls.
When DecodeCSFBInd(BSC6900,BSC6910) is set to OFF(Off), the BSC initiates the call release procedure regardless of whether the call is a CSFB call. That is, Fast Return takes effect for all GSM/LTE dual-mode terminals.
5. The BSC sends the MS a Channel Release message that contains frequencies of neighboring LTE cells. The MS then reselects an appropriate neighboring LTE cell working on the specified frequency. The frequencies contained in the Channel Release message vary depending on the following conditions:
When LTEFastReturnFrqSendOptSw(BSC6900,BSC6910) is set to ON(On), the BSC filters measurement reports (MRs) sent by the MS, and based on common priorities sends the MS the Channel Release message that contains LTE frequencies reported in multiple MRs.
When LTEFastReturnFrqSendOptSw(BSC6900,BSC6910) is set to OFF(Off), the BSC does not filter MRs sent by the MS and sends the MS the Channel Release message that contains the LTE frequency of the best cell.
Configuration-based Fast Return The BSC selects LTE frequencies based on configurations when either of the following conditions is met: CSFBFastReturnBaseCfgSw(BSC6900,BSC6910) and FASTRETURNMEASSPT(BSC6900,BSC6910) are set to ON(On). MSs do not support LTE frequency measurement. FASTRETURNMEASSPT(BSC6900,BSC6910) is set to OFF(Off). NOTE: Fast Return is not triggered if all of the following conditions are met: CSFBFastReturnBaseCfgSw(BSC6900,BSC6910) is set to OFF(Off).
FASTRETURNMEASSPT(BSC6900,BSC6910) is set to ON(On). MSs do not support LTE frequency measurement. The procedure for implementing configuration-based Fast Return is similar to that for implementing measurement-based Fast Return. The differences are as follows: The configuration-based Fast Return does not involve the Measurement Information and Measurement Report messages. During configuration-based Fast Return, the Channel Release message contains the frequencies of the neighboring LTE cells whose SPTRAPIDSEL(BSC6900,BSC6910) is set to SUPPORT(SUPPORT). The frequencies are configured when those LTE cells are added. If LTEFastReturnFrqSendOptSw(BSC6900,BSC6910) is set to ON(On), the BSC filters configured LTE frequencies based on MS capabilities before sending the frequencies to MSs. Otherwise, the BSC does not filter configured LTE frequencies before sending the frequencies to MSs.
3.2.2 Ultra Flash CSFB Calls Based on frequency selection modes, Fast Return for Ultra Flash CSFB calls is classified into measurement-based Fast Return and configuration-based Fast Return.
Measurement-based Fast Return When FASTRETURNMEASSPT(BSC6900,BSC6910) is set to ON(On) and an MS supports LTE frequency measurement, the BSC selects LTE frequencies for the MS based on the LTE frequency measurement result. Measurement-based Fast Return for Ultra Flash CSFB calls is similar to that for common CSFB calls. The differences lie in the following aspects: CSFB call identification method The BSC checks whether the configurations of MCC, MNC, LAC, and SAC in the service area identifier (SAI) for a call are consistent with those configured on the MSC server. If they are, the BSC determines that the call is an Ultra Flash CSFB call. MCC, MNC, LAC, and SAC are specified by UltraFlashCSFBSAIMCC(BSC6900,BSC6910), UltraFlashCSFBSAIMNC(BSC6900,BSC6910), UltraFlashCSFBSAILAC(BSC6900,BSC6910), and UltraFlashCSFBSAISAC(BSC6900,BSC6910), respectively. LTE frequencies contained in the Measurement Information message For Ultra Flash CSFB calls: When FreqFiltBaseIRATMeasCfgSw(BSC6900,BSC6910) is set to ON(On), the BSC includes the LTE frequencies that meet both of the following conditions in the MI for an MS: - The frequencies are configured as neighboring LTE cell frequencies. - The frequencies are contained in the IRAT Measurement Configuration IE of the Handover Request message. When FreqFiltBaseIRATMeasCfgSw(BSC6900,BSC6910) is set to OFF(Off), the BSC includes all the configured neighboring LTE cell frequencies in the MI. The BSC includes LTE frequencies and measurement information in the MI based on MS capabilities. If MSs do not support LTE frequency measurement or the BSC does not obtain MS capabilities, the BSC determines whether to trigger configuration-based Fast Return based on the value of CSFBFastReturnBaseCfgSw(BSC6900,BSC6910).
