LTE系统全网信令流程系统全网信令流程IntroductionAsanewwirelessmobilecommunicationtechnology,LTE(LongTermEvolution)provideallkindsofservicesthroughnetworkaccessprocedures.SowhenyouaretryingtounderstandtheLTEtechnology,thenetworkaccessprocedureisjustintheclosefrontofyoureyes.ThisdocumentistryingtodescribethegeneralprocedurehandlingsamongthenetworkelementsunderLTEnetworkarchitecture,bywayofshowingyoutheprocedurehandlingsinfigures.Fromthesefigures,youwillgetanoverviewoftheLTEgeneralprocedures,suchas:“TheSystemInformationHandling,“TheRandomAccessProcedure,“TheAttachProcedure,“TheTAUProcedure,“TheHandoverProcedure,etc.Thefirstseveralfiguresshowtheintroductionofprotocollayerstacksamongnetworkelements,suchas:protocollayerstacks“betweenUE-MME,“betweenUE-PDNGW,etc.Fromtheseprotocollayerstacksintroduction,youwilllearnthepeer-to-peerprotocollayersamongseveralrelatednetworkelements,itwillhelpyoutounderstandLTEproceduresworkingmechanismstuff.Andafter,beginsthedescriptionoftheLTEgeneralprocedure,inanorderfrom“Systeminformationhandlingto“ANRMeasurementprocedure,withthe“accessprocedure,“handoverprocedure,“inter-RAToperationprocedure,inthemiddle.Fromtheseprocedurefiguresdescription,youcangetthedeepdetailsoftheLTEnetworkaccessprocedure,anditwillfinallydirectyoutofoundawhole-system-viewofLTEarchitecture.ThisdocumentissuitablefortheguyswhowanttoknowtheLTEgeneralprocedure,oruseitasareferencebook.2021-11-06AbbreviationsMMEMobilityManagementEntityUEUserEquipmentMSMobileStationeNodeBevolvedNodeBGWGateWayPCRFPolicyandChargingRulesFuctionH-PCRFHome-PCRFV-PCRFVisited-PCRFHSSHomeSubscriberServerEIREquipmentIdentityRegisterUTRANUniversalTerrestrialRadioAccessNetworkE-UTRANevolvedUTRANGERANGSM/EDGERadioAccessNetworkPLMNPublicLandMobileNetworkHPLMNHomePLMNVPLMNVisitedPLMNHLRHomeLocationRegisterVLRVisitorLocationRegisterCBCCellBroadcastCentreOMCOperationandMaintenanceCenterBSCBaseStationControlerBTSBaseTransceiverStationBSSBaseStationSubsystemCNCoreNetworkMSC/SGSNMobile-servicesSwitchingCentre/ServingGPRSSupportNodeInter-RATRadioAccessTechnologyMBMSMediaBroadcastandMulticastSystemMCEMulti-cell/multicastCoordinationEntityRNCRadioNetworkControlerNetworkelementsfunctionseNodeBfunctions:-Headercompressionanduserplaneciphering;-MMEselectionwhennorouteingtoanMMEcanbedeterminedfromtheinformationprovidedbytheUE;-ULbearerlevelrateenforcementbasedonUE-AMBRandMBRviameansofuplinkscheduling(e.g.bylimitingtheamountofULresourcesgrantedperUEovertime);-DLbearerlevelrateenforcementbasedonUE-AMBR;-ULandDLbearerleveladmissioncontrol;-Transportlevelpacketmarkingintheuplink,e.g.settingtheDiffServCodePoint,basedontheQCIoftheassociatedEPSbearer.MMEfunctions:-NASsignalling;-NASsignallingsecurity;-InterCNnodesignallingformobilitybetween3GPPaccessnetworks(terminatingS3);-UEReachabilityinECM-IDLEstate(includingcontrolandexecutionofpagingretransmission);-TrackingArealistmanagement;-PDNGWandServingGWselection;-MMEselectionforhandoverswithMMEchange;-SGSNselectionforhandoversto2Gor3G3GPPaccessnetworks;-Roaming(S6atowardshomeHSS);-Authentication;-Authorization;-Bearermanagementfunctionsincludingdedicatedbearerestablishment;-LawfulInterceptionofsignallingtraffic;-Warningmessagetransferfunction(includingselectionofappropriateeNB);UEReachabilityprocedures.SGSNfunctions:-InterEPCnodesignallingformobilitybetween2G/3GandE-UTRAN3GPPaccessnetworks;-PDNandServingGWselection:theselectionofS GW/P GWbytheSGSNisasspecifiedfortheMME;MMEselectionforhandoverstoE-UTRAN3GPPaccessnetwork.NetworkelementsfunctionsServingGWfunctions:-thelocalMobilityAnchorpointforinter-eNodeBhandover;-sendingofoneormoreendmarkertothesourceeNodeB,sourceSGSNorsourceRNCimmediatelyafterswitchingthepathduringinter-eNodeBandinter-RAThandover,especiallytoassistthereorderingfunctionineNodeB.-Mobilityanchoringforinter-3GPPmobility(terminatingS4andrelayingthetrafficbetween2G/3GsystemandPDNGW);-ECM-IDLEmodedownlinkpacketbufferingandinitiationofnetworktriggeredservicerequestprocedure;-LawfulInterception;-Packetrouteingandforwarding;-Transportlevelpacketmarkingintheuplinkandthedownlink,e.g.settingtheDiffServCodePoint,basedontheQCIoftheassociatedEPSbearer;-Accountingforinter-operatorcharging.ForGTP-basedS5/S8,theServingGWgeneratesaccountingdataperUEandbearer;-InterfacingOFCSaccordingtochargingprinciplesandthroughreferencepointsspecifiedinTS32.24051.PDNGWfunctions:-Per-userbasedpacketfiltering(bye.g.deeppacketinspection);-LawfulInterception;-UEIPaddressallocation;-Transportlevelpacketmarkingintheuplinkanddownlink,e.g.settingtheDiffServCodePoint,basedontheQCIoftheassociatedEPSbearer;-Accountingforinter-operatorcharging;-ULandDLservicelevelchargingasdefinedinTS23.2036(e.g.basedonSDFsdefinedbythePCRF,orbasedondeeppacketinspectiondefinedbylocalpolicy);-InterfacingOFCSthroughaccordingtochargingprinciplesandthroughreferencepointsspecifiedinTS32.24051.-ULandDLservicelevelgatingcontrolasdefinedinTS23.2036;-ULandDLservicelevelrateenforcementasdefinedinTS23.2036(e.g.byratepolicing/shapingperSDF);-ULandDLrateenforcementbasedonAPN-AMBR(e.g.byratepolicing/shapingperaggregateoftrafficofallSDFsofthesameAPNthatareassociatedwithNon-GBRQCIs);Networkelementsfunctions-DLrateenforcementbasedontheaccumulatedMBRsoftheaggregateofSDFswiththesameGBRQCI(e.g.byratepolicing/shaping);-DHCPv4(serverandclient)andDHCPv6(clientandserver)functions;-ThenetworkdoesnotsupportPPPbearertypeinthisversionofthespecification.Pre-Release8PPPfunctionalityofaGGSNmaybeimplementedinthePDNGW;-packetscreening.