CSFB主被叫信令流程介绍

CSFallback基本信令介绍2015.May.26郑州联合注册流程CSFB主被叫流程联合跟踪区更新流程SIM2G4GBTSBSCMSSeNodeBMMEBTS/NODEBBSC/RNCMSSeNodeBMMESIM2G4GHLRHLR单卡双待手机CSFB手机在2/3G及4G网络同时注册数据业务用4G网络语音业务用2/3G网络，接续时延短2/3G与LTE无需互操作仅在4G网络注册进行主被叫时回落到GSM/TDS网络，结束后再返回4G网络。接续时延稍长单卡双待与CSFB手机的注册联合EPS/IMSI附着流程Attachrequest(CombinedEPS/IMSIattach,GUTI,UEcapacity,TAI,LAI)S6a-UpdateLocationRequest(MMEname,IMSI)S6a-UpdateLocationAccept(NAM=PACKET_AND_CIRCUIT)CreateSessionreq(IMSI,MSISDN,QoS,APN)SGsAP-UpdateLocationRequest(LAI，IMSI,MMEaddress)LocationUpdateinCSdomainSGsAP-UpdateLocationAccept(VLRNum,TMSI)InitialContextSetupRequest+AttachAccept(combinedEPS/IMSIattach,TAI,GUTI,LAI,TMSI,)+ActivateDefaultEPSBearerContextRequest(QCI,APN,PDNADDRESS,QOS,APN-AMBR)AttachCompleteCreateSessionresp(PDNadd,TEID-C,TEID-U,EBI)eNBUEMMEMSC/VLRS/P-GWHSSInitialUEmessage+AttachRequest+PDNconnectivityRequestRandomAccessSequenceRRCConnectionSetupCompleteRRCConnectionSetupRequestRRCConnectionRequestRRC连接建立Identityrequest/responseTAI-LAI-MSC/VLRSecurityModeCommandUECapabilityEnquirySecurityModeCompleteUECapabilityInformationRRCConnectionReconfiguration+AttachAccept(combinedEPS/IMSIattach,TAI,GUTI,LAI,TMSI)RRCConnectionReconfigurationCompleteInitialContextSetupResponseUECapabilityInformationIndicationActivateDefaultEPSBearerContextAcceptSecurityModeCommandSecurityModeCompleteSGsAP-TMSI-REALLOCATION-COMPLETE如果在AttachAccept包含新的TMSI如果NAM=ONLY_PACKET，MME不再向MSS发起LU流程，直接给UE回送TAUAccept如果UE支持CSFB功能，会发起附着类型”CombinedEPS/IMSIAttach”的附着请求。如果不支持CSFB功能，附着类型为”EPSAttach”。UE是否具有GERAN/UTRAN重定向能力，通知给eNodeB及MMEMME代替UE向MSS执行LU过程。如果LU过程成功，SGs的状态为SGs-ASSOCIATED。为用户建立了SGs关联，就是在VLR中存储了用户的MME地址，同时也在MME中保存了用户的VLR的地址。如在联合注册过程中，MSS给用户分配了新的TMSI，却未收到SGsAP-TMSI-REALLOCATION-COMPLETE，不影响该用户SGs的状态。CSPaging时用IMSI代替TMSI。如果UE驻留在GERAN/UTRAN时，MSS通过A/Iu正在Paging该UE。此时UE发起联合注册，MSS会停止Paging，给MME返回SGsAP-LOCATION-UPDATE-ACCEPT。LU过程不成功，MSS发SGsAP-LOCATION-UPDATE-REJECT给MME。VLR将该用户的SGs状态置为SGs-NULL。在下一次联合注册成功之前，所有的CSFB被叫被拒绝。联合注册流程CSFB主被叫流程联合跟踪区更新流程联合TAU流程TrackingAreaUpdate(TAU)Request(ActiveFlag:NoBearerestablishedReq,CombinedTA/LAUpdate,GUTI,UEcapacity,TAI,LAI)S6a-UpdateLocationRequest(MMEname,IMSI)S6a-UpdateLocationAccept(NAM=PACKET_AND_CIRCUIT)SGsAP-LOCATION-UPDATE-REQUEST(LAI，IMSI,MMEFQDN)LocationUpdateinCSdomainSGsA-LOCATIONUPDATEACCEPT(VLRNum,TMSI)TAUAccept(CombinedTA/LAUpdated,T3412,TAI,GUTI,LAI,TMSI)TAUCompleteeNBUEMMEMSC/VLRS/P-GWHSSInitialUEmessage+TAURequestRandomAccessSequenceRRCConnectionSetupCompleteRRCConnectionSetupRequestRRCConnectionRequestRRC连接建立TAI-LAI-MSC/VLRTAUAccept(CombinedTA/LAUpdated,T3412,TAI,GUTI,LAI,TMSI)UEContextReleaseCommand(NormalRelease)RRCConnectionReleaseUEContextReleaseCompleteSGsAP-TMSI-REALLOCATION-COMPLETEVLR存储MMEFQDN如果MSS/VLR收到DetachRequest或从A/Iu发起的LU，则将用户数据中的MMEFQDN删除。