Configuration-based Fast Return The BSC selects LTE frequencies based on configurations when either of the following conditions is met: FASTRETURNMEASSPT(BSC6900,BSC6910) is set to OFF(Off). FASTRETURNMEASSPT(BSC6900,BSC6910) and CSFBFastReturnBaseCfgSw are set to ON(On). MSs do not support LTE frequency measurement or the BSC does not obtain MS capabilities. Configuration-based Fast Return for Ultra Flash CSFB calls is similar to that for common CSFB calls. The differences are as follows: Before sending configured LTE frequencies for an Ultra Flash CSFB call, the BSC performs both of the following decision-making processes: If LTEFastReturnFrqSendOptSw is set to ON(On), the BSC filters configured LTE frequencies based on MS capabilities. Otherwise, the BSC does not filter configured LTE frequencies. If FreqFiltBaseIRATMeasCfgSw(BSC6900,BSC6910) is set to ON(On), the BSC selects the frequencies contained in the IRAT Measurement Configuration IE from the configured LTE frequencies and includes the selected frequencies in the MI for the MS. Otherwise, the BSC does not filter configured LTE frequencies.
3.2.3 SRVCC Calls When SRVCCRapidSelSw(BSC6900,BSC6910) is set to ON(On), the BSC can implement Fast Return for SRVCC calls. Based on frequency selection modes, Fast Return for SRVCC calls is classified into measurement-based Fast Return and configuration-based Fast Return.
Measurement-based Fast Return When SRVCCRapidSelMeasOptSw(BSC6900,BSC6910) is set to ON(On) and an MS supports LTE frequency measurement, the BSC selects LTE frequencies for the MS based on the LTE frequency measurement result. Figure 3-1 shows the procedure for implementing measurement-based Fast Return. Measurement-based Fast Return for SRVCC calls is similar to that for CSFB calls. The only difference lies in the neighboring LTE cell frequencies contained in the Measurement Information message. If FreqFiltBaseIRATMeasCfgSw(BSC6900,BSC6910) is set to ON(On), the BSC selects the frequencies contained in the IRAT Measurement Configuration IE from the configured LTE frequencies and includes the selected frequencies in the MI for the MS. Otherwise, the BSC does not filter configured LTE frequencies. The BSC includes LTE frequencies and measurement information in the MI based on MS capabilities. If MSs do not support LTE frequency measurement or the BSC does not obtain MS capabilities, the BSC determines whether to trigger configuration-based Fast Return based on the value of SRVCCReseleBaseCfgSw(BSC6900,BSC6910).
Configuration-based Fast Return The BSC selects LTE frequencies based on configurations when all of the following conditions are met: SRVCCRapidSelMeasOptSw(BSC6900,BSC6910) is set to ON(On). MSs do not support LTE frequency measurement or the BSC does not obtain MS capabilities. SRVCCRapidSelBaseCfgSw(BSC6900,BSC6910) is set to ON(On). The procedure for implementing configuration-based Fast Return is similar to that for implementing measurement-based Fast Return. The differences are as follows:
The configuration-based Fast Return does not involve the Measurement Information and Measurement Report messages. During configuration-based Fast Return, the Channel Release message contains the frequencies of the neighboring LTE cells whose SPTRAPIDSEL(BSC6900,BSC6910) is set to SUPPORT(SUPPORT). The frequencies are configured when those LTE cells are added. Before sending configured LTE frequencies for an SRVCC call, the BSC performs both of the following decision-making processes:
If LTEFastReturnFrqSendOptSw(BSC6900,BSC6910) is set to ON(On), the BSC filters configured LTE frequencies based on MS capabilities. Otherwise, the BSC does not filter configured LTE frequencies.
If FreqFiltBaseIRATMeasCfgSw(BSC6900,BSC6910) is set to ON(On), the BSC selects the frequencies contained in the IRAT Measurement Configuration IE from the configured LTE frequencies and includes the selected frequencies in the MI for the MS. Otherwise, the BSC does not filter configured LTE frequencies.