-ULandDLbearerbindingasdefinedinTS23.2036;-ULbearerbindingverificationasdefinedinTS23.2036;-FunctionalityasdefinedinRFC486132;-AccountingperUEandbearer.H-PCRFfunctions:-terminatestheRxreferencepointforhomenetworkservices;-terminatestheS9referencepointforroamingwithlocalbreakout;-associatesthesessionsestablishedoverthemultiplereferencepoints(S9,Rx),forthesameUEsIP-CANsession(PCCsessionbinding).V-PCRFfunctions:-terminatestheGxandS9referencepointsforroamingwithlocalbreakout;-terminatesRxforroamingwithlocalbreakoutandvisitedoperatorsApplicationFunction.网元间信令面总体协议栈网元间信令面总体协议栈续网元间用户面总体协议栈网元间用户面总体协议栈续系统音讯广播流程Specialcomments:Thefrozendataoffiducial3GPPprotocolversion:2021/09.Systeminformationhandling:SysteminformationisdividedintotheMasterInformationBlock(MIB)andanumberofSystemInformationBlocks(SIBs).TheMIBincludesalimitednumberofmostessentialandmostfrequentlytransmittedparametersthatareneededtoacquireotherinformationfromthecell,andistransmittedonBCH.SIBsotherthanSystemInformationBlockType1arecarriedinSystemInformation(SI)messagesandmappingofSIBstoSImessagesisflexiblyconfigurablebyschedulingInfoListincludedinSystemInformationBlockType1,withrestrictionsthat:eachSIBiscontainedonlyinasingleSImessage,onlySIBshavingthesameschedulingrequirement(periodicity)canbemappedtothesameSImessage,andSystemInformationBlockType2isalwaysmappedtotheSImessagethatcorrespondstothefirstentryinthelistofSImessagesinschedulingInfoList.TheremaybemultipleSImessagestransmittedwiththesameperiodicity.SystemInformationBlockType1andallSImessagesaretransmittedonDL-SCH.Reference:36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification;小区选择流程1)InitialCellSelection:ThisprocedurerequiresnopriorknowledgeofwhichRFchannelsareE-UTRAcarriers.TheUEshallscanallRFchannelsintheE-UTRAbandsaccordingtoitscapabilitiestofindasuitablecell.Oneachcarrierfrequency,theUEneedonlysearchforthestrongestcell.Onceasuitablecellisfoundthiscellshallbeselected.2)StoredInformationCellSelection:Thisprocedurerequiresstoredinformationofcarrierfrequenciesandoptionallyalsoinformationoncellparameters,frompreviouslyreceivedmeasurementcontrolinformationelementsorfrompreviouslydetectedcells.OncetheUEhasfoundasuitablecelltheUEshallselectit.IfnosuitablecellisfoundtheInitialCellSelectionprocedureshallbestarted.suitablecell:AsuitablecellisacellonwhichtheUEmaycampontoobtainnormalservice.Suchacellshallfulfilallthefollowingrequirements.-Thecellispartofeither:-theselectedPLMN,or:-theregisteredPLMN,or:-aPLMNoftheEquivalentPLMNlistaccordingtothelatestinformationprovidedbyNAS:-Thecellisnotbarred-ThecellispartofatleastoneTAthatisnotpartofthelistofforbiddentrackingareasforroaming,whichbelongstoaPLMNthatfulfilsthefirstbulletabove;-Thecellselectioncriteriaarefulfilled;-ForaCSGcell,theCSGIDispartoftheallowedCSGlistoftheUE.IfmorethanonePLMNidentityisbroadcastinthecell,thecellisconsideredtobepartofallTAswithTAIsconstructedfromthePLMNidentitiesandtheTACbroadcastinthecell.Reference:36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification;36.304:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);Equipment(UE)proceduresinidlemodeSpecialcomments:Thefrozendataoffiducial3GPPprotocolversion:2021/09.小区重选流程Reselectionprioritieshandling:1)AbsoluteprioritiesofdifferentE-UTRANfrequenciesorinter-RATfrequenciesmaybeprovidedtotheUEinthesysteminformation,intheRRCConnectionReleasemessage,orbyinheritingfromanotherRATatinter-RATcell(re)selection.2)Inthecaseofsysteminformation,anE-UTRANfrequencyorinter-RATfrequencymaybelistedwithoutprovidingapriority(i.e.thefieldcellReselectionPriorityisabsentforthatfrequency).Ifprioritiesareprovidedindedicatedsignalling,theUEshallignorealltheprioritiesprovidedinsysteminformation.3)IfUEisincampedonanycellstate,UEshallonlyapplytheprioritiesprovidedbysysteminformationfromcurrentcell,andtheUEpreservesprioritiesprovidedbydedicatedsignallingunlessspecifiedotherwise.4)WhentheUEincampednormallystate,hasonlydedicatedprioritiesotherthanforthecurrentfrequency,theUEshallconsiderthecurrentfrequencytobethelowestpriorityfrequency(i.e.lowerthantheeightnetworkconfiguredvalues).5)TheUEshalldeleteprioritiesprovidedbydedicatedsignallingwhen:-theUEentersRRC_CONNECTEDstate;or-theoptionalvaliditytimeofdedicatedpriorities(T320)expires;or-aPLMNselectionisperformedonrequestbyNAS.6)TheUEshallonlyperformcellreselectionevaluationforE-UTRANfrequenciesandinter-RATfrequenciesthataregiveninsysteminformationandforwhichtheUEhasapriorityprovided.7)TheUEshallnotconsideranyblacklistedcellsascandidateforcellreselection.8)TheUEshallinherittheprioritiesprovidedbydedicatedsignallingandtheremainingvaliditytime(i.e.,T320inE-UTRA,T322inUTRAandT3230,FFSinGERAN),ifconfigured,atinter-RATcell(re)selection.Reference:36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification;36.304:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);Equipment(UE)proceduresinidlemodeSpecialcomments:Thefrozendataoffiducial3GPPprotocolversion:2021/09.