Multi-RAB Call Drop Optimization v1.1

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Multi-RAB Call Drop Rate Optimization 15 September 2011HUAWEI TECHNOLOGIES Co., Ltd.www.huawei.comHUAWEI Confidential :40-47pt :26-30pt: :FrutigerNext LT Medium : Arial

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BackgroundPage 2The Multi-RAB services increased as smart phone penetration is increasing. General cause of drop rate of Multi-RAB higher than single CS RAB Higher RF signal quality requirement comparing with CS Single RAB More complicated signalling procedure comparing with Single RABTo improve the CS call drop Reduce the PS RF signal quality requirement for multi-RAB Reduce the loss probability due to complicated signalling process. Optimize the signalling procedures

RNC JF05 Statistics Higher CS Drop Rate for Multi-RAB scenario Significant Multi-RAB service increase across the entire network.HUAWEI TECHNOLOGIES CO., LTD.Huawei Confidential :32-35pt : R153 G0 B0 :FrutigerNext LT Medium : Arial

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2Detailed PCHR Analysis ResultPage 3MultiRAB CS Call Drop ScenariosDetailed CausePercentageSolution Drop in the procedure PS RAB Setup Procedure or PS RAB Release ProcedureSRB Reset in Security Mode1.61%19.35%Timer OptimizationSecurity Mode Expire1.61%No Solution currently. PS RAB Setup Expire9.68%Timer OptimizationSRB Reset in PS RAB Release1.61%Timer OptimizationPS RAB Release Expire3.23%Timer OptimizationRB Release and RBCU Procedure1.61%No Solution currently. Drop in case of CS+PSSRB Reset in UE8.06%69.35%Cell Update Based on UE SRB reset Neighborings Missing1.61%Neighboring optimization.The redource is not enough3.23%Solve the congesiton based on resourceSRB Reset in Compress Mode3.23%Timer OptimizationCompress Mode Complete Expire3.23%Timer OptimizationUL Link out of synchronization12.90%RF Signaling, RTWP. Solution based on RF OptimizationSRB Reset in Network1.61%Timer OptimizationASU Complete expire8.06%ASU SRB Reset8.06%IUB AAL2 Abnormal1.61%IuB transmission InvestigationMC SRB Reset6.45%Timer OptimizationPS DCCC Expire8.06%Procedure OptimizationHSDPA Cell Change Expire3.23%CS call Drop Aftger PS RAB releaseASU SRB Reset1.61%11.30%Timer OptimizationSRB Reset in UE4.84%Cell Update Based on UE SRB reset MC SRB Reset1.61%Timer OptimizationUL Link out of synchronization3.23%RF Signaling, RTWP. Solution based on RF OptimizationTotal100.00%100.00%HUAWEI TECHNOLOGIES CO., LTD.Huawei Confidential :32-35pt : R153 G0 B0 :FrutigerNext LT Medium : Arial

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3Optimization ProposalsPage 4No.Decription of OptimizationMMLPurpose1Bear UL PS service on DCH instead of HSUPA in case of multi-RABSET UCORRMALGOSWITCH: ReservedSwitch0=RESERVED_SWITCH_0_BIT11-1;Reduce the RF requirement and Simplify the Signaling Process2Reduce UL PS service Rate in case of multi-RAB SET UFRC:ULDCHBEUPPERLIMITFORAMR=D64, DLDCHBEUPPERLIMITFORAMR=D8;Reduce the RF requirement and Simplify the Signaling Process3Activate the cell update based on UE SRB ResetSET URRCTRLSWITCH: PROCESSSWITCH=RsvdPara1=RsvdBit1_BIT26-0;Optimize the procedure4Optimize PS RB Setup timerSET USTATETIMER:RBSETUPRSPTMR=10000;Reduce the call drop probability due to complicated Signaling procedure.5Optimize Active set update timerSET USTATETIMER:HOASUTMR=10000;6Optimize HSDPA service cellchange timer SET USTATETIMER:HOPHYCHRECFGTMR=10000;7Optimize RB Reconfiguration timer SET USTATETIMER:RBRECFGRSPTMR=10000;8Optimize RB REL timer expireSET USTATETIMER:RBRELRSPTMR=10000;9Optimize Cell-Update response timer SET USTATETIMER: HoCellUpdateRspTmr=10000;HUAWEI TECHNOLOGIES CO., LTD.Huawei Confidential :32-35pt : R153 G0 B0 :FrutigerNext LT Medium : Arial

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4Bear UL PS service on DCH instead of HSUPA Benefit: #1 The UL RF signal requirement of DCH is much less than HSUPA. #2 The signaling procedure is simplified because there is no HSUPA related procedures including HSUPA DCCC, HSUPA 2ms to 10 ms TTI reconfiguration, H2D handover, etc.Possible Negative Impact: Reduce UL throughput in case of CS+ PS Multi-RAB. Impact Analysis:#1 HSUPA can be used after CS release.#2 The subscriber is not sensitive to throughput when at a CS call session.