3.3 Specifications Number of Configured Neighboring Cell Frequencies If CELL2GBA1OPTSW(BSC6900,BSC6910) and CELL2GBA2OPTSW(BSC6900,BSC6910) are set to ON(On), the BSC checks the number of neighboring GSM cell frequencies. The number cannot exceed the specifications listed in Table 3-1. For details, see section 10.5.2.20 "Measurement Results" in 3GPP TS 44.018 V10.8.0. Table 3-1 Specifications of the number of neighboring GSM cell frequencies Cell Type
Common cell MOCN-enabled cell
Maximum Number of Neighboring GSM Cell Frequencies
Remarks
MAX(31 – N, 28)
N indicates the total number of neighboring LTE cell frequencies. Its Maximum number of neighboring GSM cell maximum number is 8. An MS can measure a maximum of three frequencies configured for an operator: neighboring LTE cell frequencies. MAX(31 – N, 28)
If CELL2GBA1OPTSW(BSC6900,BSC6910) and CELL2GBA2OPTSW(BSC6900,BSC6910) are set to OFF(Off) and the number of configured neighboring GSM cell frequencies does not meet the specifications, information about the neighboring LTE cells cannot be properly reported.
Number of Frequencies Carried in the Channel Release Message A maximum of eight LTE cell frequencies can be carried in the Channel Release message.
4 Related Features 4.1 Prerequisite Features GBFD-511301 Cell Reselection Between GSM and LTE The GBFD-511312 Fast LTE Reselection at 2G CS Call Release feature requires the GBFD-511301 Cell Reselection Between GSM and LTE feature.
4.2 Mutually Exclusive Features
None.
4.3 Impacted Features CSFB It is recommended that this feature be enabled with the GBFD-511313 CSFB or GBFD-171212 UltraFlash CSFB feature because the combination achieves the following gains: Fast return to an LTE cell after an MS terminates a CSFB call Increased duration in which an MS camps on an LTE cell Decreased number of times that an MS processes services in GSM cells Increased overall capacities of GSM and LTE networks If a CSFB mobile terminated call (MTC) performs a location update when returning to a GSM cell, Fast LTE Reselection at 2G CS Call Release can be enabled for MSs in compliance with 3GPP Release 8 or Release 9 by setting GLFRCSMTLAUMode(BSC6900,BSC6910): If R8_MS_SWITCH is selected, an MS in compliance with 3GPP Release 8 can fast return to the LTE network when the call is released due to location update in the CSFB procedure. If R9_MS_SWITCH is selected, an MS in compliance with 3GPP Release 9 or later can fast return to the LTE network when the call is released due to location update in the CSFB procedure.
SRVCC It is recommended that this feature be enabled with the GBFD-511309 SRVCC feature because the combination achieves the following gains: Fast return to an LTE cell after an MS terminates an SRVCC call Increased duration in which an MS camps on an LTE cell Decreased number of times that an MS processes services in GSM cells Increased overall capacities of GSM and LTE networks
DTM Fast LTE Reselection at GSM CS Call Release can be enabled in non-DTM and non-enhanced DTM scenarios but cannot be enabled in an enhanced DTM scenario: In a non-DTM scenario, the network or MS does not support DTM. After an MS terminates a call in a GSM cell, the BSC sends the MS a Channel Release message that carries the frequency information about neighboring LTE cells. Based on the frequency information, the MS reselects a neighboring LTE cell on the specified frequencies. In a non-enhanced DTM scenario, both the network and MS support DTM but one of them does not support enhanced DTM. Therefore, the network or MS does not support the enhanced DTM CS release procedure. The MS releases CS and PS services simultaneously. The BSC sends the MS a Channel Release message that carries the frequency information about neighboring LTE cells. Based on the frequency information, the MS reselects a neighboring LTE cell on the specified frequencies.
In an enhanced DTM scenario, the network and MS support enhanced DTM. Therefore, they support the enhanced DTM CS release procedure. The BSC does not send the Channel Release message while releasing CS or PS services. Therefore, this feature does not take effect in the enhanced DTM CS release procedure scenario. NOTE: Huawei BSC does not support enhanced DTM. To enable or disable the DTM feature for a BSC, run the SET GCELLGPRS command.
MOCN In cells enabled with GBFD-118702 MOCN Shared Cell or GBFD-160212 MOCN II, the BSC filters neighboring LTE cells by operator and sends only neighboring LTE cells that belong to the operator serving the MS. This prevents cell reselection failures caused by the situation where the neighboring LTE cells corresponding to the frequencies measured by an MS do not belong to the operator serving the MS. When FASTRETURNMEASSPT(BSC6900,BSC6910) is set to ON(On):
IfLTEUseShaSw(BSC6900,BSC6910) is set to ON(On), the BSC filters neighboring LTE cells based on the shared handover areas (SHAs).
If LTEUseShaSw(BSC6900,BSC6910) is set to OFF(Off), the BSC filters neighboring LTE cells based on the operators configured for these neighboring LTE cells.