寻呼过程流程NetworkTriggedServiceRequest(Paging)procedure:IftheMMEneedstosignalwiththeUEthatisinECM-IDLEstate,e.g.toperformtheMME/HSS-initiateddetachprocedurefortheECM-IDLEmodeUEortheS GWreceivescontrolsignalling(e.g.CreateDedicatedBearerRequestorModifyDedicatedBearerRequest),theMMEstartsnetworktriggeredservicerequestprocedurefromstep3.IfISRisactivated,whentheServingGWreceivesaCreateDedicatedBearerRequestorModifyBearerRequestforaUE,andtheS GWdoesnothaveadownlinkS1-UandtheSGSNhasnotifiedtheServingGWthattheUEhasmovedtoPMM-IDLEorSTANDBYstate,theServingGWbufferssignallingmessagesandtriggersMMEandSGSNtopageUE.InthiscasetheS GWwillbenotifiedaboutthecurrentRATtypebasedontheUEtriggeredservicerequestprocedure.TheS GWwillgoonexecutingthededicatedbeareractivationordedicatedbearermodificationprocedure,i.e.sendthecorrespondingbufferedsignallingtoMMEorSGSNwhichUEresidesinnowandinformthecurrentRATtypetothePDNGWiftheRATtypehasbeenchangedcomparedtothelastreportedRATType.IfdynamicPCCisdeployed,thecurrentRATtypeinformationshallalsobeconveyedfromthePDNGWtothePCRF.IfthePCRFresponseleadstoanEPSbearermodificationthePDNGWshouldinitiateabearerupdateprocedureasspecifiedinclause5.4.2.1below.Reference:23.401:GeneralPacketRadioService(GPRS)enhancementsforEvolvedUniversalTerrestrialRadioAccessNetwork(E-UTRAN)access;36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification;36.413:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);S1ApplicationProtocol(S1AP).随机接入流程RandomAccessprocedure:Therandomaccessprocedureischaracterizedby:-CommonprocedureforFDDandTDD;-Oneprocedureirrespectiveofcellsize;Therandomaccessprocedureisperformedforthefollowingfiveevents:-InitialaccessfromRRC_IDLE;-RRCConnectionRe-establishmentprocedure;-Handover;-DLdataarrivalduringRRC_CONNECTEDrequiringrandomaccessprocedure;-E.g.whenULsynchronisationstatusis“non-synchronised;-ULdataarrivalduringRRC_CONNECTEDrequiringrandomaccessprocedure;-E.g.whenULsynchronisationstatusisnon-synchronisedortherearenoPUCCHresourcesforSRavailable.Furthermore,therandomaccessproceduretakestwodistinctforms:-Contentionbased(applicabletoallfiveevents);-Non-contentionbased(applicabletoonlyhandoverandDLdataarrival).NormalDL/ULtransmissioncantakeplaceaftertherandomaccessprocedure.Reference:36.300:EvolvedUniversalTerrestrialRadioAccess(E-UTRA)andEvolvedUniversalTerrestrialRadioAccessNetwork(E-UTRAN);Overalldescription;Stage2.ATTACH流程ATTACH流程E-UTRANInitialAttachprocedure:AUE/userneedstoregisterwiththenetworktoreceiveservicesthatrequireregistration.ThisregistrationisdescribedasNetworkAttachment.Thealways-onIPconnectivityforUE/usersoftheEPSisenabledbyestablishingadefaultEPSbearerduringNetworkAttachment.ThePCCrulesappliedtothedefaultEPSbearermaybepredefinedinthePDNGWandactivatedintheattachmentbythePDNGWitself.TheAttachproceduremaytriggeroneormultipleDedicatedBearerEstablishmentprocedurestoestablishdedicatedEPSbearer(s)forthatUE.Duringtheattachprocedure,theUEmayrequestforanIPaddressallocation.TerminalsutilisingonlyIETFbasedmechanismsforIPaddressallocationarealsosupported.DuringtheInitialAttachproceduretheMobileEquipmentIdentityisobtainedfromtheUE.TheMMEoperatormaychecktheMEIdentitywithanEIR.Atleastinroamingsituations,theMMEshouldpasstheMEIdentitytotheHSS,and,ifaPDNGWoutsideoftheVPLMN,shouldpasstheMEIdentitytothePDNGW.TheE-UTRANInitialAttachprocedureisusedforEmergencyAttachbyUEsthatneedtoperformemergencyservicesbutcannotgainnormalservicesfromthenetwork.TheseUEsareinlimitedservicestateasdefinedinTS23.12210.AlsoUEsthathadattachedfornormalservicesanddonothaveemergencybearersestablishedandarecampedonacellinlimitedservicestate(e.g.restrictedTrackingAreaornotallowedCSG)shallinitiatetheAttachproceduresindicatingthattheattachistoreceiveemergencyservices.UEsthatcampnormallyonacell,i.e.UEsthatarenotinlimitedservicestate,shouldinitiatenormalinitialattachwhennotalreadyattachedandshallinitiatetheUERequestedPDNConnectivityproceduretoreceiveemergencyEPSbearerservices.NOTE1:AUEthatisemergencyattachedperformsinitialattachprocedurebeforebeingabletoobtainnormalservices.Reference:23.401:GeneralPacketRadioService(GPRS)enhancementsforEvolvedUniversalTerrestrialRadioAccessNetwork(E-UTRAN)access;36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification;36.413:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);S1ApplicationProtocol(S1AP).TAU流程E-UTRANTrackingAreaUpdateprocedures:TheprocedureisinitiatedbyanUEineitherECM-IDLEstateorECM-CONNECTEDstate.NOTE1:Ifthetrackingareaupdateprocedurefailsamaximumallowablenumberoftimes,oriftheMMEreturnsaTrackingAreaUpdateReject(Cause)message,theUEshallenterEMMDEREGISTEREDstate.IftheUpdateLocationAckmessageindicatesareject,thisshouldbeindicatedtotheUE,andtheUEshallnotaccessnon-PSservicesuntilasuccessfullocationupdateisperformed.Reference:23.401:GeneralPacketRadioService(GPRS)enhancementsforEvolvedUniversalTerrestrialRadioAccessNetwork(E-UTRAN)access;36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification;36.413:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);S1ApplicationProtocol(S1AP).DETACH流程UE-initiatedDetachprocedureforE-UTRAN:TheDetachprocedureisthatUEcampsonE-UTRANandDetachRequestissenttoMME.Reference:23.401:GeneralPacketRadioService(GPRS)enhancementsforEvolvedUniversalTerrestrialRadioAccessNetwork(E-UTRAN)access;36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification;36.413:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);S1ApplicationProtocol(S1AP).