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5Page 6Bear UL PS service on DCH instead of HSUPA

Implementation in VDF SpainHUAWEI TECHNOLOGIES CO., LTD.Huawei Confidential :32-35pt : R153 G0 B0 :FrutigerNext LT Medium : Arial

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6Reduce PS service Rate forS Multi-RABBenefit: #1 Reduce the RF signal requirement of DCH. #2 The signaling procedure is simplified because of DCCC reductions.Possible Negative Impact: Reduce throughput in case of CS+ PS Multi-RAB. Impact Analysis: The subscriber is not sensitive to throughput when at a CS call session.

It has been applied in Vodacom partially (NGA & MT06).

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7Activate the Cell Update Based on UE SRB ResetBackground: The UEs with this functionality of cell update based on UE SRB Reset in this industry have been increasing recently. To support this function, Huawei optimized the procedures. The function description: According to 3GPP 25.331, UE can support Cell update based on UE SRB reset optionally.

Page 8Benefit: Reduce the call drop rate to UEs with this function. Negative Impact: Slightly more resource consumption.


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8Reduce the drop probability by timer optimization Optimize PS RB Setup timer:Benefit: Reduce the call drops for the case: #1 UE with CS connection setup PS service #2 The RB setup is sent from RNC #3 No RB setup complete response until timer expiredS #4 The CS call is released. Negative Impact: Slightly more resource consumption.

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9Reduce the drop probability by timer optimizationOptimize Active set update timer and HSDPA Cell Change timerBenefit: Reduce the call drops for the case: RNC sends the ASU (1A/1B/1C) or Serving Cell change(HSDPA), if the network cannot receive ASU complete, the call will be released. Negative Impact: Slightly more resource consumption.


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10Reduce the drop probability by timer optimizationOptimize RB Reconfiguration timerBenefit: Reduce the call drops for the case: Network sends the RB reconfiguration, if the network cannot receive the complete signalling, the call will be released. Negative Impact: Slightly some resource consumption.

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11Reduce the drop probability by timer optimizationOptimize Cell-Update response timerBenefit: Reduce the call drops for the case: RNC sends the Cell Update confirm , if the network cannot receive the complete in time, the call will be released. Negative Impact: Slightly more resource consumption. Subscriber may feel some disconnection/silence in this period. Impact Analysis: Compared with the timer in UE (8 seconds), UE will re-connect to the network rather than network waiting for even longer time. The actual subscriber perception is impacted.

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12Page 13Optimize RB REL timerBenefit: Reduce the call drops for the case: Network sends the RB Release(for PS service), if the network cannot receive the complete in time, the call will be released. . Negative Impact: Slightly more resource consumption.

Reduce the drop probability by timer optimizationHUAWEI TECHNOLOGIES CO., LTD.Huawei Confidential :32-35pt : R153 G0 B0 :FrutigerNext LT Medium : Arial

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13Page 14Thank youWelcome to visit our website:www.huawei.comCopyright2007 Huawei Technologies Co., Ltd. All Rights Reserved. The information contained in this document is for reference purpose only, and is subject to change or withdrawal according to specific customer requirements and conditions. HUAWEI TECHNOLOGIES CO., LTD.Huawei Confidential :32-35pt : R153 G0 B0 :FrutigerNext LT Medium : Arial

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14AAL Est Req(CCP)

AAL Est Ind(CCP)

SAAL

UE

NodeB

RNC

CN

RAB Ass Req

RL Recfg Prep

RL Recfg Ready

AAL2 Setup Req

AAL2 Setup Rsp

DL Sync

UL Sync

RL Recfg Commit

RB Setup

RB Setup Complete

AAL2 Setup Req

AAL2 Setup Rsp

RAB Ass Rsp

RRC

RRC

RRC

RRC

RANAP

RANAP

RANAP

RANAP

RANAP

RANAP

RANAP

RANAP

NBAP

NBAP

NBAP

NBAP

Q.AAL2

Q.AAL2

Q.AAL2

Q.AAL2

FP

FP

FP

FP

NBAP

NBAP

Multi-RAB Call Drop Optimization v1.1

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