When FASTRETURNMEASSPT(BSC6900,BSC6910) is set to OFF(Off):
If FASTRETURNFILTERSW(BSC6900,BSC6910) is set to ON(On), the BSC filters neighboring LTE cells based on the operators configured for these neighboring LTE cells.
If FASTRETURNFILTERSW(BSC6900,BSC6910) is set to OFF(Off), the BSC sends all neighboring LTE cell information to MSs without any filtering.
Mobility Management Based on IMSI for Multiple Operators When the GBFD-171209 Mobility Management Based on IMSI for Multiple Operators feature is enabled, the BSS categorizes MSs by their operators based on international mobile subscriber identities (IMSIs) and customizes policies for fast LTE reselection at GSM call release based on MS categories. For details, see Mobility Management Based on IMSI for Multiple Operators Feature Parameter Description.
5 Network Impact 5.1 System Capacity Enabling both Fast LTE Reselection at 2G CS Call Release and GBFD-511313 CSFB, GBFD-171212 Ultra-Flash CSFB, or GBFD-511309 SRVCC has the following impacts on system capacity: Shortens the period during which an MS camps on a GSM cell. Decreases the number of times that an MS processes services in GSM cells. Increases the overall capacities of GSM and LTE networks.
5.2 Network Performance Fast LTE Reselection at 2G CS Call Release has the following impacts on network performance: Enables an MS to return to the LTE network immediately after terminating a call in a GSM cell. Decreases the number of location updates on the GSM network.
Decreases the time an MS takes to return to an LTE cell. Improves user experience. When the BSC selects LTE frequencies for an MS based on configurations, if the signal strength of configured LTE frequencies is poor, the MS cannot camp on cells working on the specified frequencies. In this case, the MS must reselect an appropriate GSM or LTE cell to camp on. The MS determines the period to search for frequencies of neighboring LTE cells. During this period, the MS is out of service, and it cannot make or answer calls because this may decrease the paging success rate.
6 Engineering Guidelines 6.1 When to Use Fast LTE Reselection at 2G CS Call Release It is recommended that this feature be enabled when an MS falls back to a GSM network from the LTE network to perform CS services.
6.2 Required Information None
6.3 Network Planning When FASTRETURNMEASSPT(BSC6900,BSC6910) is set to ON(On), the fast selection based on neighboring LTE cell measurement is supported. To ensure that MSs properly report neighboring LTE cell information, plan an appropriate number of neighboring GSM cell frequencies. For details about the specifications of the number of neighboring GSM cell frequencies, see Table 3-1.
6.4 Deploying Fast LTE Reselection at GSM CS Call Release 6.4.1 Deployment Requirements Table 6-1 Deployment Requirements Aspect
Requirem
Related features
See 4 Rel
BSC
None
BTS
For Ultra-F
GSM networking
The netwo
MS
MSs supp If the fast When Dec Fo
Fo When Dec To apply th MSC
To apply th
Aspect
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Others
None
6.4.2 Activation Using MML Commands Enabling Fast Return for common CSFB calls and Ultra Flash CSFB calls 1. On the BSC LMT, run the ADD GEXTLTECELL command to add an external LTE cell (cell 1). 2. (Optional) If the the optimization of LTE frequency sending when an MS fast returns to an LTE cell is required, run the SET GCELLOTHBASIC command with LTE Fast Reselect Freq Send Optimize Switch set to ON(On) for GSM cell 0. If Fast Return for Ultra Flash CSFB calls is to be enabled, you also need to set Inter-RAT Meas Config Based LTE Freq Filter Sw to ON(On). 