鉴权流程鉴权流程E-UTRANAuthenticationandKeyAgreementprocedure:EPSAKAistheauthenticationandkeyagreementprocedurethatshallbeusedoverE-UTRAN,betweentheUEandMME.EPSAKAisspecifiedinTS33.40141.EPSAKAshallproducekeyingmaterialformingabasisforuserplane(UP),RRC,andNAScipheringkeysaswellasRRCandNASintegrityprotectionkeys.Reference:23.401:GeneralPacketRadioService(GPRS)enhancementsforEvolvedUniversalTerrestrialRadioAccessNetwork(E-UTRAN)access;33.401:3GPPSystemArchitectureEvolution(SAE);Securityarchitecture.36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification;36.413:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);S1ApplicationProtocol(S1AP).UE呼叫流程Reference:23.401:GeneralPacketRadioService(GPRS)enhancementsforEvolvedUniversalTerrestrialRadioAccessNetwork(E-UTRAN)access;36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification;36.413:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);S1ApplicationProtocol(S1AP).遨游用户效力过程E-UTRANRoamingprocedure:IntheroamingscenariothevPLMNoperatesGn/Gp2Gand/or3GSGSNsaswellasMMEandS GWforE-UTRANaccess.ThehPLMNoperatesaP GW.RoamingandinteraccessmobilitybetweenGn/Gp2Gand/or3GSGSNsandanMME/S GWareenabledby:-GnfunctionalityasspecifiedbetweentwoGn/GpSGSNs,whichisprovidedbytheMME,and-GpfunctionalityasspecifiedbetweenGn/GpSGSNandGn/GpGGSNthatisprovidedbytheP GW.AllthisGpandGnfunctionalitybasesonGTPversion1only.ForroamingsubscriberstheMMEmayalternativelychoosetheRFSPIndexinusebasedonthevisitednetworkpolicy(e.g.,anRFSPIndexvaluepre-configuredperHPLMN,orasingleRFSPIndexvaluetobeusedforallroamersindependentoftheHPLMN).Reference:23.401:GeneralPacketRadioService(GPRS)enhancementsforEvolvedUniversalTerrestrialRadioAccessNetwork(E-UTRAN)access;36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification;36.413:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);S1ApplicationProtocol(S1AP).UE上下文修正流程HSStoupdatetheHSSuserprofilestoredintheMME.WhenevertheHSSuserprofileischangedforauserintheHSS,andthechangesaffecttheHSSuserprofilestoredintheMME,theMMEshallbeinformed.TheMMEbuildsaSessionManagementRequestincludingthePTI,EPSBearerQoSparameters(excludingARP),TFT,APNAMBRandEPSBearerIdentity.HSStoupdatetheHSSuserprofilestoredintheMME.WhenevertheHSSuserprofileischangedforauserintheHSS,andthechangesaffecttheHSSuserprofilestoredintheMME,theMMEshallbeinformed.IftheQCIand/orARPand/orsubscribedAPN-AMBRhasbeenmodifiedandthereisrelatedactivePDNconnectionwiththemodifiedQoSProfiletheMMEsendstheModifyBearerCommand(EPSBearerIdentity,EPSBearerQoS,APNAMBR)messagetotheServingGW.TheEPSBearerIdentityidentifiesthedefaultbeareroftheaffectedPDNconnection.TheEPSBearerQoScontainstheEPSsubscribedQoSprofiletobeupdated.TheServingGWsendstheModifyBearerCommand(EPSBearerIdentity,EPSBearerQoS,APNAMBR)messagetothePDNGWIftheQCIand/orARPparameter(s)havebeenmodified,TheServingGWsendstheUpdateBearerRequest(PTI,EPSBearerIdentity,EPSBearerQoS,TFT,APNAMBR)messagetotheMMETheMMEbuildsaSessionManagementRequestincludingthePTI,EPSBearerQoSparameters(excludingARP),TFT,APNAMBRandEPSBearerIdentity.UE上下文修正流程续HSStoupdatetheHSSuserprofilestoredintheMME.WhenevertheHSSuserprofileischangedforauserintheHSS,andthechangesaffecttheHSSuserprofilestoredintheMME,theMMEshallbeinformed.IfneithertheQCInortheARPhavebeenmodified,butinsteadonlytheAPN-AMBRwasupdated,TheMMEbuildsaSessionManagementRequestmessageincludingtheTFT,APN-AMBRandEPSBearerIdentity.TheMMEthensendsaDownlinkNASTransport(SessionManagementConfiguration)messagetotheeNodeB.IftheAPNAMBRhaschanged,theMMEmayalsoupdatetheUEAMBR.TheeNodeBsendstheDirectTransfer(SessionManagementRequest)messagetotheUE.TheUEusestheuplinkpacketfilter(ULTFT)todeterminethemappingoftrafficflowstotheradiobearer.TheUEstoresthemodifiedAPN-AMBRvalue.TheUEshallsetitsTINtoGUTIifthemodifiedEPSbearerwasestablishedbeforeISRactivation.TheUENASlayerbuildsaSessionManagementResponseincludingEPSBearerIdentity.TheUEthensendsaDirectTransfer(SessionManagementResponse)messagetotheeNodeB.UE上下文释放流程TheHSS-InitiatedDetachprocedureisinitiatedbytheHSS.TheHSSusesthisprocedureforoperator-determinedpurposestorequesttheremovalofasubscribersMMandEPSbearerattheMMEandalsoattheSGSNifbothanMMEandanSGSNareregisteredintheHSS.IftheHSSwantstorequesttheimmediatedeletionofasubscribersMMcontextsandEPSBearers,theHSSshallsendaCancelLocation(IMSI,CancellationType)messagewithCancellationTypesettoSubscriptionWithdrawntotheregisteredMMEandalsototheSGSNifanSGSNisalsoregistered.TheUEwillreceiveonlyoneDetachRequestmessageintheRATwhereitcurrentlycampsonIftheMMEhasanactiveUEcontext,theMMEsendsaDeleteSessionRequest(TEID)messagetotheServingGWtodeactivatetheEPSBearerContextinformationintheServingGW.WhentheSGWreceivesthefirstDeleteSessionRequestmessagefromtheMMEorSGSNinISRactivatedstate,theServingGWdeactivatesISR,releasestherelatedEPSBearercontextinformationandrespondswithDeleteSessionResponseAfterreceivingtheDetachAcceptmessage,theMMEreleasestheS1-MMEsignallingconnectionfortheUEbysendingS1ReleaseCommand(Cause)messagetotheeNodeBwithCausesettoDetach.ThedetailsofthissteparecoveredintheS1ReleaseProcedure,TheUEsendsNASmessageDetachRequest(GUTI,SwitchOff)totheMME.ThisNASmessageisusedtotriggertheestablishmentoftheS1connectioniftheUEwasinECM-IDLEmode.SwitchOffindicateswhetherdetachisduetoaswitchoffsituationornot.TheeNodeBforwardsthisNASmessagetotheMMEalongwiththeTAI+ECGIofthecellwhichtheUEisusing.UE上下文释放流程续TheMMEinitiateddetachprocedureiseitherexplicit(e.g.byO&Mintervention)orimplicit.TheMMEmayimplicitlydetachaUE,ifithasnothadcommunicationwithUEforalongperiodoftime.TheMMEdoesnotsendtheDetachRequest(DetachType)messagetotheUEforimplicitdetach.TheimplicitdetachislocaltotheMME,i.e.anSGSNregistrationwillnotbedetached.IftheUEisinECM-CONNNECTEDstatetheMMEmayexplicitlydetachtheUEbysendingaDetachRequestmessagetotheUE.TheDetachTypemaybesettore-attachinwhichcasetheUEshouldre-attachattheendofthedetachprocess.IftheUEisinECM-IDLEstatetheMMEpagestheUE.AnyEPSBearerContextinformationintheServingGWregardingthisparticularUEandrelatedtotheMMEaredeactivatedbytheMMEsendingDeleteSessionRequest(TEID)messagetotheServingGW.IfthePDNGWrequestedUEslocationinfo,theMMEalsoincludestheUserLocationInformationIEinthismessage.WhentheSGWreceivesthefirstDeleteSessionRequestmessagefromtheMMEorSGSNinISRactivatedstate,theServingGWdeactivatesISR,releasestherelatedEPSBearercontextinformationandrespondswithDeleteSessionResponse(TEID).WhentheSGWreceivestheDeleteSessionRequestmessagefromtheMMEorSGSNinISRdeactivatedstate,theServingGWreleasestherelatedEPSBearercontextinformationandjumpstostep6bysendingaDeleteSessionRequest(TEID)messagetothePDNGW.Afterstep7theServingGWrespondsbacktotheMME/SGSNwiththeDeleteSessionResponse(TEID)message.IftheUEreceivestheDetachRequestmessagefromtheMMEinthestep1,theUEsendsaDetachAcceptmessagetotheMMEanytimeafterstep1.TheeNodeBforwardsthisNASmessagetotheMMEalongwiththeTAI+ECGIofthecellwhichtheUEisusing.AfterreceivingtheDetachAcceptmessage,DeleteSessionResponseand,ifappropriate,DetachAcknowledgemessage,theMMEreleasestheS1-MMEsignallingconnectionfortheUEbysendinganS1ReleaseCommand(Cause)messagetotheeNodeB.ThedetailsofthissteparecoveredintheS1ReleaseProcedure,asdescribedinclause5.3.5bystep4tostep6.IftheDetachTyperequeststheUEtomakeanewattach,theUEreattachesaftertheRRCConnectionReleaseiscompleted.E-RAB建立流程IfdynamicPCCisdeployed,thePCRFsendsaPCCdecisionprovision(QoSpolicy)messagetothePDNGW.ThiscorrespondstotheinitialstepsofthePCRF-InitiatedIPCANSessionModificationprocedureortothePCRFresponseinthePCEFinitiatedIP-CANSessionModificationprocedureasdefinedinTS23.2036,uptothepointthatthePDNGWrequestsIPCANBearerSignalling.IfdynamicPCCisnotdeployed,thePDNGWmayapplylocalQoSpolicy.TheServingGWsendstheCreateBearerRequest(IMSI,PTI,EPSBearerQoS,TFT,S1-TEID,LBI,ProtocolConfigurationOptions)messagetotheMME.TheMMEselectsanEPSBearerIdentity,whichhasnotyetbeenassignedtotheUE.TheMMEthenbuildsaSessionManagementRequestincludingthePTI,TFT,EPSBearerQoSparameters(excludingARP),ProtocolConfigurationOptions,theEPSBearerIdentityandtheLinkedEPSBearerIdentity(LBI).IftheUEhasUTRANorGERANcapabilities,theMMEusestheEPSbearerQoSparameterstoderivethecorrespondingPDPcontextparametersQoSNegotiated(R99QoSprofile),RadioPriority,PacketFlowIdandTIandincludesthemintheSessionManagementRequest.IftheUEindicatedintheUENetworkCapabilityitdoesnotsupportBSSpacketflowprocedures,thentheMMEshallnotincludethePacketFlowId.TheMMEthensignalstheBearerSetupRequest(EPSBearerIdentity,EPSBearerQoS,SessionManagementRequest,S1-TEID)messagetotheeNodeB.TheeNodeBmapstheEPSBearerQoStotheRadioBearerQoS.ItthensignalsaRRCConnectionReconfiguration(RadioBearerQoS,SessionManagementRequest,EPSRBIdentity)messagetotheUE.TheUEshallstoretheQoSNegotiated,RadioPriority,PacketFlowIdandTI,whichitreceivedintheSessionManagementRequest,forusewhenaccessingviaGERANorUTRAN.TheUENASstorestheEPSBearerIdentityandlinksthededicatedbearertothedefaultbearerindicatedbytheLinkedEPSBearerIdentity(LBI).TheUEusestheuplinkpacketfilter(ULTFT)todeterminethemappingoftrafficflowstotheradiobearer.TheUEmayprovidetheEPSBearerQoSparameterstotheapplicationhandlingthetrafficflow.TheapplicationusageoftheEPSBearerQoSisimplementationdependent.TheUEshallnotrejecttheRRCConnectionReconfigurationonthebasisoftheEPSBearerQoSparameterscontainedintheSessionManagementRequest.TheUENASlayerbuildsaSessionManagementResponseincludingEPSBearerIdentity.TheUEthensendsaDirectTransfer(SessionManagementResponse)messagetotheeNodeB.E-RAB建立流程ThepurposeoftheUErequestedbearerresourceallocationprocedureisforaUEtorequestanallocationofbearerresourcesforatrafficflowaggregate.TheUErequestsaspecificQoSdemand(QCI)andoptionallysendsaGBRrequirementforanewtrafficflowaggregate.Ifacceptedbythenetwork,thisprocedureinvokesadedicatedEPSbearercontextactivationprocedure(seesubclause6.4.2)oranEPSbearercontextmodificationprocedure(seesubclause6.4.3).Inordertorequesttheallocationofbearerresourcesforonetrafficflowaggregate,theUEshallsendaBEARERRESOURCEALLOCATIONREQUESTmessagetotheMME,starttimerT3480andenterthestatePROCEDURETRANSACTIONPENDINGUponreceiptoftheBEARERRESOURCEALLOCATIONREQUESTmessage,theMMEcheckswhethertheresourcesrequestedbytheUEcanbeestablishedbyverifyingtheEPSbeareridentitygivenintheLinkedEPSbeareridentityIEtobeanyoftheactivedefaultEPSbearercontext(s).Ifthebearerresourceallocationrequestedisacceptedbythenetwork,theMMEshallinitiateeitheradedicatedEPSbearercontextactivationprocedureoranEPSbearercontextmodificationprocedure.E-RAB释放流程RadiobearersfortheUEintheECM-CONNECTEDstatemaybereleasedduetolocalreasons(e.g.abnormalresourcelimitationorradioconditionsdonotallowtheeNodeBtomaintainalltheallocatedGBRbearers:itisnotexpectedthatnon-GBRbearersarereleasedbytheeNodeBunlesscausedbyerrorsituations).TheUEdeletesthebearercontextsrelatedtothereleasedradiobearers.WhentheeNodeBreleasesradiobearersinstep0,itsendsanindicationofbearerreleasetotheMME.Thisindicationmaybee.g.theBearerReleaseRequest(EPSBearerIdentity)messagetotheMME,oralternativelyInitialContextSetupComplete,HandoverRequestAckandUEContextResponse,PathSwitchRequestmayalsoindicatethereleaseofabearer.TheMMEsendstheDeleteBearerCommand(EPSBearerIdentity)messagetotheServingGWtodeactivatetheselecteddedicatedbearer.TheServingGWsendstheDeleteBearerRequest(EPSBearerIdentity)messagetotheMME.TheMMEdeletesthebearercontextsrelatedtothedeactivatedEPSbearerandacknowledgesthebearerdeactivationtotheServingGWbysendingaDeleteBearerResponse(EPSBearerIdentity)message.ThepurposeoftheUErequestedPDNdisconnectionprocedureisforaUEtorequestdisconnectionfromonePDN.TheUEcaninitiatethisproceduretodisconnectfromanyPDNaslongasitisconnectedtoatleastoneotherPDN.Withthisprocedure,allEPSbearercontextsestablishedtowardsthisPDN,includingthedefaultEPSbearercontext,arereleased.E-RAB修正流程TheUErequestedbearerresourcemodificationprocedureforanE-UTRANallowstheUEtorequestforamodificationofbearerresources(e.g.allocationorreleaseofresources)foronetrafficflowaggregatewithaspecificQoSdemand.Alternatively,theprocedureallowstheUEtorequestforthemodificationofthepacketfiltersusedforanactivetrafficflowaggregate,withoutchangingQoS.Ifacceptedbythenetwork,therequestinvokeseithertheDedicatedBearerActivationProcedure,theBearerModificationProcedureoradedicatedbearerisdeactivatedusingthePDNGWInitiatedBearerDeactivationProcedure.TheprocedureisusedbytheUEwhentheUEalreadyhasaPDNconnectionwiththePDNGW.AUEcansendasubsequentRequestBearerResourceModificationMessagebeforethepreviousprocedureiscompleted.RRC重建流程RRCConnectionEstablishmentprocedure:Thepurposeofthisprocedureistore-establishtheRRCconnection,whichinvolvestheresumptionofSRB1operationandthere-activationofsecurity.AUEinRRC_CONNECTED,forwhichsecurityhasbeenactivated,mayinitiatetheprocedureinordertocontinuetheRRCconnection.Theconnectionre-establishmentsucceedsonlyiftheconcernedcellispreparedi.e.hasavalidUEcontext.IncaseE-UTRANacceptsthere-establishment,SRB1operationresumeswhiletheoperationofotherradiobearersremainssuspended.IfASsecurityhasnotbeenactivated,theUEdoesnotinitiatetheprocedurebutinsteadmovestoRRC_IDLEdirectly.E-UTRANappliestheprocedureasfollows:-toreconfigureSRB1andtoresumedatatransferonlyforthisRB;-tore-activateASsecuritywithoutchangingalgorithms.ThefirstRRCConnectionReconfigurationmessageisusedtoresumeSRB2andallDRBsthataresuspendedaftersuccessfulcompletionoftheRRCConnectionRe-establishmentprocedure.Reference:36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification.Special comments: The frozen date of fiducial 3GPP protocol version : 2021/09.RRC重建到目的小区流程RRCConnectionRe-establishmentCrossInter-eNBHandoverprocedure:IncaseofInter-eNBhandoverwithinE-UTRA,WhentherearetheUEcontextinthetargeteNB.TheUEmaybeinitiatetheRRCconnectionre-establishmentprocedureduetohandoverfailure,andthecurrentcellisthehandovertargetcellorothercellsundercontrolofthetargeteNB.TheInter-eNBhandoverprocedurecontinueexecuteaftersuccessfulcompletionoftheRRCConnectionRe-establishmentprocedure.Reference:36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification.小区内切换流程Intra-CellHandoverprocedure:Anintra-cellhandoverproceduremaybeusedtochangethekeysinRRC_CONNECTED.Theprocedureisperformedforthefollowingcase:-IfASKeys(KUPenc,KRRCintandKRRCenc)needtobechangedinRRC_CONNECTED,anintra-cellhandovershallbeused.-E.g.1:MMEtriggersanintracellhandoverbecauseKeNBrefreshperiodically.-E.g.2:ForX2-handoverprocedure,ThetargeteNBcanimmediatelyinitiateanintra-cellhandovertotakethenewNHintouseoncethenewNHhasarrivedintheS1PATHSWITCHREQUESTACKNOWLEDGE.