在下一次联合TAU或联合注册之前，VLR不再通过SGS接口进行Paging。如果在SGsAP-UpdateLocationAccept包含新的TMSI如果NAM=ONLY_PACKET，MME不再向MSS发起LU流程，直接给UE回送TAUAcceptModifyBearerRequestModifyBearerResponse联合注册流程CSFB主被叫流程联合跟踪区更新流程eNodeBMMEUEBTSBSCMSS/VLRUEHLR/HSSLTE-UuS1-MMEA-bisACS6aUmSGsCSFB主叫在4G，被叫在2/3G被叫路由主叫路由CSFB主叫流程UEeNBMMEMSSRRCConnectionSetupComplete+ExtendedServiceRequest(MOCSfallback,M-TMSI)RandomAccessSequenceRRCConnectionSetupRequestRRCConnectionSetupRRC连接建立ExtendedServiceRequestInitialContextSetupRequest(CSFallbackRequired)InitialContextSetupResponseRRCConnectionReleaseUEContextReleaseRequest(CSfallbacktriggered)UEContextReleaseCommand(CSfallbacktriggered)UEContextReleaseCompleteRedirectconsistsof3phases:–Redirectiondecisionphase(generationtriggerforredirect)–SelectionofredirecttargetbasedonUEcapabilitiesandredirectpriorities–Redirectexecution主叫流程中没有任何SGs接口信令消息Returnto2GCSFB-MO回落至2/3G后UEBTSBSCMSSCamponBTSSystemInfromationType3(LAC=xxxx)LocationUpdateRequest(Follow-onRequest,CSMOFlag)LocationUpdateAccept回落前后LAC有变化CMServiceRequest(CSMO)CMServiceAccept。。。在CSFB流程中，如果在2/3G网络中需要重新发起位置更新，手机终端需要在位置更新请求消息中加入CSMO标志，提示当前信令连接可以同时服务于后续的呼叫接续；当MSC收到终端发起的位置更新请求时，MSC需要检查请求消息中是CSMO标志：•MSS会更新相应的统计计数器。eNodeBMMEUEBTSBSCMSS/VLRUEHLR/HSSLTE-UuS1-MMEA-bisACS6aUmSGs主叫在2/3G，CSFB被叫在4G主叫路由被叫路由MSSMMEeNBUERRCConnectionSetupComplete+ExtendedServiceRequest(MTCSfallback,M-TMSI,CSFBresponse:Accept)S1AP-InitialUEMessage+Extendedservicerequest(MTCSfallback,M-TMSI,CSFBresponse:Accept,ECGI,TAI)S1AP-InitialContextSetupRequest(cs-fallback-required,LAI)S1AP-InitialContextSetupResponseS1AP-Paging(UEIdentityIndexValue:'1101101110'B,s-TMSI,cnDomain:cs,TAI)PagingResponse(CS-TMSI)CSFB-MT(UE:ECM-IDLE)RRCconnectionrelease(RedirectedCarrierInfo)SGsAP-PAGING-REQUEST(IMSI,MMEName,CSCALLIndicator,TMSI,newLAI,GlobalCN-ID)SGsAP-SERVICE-REQUEST(IMSI,CSCALLINDICATOR,TAI,ECGI,UEECMMODE:ECM-IDLE)Paging(s-TMSI,cnDomain:cs)S1AP-UEContextReleaseRequest(cs-fallback-triggered)S1AP-UEContextReleaseCommand(cs-fallback-triggered)S1AP-UEContextReleaseCompleteRandomAccessSequenceIMSImod1024S1AP连接建立S1AP连接释放RRCConnectionSetupRequestRRCConnectionSetupRRC连接建立RRC连接释放MSS:CSMT呼叫他局回落次数MSS/VLR收到来自HLR的MAP_CANCEL_LOCATION消息。StopPagingReturnto2GMME收到MSS发送的SGsAP-PAGING-REQUEST，首先在数据库里检查是否有此用户。如果可以找到该IMSI，将Paging消息通过eNo