3. If LTE frequencies contained in the Channel Release message are obtained from configuration commands, perform the following operations: a. Run the ADD GLTENCELL command to configure LTE cell 1 as the neighboring cell of GSM cell 0. In this step, set Support Rapid Reselection to SUPPORT(SUPPORT) for LTE cell 1. b. Run the SET GCELLPRIEUTRANSYS command with Support Measurement-based Fast LTE Reselect to OFF(Off) for GSM cell 0. If GSM cell 0 is an MOCN-enabled cell, you also need to set LTE Neighbor Cell Filter for Fast Reselection to ON(On). c. Run the SET GCELL2GBA1 command with 2G BA1 Neighboring Cell Optimization Switch set to ON(On). d. Run the SET GCELLHO2GBA2 command with 2G BA2 Neighboring Cell Optimization Switch set to ON(On). If LTE frequencies contained in the Channel Release message are obtained from MRs, perform the following operations: e. Run the ADD GLTENCELL command to configure LTE cell 1 as the neighboring cell of GSM cell 0. In this step, set Support Rapid Reselection to SUPPORT(SUPPORT) for LTE cell 1. f. Run the SET GCELLPRIEUTRANSYS command with Support Measurement-based Fast LTE Reselect to ON(On) for GSM cell 0. g. (Optional) To enable configuration-based fast reselection when MSs do not support LTE frequency measurement, run the SET GCELLCSFBPARA command with Config Based CSFB Fast Reselect Opt Switch set to ON(On) for GSM cell 0. h. Run the SET GCELL2GBA1 command with 2G BA1 Neighboring Cell Optimization Switch set to ON(On). i. Run the SET GCELLHO2GBA2 command with 2G BA2 Neighboring Cell Optimization Switch set to ON(On). NOTE:
GSM cell 0 must be configured as a neighboring cell of LTE cell 1 on the LTE side. Set Support Measurement-based Fast LTE Reselect to ON(On) only when the MS can measure neighboring LTE cells in GSM CS connected mode. To enable the Channel Release message to contain multiple frequencies of neighboring LTE cells, set Support Rapid Reselection to SUPPORT(SUPPORT) for multiple neighboring LTE cells as required. 4. Run the SET BSCBASIC command with A Interface Tag, Um Interface Tag, and Abis Interface Tag set to GSM_PHASE_2Plus. 5. Run the SET GCELLPRIEUTRANSYS command with EUTRAN Priority set to a value greater than that of UTRAN Priority for GSM cell 0. 6. (Optional) If a local area update (LAU) is performed during the CSFB procedure of an MTC to the GSM network, to ensure that this feature takes effect for MSs in compliance with 3GPP Releases 8 and 9, run the SET BSCEXSOFTPARA command with R8_MS_SWITCH and R9_MS_SWITCH selected for LAU Gl Fast Return Mode. NOTE: R9_MS_SWITCH is selected by default. That is, this feature takes effect for MSs complying with 3GPP Release 9 by default. R8_MS_SWITCH is deselected by default. That is, this feature does not take effect for MSs complying with 3GPP Release 8 by default. If there are MSs complying with 3GPP Release 8 on the live network, select R8_MS_SWITCH. Enabling Fast Return for SRVCC calls 1. On the BSC LMT, run the ADD GEXTLTECELL command to add an external LTE cell (cell 1). 2. Run the ADD GLTENCELL command to configure LTE cell 1 as the neighboring cell of GSM cell 0. In this step, set Support Rapid Reselection to SUPPORT(SUPPORT) for LTE cell 1. 3. Run the SET GCELLSRVCC command with SRVCC Fast Reselect to LTE Switch, SRVCC Fast Reselect Meas Optimize Switch, and Config Based SRVCC Fast Reselect Switch set to ON(On) for GSM cell 0. Set Inter-RAT In HO SRVCC Stat Switch based on the actual situation. 4. Run the SET GCELLOTHBASIC command with LTE Fast Reselect Freq Send Optimize Switch and Inter-RAT Meas Config Based LTE Freq Filter Sw set to ON(On) for GSM cell 0. 5. Run the SET GCELL2GBA1 command with 2G BA1 Neighboring Cell Optimization Switch set to ON(On). 6. Run the SET GCELLHO2GBA2 command with 2G BA2 Neighboring Cell Optimization Switch set to ON(On).