-Anintra-cellhandoverprocedureshallbeinitiatedbytheeNBwhenaPDCPCOUNTsisabouttobere-usedwiththesameRadioBeareridentityandwiththesameKeNB,andtheKeNBisre-freshedw.r.t.theRRCandUPCOUNTaftertheprocedure.Reference:23.401:GeneralPacketRadioService(GPRS)enhancementsforEvolvedUniversalTerrestrialRadioAccessNetwork(E-UTRAN)access;33.401:3GPPSystemArchitectureEvolution(SAE);Securityarchitecture;36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification.eNodeB内切换流程Inter-CellHandoverprocedure:TheprocedureisusedtohandoveraUEfromasourcecelltoatargetcellinthesameeNodeB.IntheproceduretheMMEandtheeNodeBisunchanged,anditisnotrequiredtochangetheASsecurityalgorithmduringintra-eNBhandover.Reference:23.401:GeneralPacketRadioService(GPRS)enhancementsforEvolvedUniversalTerrestrialRadioAccessNetwork(E-UTRAN)access;33.401:3GPPSystemArchitectureEvolution(SAE);Securityarchitecture;36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification;36.423:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);X2applicationprotocol(X2AP);36.413:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);S1ApplicationProtocol(S1AP).eNodeB间S1接口切换流程eNodeB间S1接口切换流程S1-basedhandoverprocedure:TheS1-basedhandoverprocedureisusedwhentheX2-basedhandovercannotbeused.ThesourceeNodeBinitiatesahandoverbysendingHandoverRequiredmessageovertheS1-MMEreferencepoint.ThisproceduremayrelocatetheMMEand/ortheServingGW.ThesourceMMEselectsthetargetMME.TheMMEshouldnotberelocatedduringinter-eNodeBhandoverunlesstheUEleavestheMMEPoolAreawheretheUEisserved.TheMME(targetMMEforMMErelocation)determinesiftheServingGWneedstoberelocated.IftheServingGWneedstoberelocatedtheMMEselectsthetargetServingGW.ThesourceeNodeBdecideswhichoftheEPSbearersaresubjectforforwardingofpacketsfromthesourceeNodeBtothetargeteNodeB.TheEPCdoesnotchangethedecisionstakenbytheRANnode.PacketforwardingcantakeplaceeitherdirectlyfromthesourceeNodeBtothetargeteNodeB,orindirectlyfromthesourceeNodeBtothetargeteNodeBviathesourceandtargetServingGWs(oriftheServingGWisnotrelocated,onlythesingleServingGW).TheavailabilityofadirectforwardingpathisdeterminedinthesourceeNodeBandindicatedtothesourceMME.IfX2connectivityisavailablebetweenthesourceandtargeteNodeBs,adirectforwardingpathisavailable.Ifadirectforwardingpathisnotavailable,indirectforwardingmaybeused.ThesourceMMEusestheindicationfromthesourceeNodeBtodeterminewhethertoapplyindirectforwarding.ThesourceMMEindicatestothetargetMMEwhetherindirectforwardingshouldapply.Basedonthisindication,thetargetMMEdetermineswhetheritappliesindirectforwarding.Reference:23.401:GeneralPacketRadioService(GPRS)enhancementsforEvolvedUniversalTerrestrialRadioAccessNetwork(E-UTRAN)access;36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification;36.413:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);S1ApplicationProtocol(S1AP).eNodeB间X2接口切换流程X2-basedhandoverwithServingGWrelocationprocedure:TheprocedureisusedtohandoveraUEfromasourceeNodeBtoatargeteNodeBusingtheX2referencepoint.IntheproceduretheMMEisunchanged.InadditiontotheX2referencepointbetweenthesourceandtargeteNodeB,theproceduresrelyonthepresenceofS1-MMEreferencepointbetweentheMMEandthesourceeNodeBaswellasbetweentheMMEandthetargeteNodeB.ThehandoverpreparationandexecutionphasesareperformedasspecifiedinTS36.3005.IfemergencybearerservicesareongoingfortheUEhandovertothetargeteNodeBisperformedindependentoftheHandoverRestrictionList.TheMMEchecks,aspartoftheTrackingAreaUpdateintheexecutionphase,ifthehandoveristoarestrictedareaandifsoMMEreleasesthenon-emergencybearers.WhentheUEreceivesthehandovercommanditwillremoveanyEPSbearersforwhichitdidnotreceivethecorrespondingEPSradiobearersinthetargetcell.Aspartofhandoverexecution,downlinkpacketsareforwardedfromthesourceeNodeBtothetargeteNodeB.WhentheUEhasarrivedtothetargeteNodeB,downlinkdataforwardedfromthesourceeNodeBcanbesenttoit.UplinkdatafromtheUEcanbedeliveredviathe(source)ServingGWtothePDNGW.OnlythehandovercompletionphaseisaffectedbyapotentialchangeoftheServingGW,thehandoverpreparationandexecutionphasesareidentical.IftheMMEreceivesarejectiontoaNASprocedure(e.g.dedicatedbearerestablishment/modification/release;locationreportingcontrol;NASmessagetransfer;etc.)fromtheeNodeBwithanindicationthatanX2handoverisinprogress(seeTS36.3005),theMMEshallreattemptthesameNASprocedureeitherwhenthehandoveriscompleteorthehandoverisdeemedtohavefailed.ThefailureisknownbyexpiryofthetimerguardingtheNASprocedure.Reference:23.401:GeneralPacketRadioService(GPRS)enhancementsforEvolvedUniversalTerrestrialRadioAccessNetwork(E-UTRAN)access;36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification;36.423:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);X2applicationprotocol(X2AP).LTE2UTRAN切换流程LTE2UTRAN切换流程UTRANS2LTE切换流程UTRANS2LTE切换流程LTE2GERAN切换流程LTE2GERAN切换流程GERAN2LTE切换流程GERAN2LTE切换流程LTE2CDMA切换流程优化LTE2CDMA切换流程优化CDMA2LTE切换流程优化LTE2CDMA切换流程非优化CDMA2LTE切换流程非优化CSFB流程PSHOE-UTRANToGSM/UMTSCSFBprocedureMobileTerminatingcallinactivemodeWithPSHO:TheCSfallbackinEPSenablestheprovisioningofvoiceandotherCS-domainservices(e.g.CSUDIvideo/SMS/LCS/USSD)byreuseofCSinfrastructurewhentheUEisservedbyE UTRAN.ACSfallbackenabledterminal,connectedtoE UTRANmayuseGERANorUTRANtoconnecttotheCS domain.ThisfunctionisonlyavailableincaseE UTRANcoverageisoverlappedbyeitherGERANcoverageorUTRANcoverage.CSFallbackandIMS basedservicesshallbeabletoco-existinthesameoperatorsnetwork.Reference:23.401:GeneralPacketRadioService(GPRS)enhancementsforEvolvedUniversalTerrestrialRadioAccessNetwork(E-UTRAN)access;23.272:3rdGenerationPartnershipProject;TechnicalSpecificationGroupServicesandSystemAspects;CircuitSwitchedFallbackinEvolvedPacketSystem;36.413:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);S1ApplicationProtocol(S1AP).CSFB流程non-PSHOE-UTRANToGSM/UMTSCSFBprocedureMobileTerminatingcallinactivemodeNoPSHO:TheCSfallbackinEPSenablestheprovisioningofvoiceandotherCS-domainservices(e.g.CSUDIvideo/SMS/LCS/USSD)byreuseofCSinfrastructurewhentheUEisservedbyE