MML Command Examples Enabling Fast Return for common CSFB calls If LTE frequencies contained in the Channel Release message are obtained from configuration commands: ADD GEXTLTECELL: EXTLTECELLID=8048, EXTLTECELLNAME="Cell1", MCC="460", MNC="10", ENODEBTYPE=MACRO, CI=0, TAC=1, FREQ=100, PCID=0, EUTRANTYPE=FDD; SET GCELLOTHBASIC: IDTYPE=BYNAME, CELLNAME=Ce110, LTEFastReturnFrqSendOptSw=ON;
ADD GLTENCELL: IDTYPE=BYNAME, SRCLTENCELLNAME="Ce110", NBRLTENCELLNAME="Cell1", SPTRESEL=SUPPORT, SPTRAPIDSEL=SUPPORT; SET GCELLPRIEUTRANSYS: IDTYPE=BYNAME, CELLNAME="Ce110", FASTRETURNMEASSPT=OFF; SET GCELL2GBA1: IDTYPE=BYNAME, CELLNAME="Cell0", CELL2GBA1TAG=AUTO, CELL2GBA1OPTSW=ON; SET GCELLHO2GBA2: IDTYPE=BYNAME, CELLNAME="Ce110", CELL2GBA2TAG=AUTO, CELL2GBA2OPTSW=ON; SET BSCBASIC: AVer=GSM_PHASE_2Plus, AbisVer=GSM_PHASE_2Plus, UmVer=GSM_PHASE_2Plus; SET GCELLPRIEUTRANSYS: IDTYPE=BYNAME, CELLNAME=Ce110, UTRANPRI=0, EUTRANPRI=1; SET BSCEXSOFTPARA: GLFRCSMTLAUMode=R8_MS_SWITCH-1&R9_MS_SWITCH-1; If LTE frequencies contained in the Channel Release message are obtained from MRs: ADD GEXTLTECELL: EXTLTECELLID=8048, EXTLTECELLNAME="Cell1", MCC="460", MNC="10", ENODEBTYPE=MACRO, CI=0, TAC=1, FREQ=100, PCID=0, EUTRANTYPE=FDD; ADD GLTENCELL: IDTYPE=BYNAME, SRCLTENCELLNAME="Ce110", NBRLTENCELLNAME="Cell1", SPTRAPIDSEL =SUPPORT; SET GCELLOTHBASIC: IDTYPE=BYNAME, CELLNAME=Ce110, LTEFastReturnFrqSendOptSw=ON; ADD GLTENCELL: IDTYPE=BYNAME, SRCLTENCELLNAME="Ce110", NBRLTENCELLNAME="Cell1", SPTRESEL=SUPPORT, SPTRAPIDSEL=SUPPORT; SET GCELLPRIEUTRANSYS: IDTYPE=BYNAME, CELLNAME="Ce110", FASTRETURNMEASSPT=ON; SET GCELLCSFBPARA: IDTYPE=BYNAME, CELLNAME=Ce110, CSFBFastReturnBaseCfgSw=ON; SET GCELL2GBA1: IDTYPE=BYNAME, CELLNAME="Cell0", CELL2GBA1TAG=AUTO, CELL2GBA1OPTSW=ON; SET GCELLHO2GBA2: IDTYPE=BYNAME, CELLNAME="Ce110", CELL2GBA2TAG=AUTO, CELL2GBA2OPTSW=ON; SET BSCBASIC: AVer=GSM_PHASE_2Plus, AbisVer=GSM_PHASE_2Plus, UmVer=GSM_PHASE_2Plus; SET GCELLPRIEUTRANSYS: IDTYPE=BYNAME, CELLNAME=Ce110, UTRANPRI=0, EUTRANPRI=1; SET BSCEXSOFTPARA: GLFRCSMTLAUMode=R8_MS_SWITCH-1&R9_MS_SWITCH-1; Enabling Fast Return for Ultra Flash CSFB calls If LTE frequencies contained in the Channel Release message are obtained from configuration commands: ADD GEXTLTECELL: EXTLTECELLID=8048, EXTLTECELLNAME="Cell1", MCC="460", MNC="10", ENODEBTYPE=MACRO, CI=0, TAC=1, FREQ=100, PCID=0, EUTRANTYPE=FDD; SET GCELLOTHBASIC: IDTYPE=BYNAME, CELLNAME="Cell0", LTEFastReturnFrqSendOptSw=ON, FreqFiltBaseIRATMeasCfgSw=ON; ADD GLTENCELL: IDTYPE=BYNAME, SRCLTENCELLNAME="Ce110", NBRLTENCELLNAME="Cell1", SPTRESEL=SUPPORT, SPTRAPIDSEL=SUPPORT; SET GCELLPRIEUTRANSYS: IDTYPE=BYNAME, CELLNAME="Ce110", FASTRETURNMEASSPT=OFF;
SET GCELL2GBA1: IDTYPE=BYNAME, CELLNAME="Cell0", CELL2GBA1TAG=AUTO, CELL2GBA1OPTSW=ON; SET GCELLHO2GBA2: IDTYPE=BYNAME, CELLNAME="Ce110", CELL2GBA2TAG=AUTO, CELL2GBA2OPTSW=ON; SET BSCBASIC: AVer=GSM_PHASE_2Plus, AbisVer=GSM_PHASE_2Plus, UmVer=GSM_PHASE_2Plus; SET GCELLPRIEUTRANSYS: IDTYPE=BYNAME, CELLNAME=Ce110, UTRANPRI=0, EUTRANPRI=1; If LTE frequencies contained in the Channel Release message are obtained from MRs: ADD GEXTLTECELL: EXTLTECELLID=8048, EXTLTECELLNAME="Cell1", MCC="460", MNC="10", ENODEBTYPE=MACRO, CI=0, TAC=1, FREQ=100, PCID=0, EUTRANTYPE=FDD; ADD GLTENCELL: IDTYPE=BYNAME, SRCLTENCELLNAME="Ce110", NBRLTENCELLNAME="Cell1", SPTRAPIDSEL =SUPPORT; SET GCELLOTHBASIC: IDTYPE=BYNAME, CELLNAME=Ce110, LTEFastReturnFrqSendOptSw=ON; ADD GLTENCELL: IDTYPE=BYNAME, SRCLTENCELLNAME="Ce110", NBRLTENCELLNAME="Cell1", SPTRAPIDSEL =SUPPORT; SET GCELLPRIEUTRANSYS: IDTYPE=BYNAME, CELLNAME="Ce110", FASTRETURNMEASSPT=ON; SET GCELLCSFBPARA: IDTYPE=BYNAME, CELLNAME=Ce110, CSFBFastReturnBaseCfgSw=ON; SET GCELL2GBA1: IDTYPE=BYNAME, CELLNAME="Cell0", CELL2GBA1TAG=AUTO, CELL2GBA1OPTSW=ON; SET GCELLHO2GBA2: IDTYPE=BYNAME, CELLNAME="Ce110", CELL2GBA2TAG=AUTO, CELL2GBA2OPTSW=ON; SET BSCBASIC: AVer=GSM_PHASE_2Plus, AbisVer=GSM_PHASE_2Plus, UmVer=GSM_PHASE_2Plus; SET GCELLPRIEUTRANSYS: IDTYPE=BYNAME, CELLNAME=Ce110, UTRANPRI=0, EUTRANPRI=1; Enabling Fast Return for SRVCC calls ADD GEXTLTECELL: EXTLTECELLID=8048, EXTLTECELLNAME="Cell1", MCC="460", MNC="10", ENODEBTYPE=MACRO, CI=0, TAC=1, FREQ=100, PCID=0, EUTRANTYPE=FDD; ADD GLTENCELL: IDTYPE=BYNAME, SRCLTENCELLNAME="Ce110", NBRLTENCELLNAME="Cell1", SPTRESEL=SUPPORT, SPTRAPIDSEL=SUPPORT; SET GCELLSRVCC: IDTYPE=BYNAME, CELLNAME="Cell0", SRVCCRapidSelSw=ON, SRVCCRapidSelMeasOptSw=ON, SRVCCRapidSelBaseCfgSw=ON, SRVCCStatInterRanHo=ON; SET GCELLOTHBASIC: IDTYPE=BYNAME, CELLNAME="Cell0", LTEFastReturnFrqSendOptSw=ON, FreqFiltBaseIRATMeasCfgSw=ON; SET GCELL2GBA1: IDTYPE=BYNAME, CELLNAME="Cell0", CELL2GBA1TAG=AUTO, CELL2GBA1OPTSW=ON; SET GCELLHO2GBA2: IDTYPE=BYNAME, CELLNAME="Ce110", CELL2GBA2TAG=AUTO, CELL2GBA2OPTSW=ON;
Using the CME (Method 1) NOTE: When configuring the Fast LTE Reselection at 2G CS Call Release feature on the CME, perform a single configuration first, and then perform a batch modification if required. Configure the parameters of a single
object before a batch modification. Perform a batch modification before logging out of the parameter setting interface. 1. Configure a single object (such as a cell) on the CME. Set parameters on the CME according to the operation sequence in Table 6-2. For instructions on how to perform the CME single configuration, see CME Single Configuration Operation Guide. 2. (Optional) Modify objects in batches on the CME. (CME batch modification center) To modify objects in batches, click on the CME to start the batch modification wizard. For instructions on how to perform a batch modification through the CME batch modification center, press F1 on the wizard interface to obtain online help. Table 6-2 Configuring parameters on the CME SN
MO
1
GEXTLTECELL
2
GCELLOTHBASIC
3
GCELLCSFBPARA
4
GCELLSRVCC
5
GLTENCELL GCELLPRIEUTRANSYS GCELLPRIEUTRANSYS
SN
MO GCELL2GBA1 GCELLHO2GBA2
6
BSCBASIC
7
GCELLPRIEUTRANSYS
8
BSCEXSOFTPARA
Using the CME (Method 2) This feature can be batch activated using the CME. For detailed operations, see the following section in the CME product documentation or online help: Managing the CME > CME Guidelines > Enhanced Feature Management > Feature Operation and Maintenance.