UTRAN.ACSfallbackenabledterminal,connectedtoE UTRANmayuseGERANorUTRANtoconnecttotheCS domain.ThisfunctionisonlyavailableincaseE UTRANcoverageisoverlappedbyeitherGERANcoverageorUTRANcoverage.CSFallbackandIMS basedservicesshallbeabletoco-existinthesameoperatorsnetwork.Reference:23.401:GeneralPacketRadioService(GPRS)enhancementsforEvolvedUniversalTerrestrialRadioAccessNetwork(E-UTRAN)access;23.272:3rdGenerationPartnershipProject;TechnicalSpecificationGroupServicesandSystemAspects;CircuitSwitchedFallbackinEvolvedPacketSystem;36.413:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);S1ApplicationProtocol(S1AP).CSFB流程IDLEE-UTRANToGSM/UMTSCSFBprocedureMobileTerminatingcallinidlemode:TheCSfallbackinEPSenablestheprovisioningofvoiceandotherCS-domainservices(e.g.CSUDIvideo/SMS/LCS/USSD)byreuseofCSinfrastructurewhentheUEisservedbyE UTRAN.ACSfallbackenabledterminal,connectedtoE UTRANmayuseGERANorUTRANtoconnecttotheCS domain.ThisfunctionisonlyavailableincaseE UTRANcoverageisoverlappedbyeitherGERANcoverageorUTRANcoverage.CSFallbackandIMS basedservicesshallbeabletoco-existinthesameoperatorsnetwork.Reference:23.401:GeneralPacketRadioService(GPRS)enhancementsforEvolvedUniversalTerrestrialRadioAccessNetwork(E-UTRAN)access;23.272:3rdGenerationPartnershipProject;TechnicalSpecificationGroupServicesandSystemAspects;CircuitSwitchedFallbackinEvolvedPacketSystem;36.413:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);S1ApplicationProtocol(S1AP).SRVCC流程CDMAE-UTRANToCDMA1XRTTSRVCCprocedure:ForSRVCC-capableUEs,thecallisalwaysanchoredattheVCCASinthe3GPP2sIMS.The3GPP21xCSIWSenablesasingleradioUEtocommunicateinparallelbothwiththesourcesystemandthetargetsystem.FromVCCperspective,thismechanismminimizesthevoicegapbysupportingthetransportofsignallingforestablishmentofthetargetCSaccesslegwhiletheterminalisconnectedtothesourcePSaccessnetwork.Reference:23.401:GeneralPacketRadioService(GPRS)enhancementsforEvolvedUniversalTerrestrialRadioAccessNetwork(E-UTRAN)access;23.216:3rdGenerationPartnershipProject;TechnicalSpecificationGroupServicesandSystemAspects;SingleRadioVoiceCallContinuity(SRVCC)36.413:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);S1ApplicationProtocol(S1AP).SRVCC流程GERAN/UMTSE-UTRANToGERAN/UMTSSRVCCprocedure:ForSRVCCfromE UTRANtoUTRAN/GERAN,MMEfirstreceivesthehandoverrequestfromE UTRANwiththeindicationthatthisisforSRVCChandling,andthentriggerstheSRVCCprocedurewiththeMSCServerenhancedwithSRVCCviatheSvreferencepointifMMEhasSRVCCSTN-SRinformationforthisUE.MSCServerenhancedforSRVCCtheninitiatesthesessiontransferproceduretoIMSandcoordinatesitwiththeCShandoverproceduretothetargetcell.MSCServerenhancedforSRVCCthensendsPS-CShandoverResponsetoMME,whichincludesthenecessaryCSHOcommandinformationfortheUEtoaccesstheUTRAN/GERAN.Reference:23.401:GeneralPacketRadioService(GPRS)enhancementsforEvolvedUniversalTerrestrialRadioAccessNetwork(E-UTRAN)access;23.216:3rdGenerationPartnershipProject;TechnicalSpecificationGroupServicesandSystemAspects;SingleRadioVoiceCallContinuity(SRVCC)36.413:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);S1ApplicationProtocol(S1AP).闭环功控流程1.ToupdateservingcellIBLERtargetaccordingtoOImessagefromneighbourcellsastoreduceinter-cellinterference.ThenewcellIBLERtargetwillbeconfigurednewUE.2.TosetTPCcommandbasedonIBLERmeasurementvalueandIBLERtargetvalue,astoassureexpectedIBLERleverl1.TosetTPCcommandbasedonSINRmeasurementvalueandSINRtargetvalue,astoassureexpectedSINRleverl.TheSINRtargetvalueisupdatedaccordingtoouter-looppowercontrol.SINRmeasurementvaluediffersinDMRS/SRSmeasurement.闭环功控流程1.ToupdateservingUESINRtargetaccordingtoOImessagefromneighbourcellsorpowerheadroom,astoadaptetothediversechannelconditionandinter-cellinterference.2.ToupdateandconfigNMAXvaluetoUEaccordingtoRBLERmeasurement.,astosaveRRCresource.GAP丈量配置流程GAPMeasurementprocedure:1.UeSendMeasmentReporttoeNodebtoindicateA2eventtrigged2.eNodeBJudgetheservingcellssignalbecomesbadandneedtotrigeInter-FreqorInter-RatMeasment(thereshouldbeInter-FreqInfoorInter-RatFreqInfooftheservingcell)3.eNodeBsendRRCConnectionReconfigurationtoUE,whichcontaintheGapconfigandA4orB1Measmentconfig4.UEsendRRCConnectionReconfigurationCompletetoeNodeB,whichmeansGapconfigandA4orB1measmentconfigissuccessReference:36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification,5.5.2.9MeasurementgapconfigurationANR丈量配置流程ANRMeasurementprocedure:1.UeSendMeasmentReporttoeNodeBtoindicateA3orA4eventtrigged,andstrongestPCIisunknown(eg.thePCIbelongstoanothereNodeb)2.eNodeBsendanewMeasmenttocommandUEtoreporttheCGIoftheunknownPCI,andalongDRXcyclemaybeneededforUEtoreadtheNCELLsSYSINFO3.UEreadstheNCELLsSIB1togettheNCELLsCGIandreportsittoeNodeb4.SRCeNodebsendRRCConnectionReconfigurationwhichcontainsHOcommandtoUE5.UErandomaccesstotheTareNodeb6.TareNodebmaysendnewMeasmentrequiretostoptheoldCGImeasmentReference:36.331:EvolvedUniversalTerrestrialRadioAccess(E-UTRA);RadioResourceControl(RRC);Protocolspecification,5.5.4Measurementreporttriggering