6.4.3 Activation Observation Monitoring Counters Common CSFB calls or Ultra Flash CSFB calls Monitor the counter listed in Table 6-3. If the value of this counter is not 0, the Fast Return for CSFB calls has taken effect for common CSFB calls or Ultra Flash CSFB calls. Table 6-3 Counter to be observed
CELL.CSFB.FAST.RETURN.NUM SRVCC calls Monitor the counter listed in Table 6-4. If the value of this counter is not 0, the Fast Return for SRVCC calls has taken effect for SRVCC calls. Table 6-4 Counter to be observed
CELL.SRVCC.FAST.RETURN.NUM
Tracing Signaling 1. On the BSC LMT, start Um interface message tracing. Use an MS that camps on GSM cell 0 to initiate a call and hold the call.
2. Release the call and view the network identifier on the MS. Expected result: The network identifier on the MS shows that the MS has camped on an LTE cell. NOTE: If the GSM and LTE networks use the same network identifier, the MS must allow users to query whether its currently camped cell is a GSM or an LTE cell. 3. Trace CS messages over the Um interface. Expected result: The downlink Channel Release message over the Um interface contains the "cell-selection-indicator-after-release" IE. The IE contains information about neighboring LTE cells, as shown in Figure 6-1. Figure 6-1 Channel Release trace result
6.4.4 Deactivation Using MML Commands On the BSC LMT, run the MOD GLTENCELL with Support Rapid Reselection set to UNSUPPORT(UNSUPPORT) for each neighboring LTE cell.
MML Command Examples MOD GLTENCELL: IDTYPE=BYNAME, SRCLTENCELLNAME="Ce110", NBRLTENCELLNAME="Cell1", SPTRAPIDSEL =UNSUPPORT;
Using the CME NOTE: When configuring the Fast LTE Reselection at 2G CS Call Release feature on the CME, perform a single configuration first, and then perform a batch modification if required. Configure the parameters of a single object before a batch modification. Perform a batch modification before logging out of the parameter setting interface. 1. Configure a single object (such as a cell) on the CME. Set the parameter described in Table 6-5 on the CME. For instructions on how to perform the CME single configuration, see CME Single Configuration Operation Guide.
2. (Optional) Modify objects in batches on the CME. (CME batch modification center) To modify objects in batches, click on the CME to start the batch modification wizard. For instructions on how to perform a batch modification through the CME batch modification center, press F1 on the wizard interface to obtain online help. Table 6-5 Configuring the parameter on the CME SN 1
GLTE
6.5 Performance Monitoring 1. Monitor counters.
Common CSFB calls and Ultra Flash CSFB calls Monitor the counters listed in Table 6-6 to observe the number of times CSFB MSs fast return to the LTE network. Table 6-6 Counters to be observed
CELL.CSFB.FAST.RETURN.NUM CELL.CSFB.BLIND.FAST.RETURN.NUM
SRVCC calls Monitor the counters listed in Table 6-7 to observe the number of times SRVCC MSs fast return to the LTE network. Table 6-7 Counters to be observed
CELL.SRVCC.FAST.RETURN.NUM CELL.SRVCC.BLIND.FAST.RETURN.NUM 2. From the MS's logs, check the GSM-to-LTE cell reselection duration. That is, check the duration from when the MS receives the Channel Release message from the BSC on the GSM network to when the MS sends the RRC CONNECTION REQUEST message on the LTE network. Expected result: The GSM-to-LTE cell reselection duration decreases after this feature is enabled.
6.6 Parameter Optimization If the signal quality on the LTE network is poor, an MS may fail to return to the LTE network. To resolve this problem, adjust parameter settings using either of the following methods:
If the MS can measure neighboring LTE cells in GSM CS connected mode, run the SET GCELLPRIEUTRANSYS command with FASTRETURNMEASSPT(BSC6900,BSC6910) set to ON(On) for cell 0. Set SPTRAPIDSEL(BSC6900,BSC6910) to UNSUPPORT(UNSUPPORT) to disable Fast LTE Reselection at 2G CS Call Release.
