5G移動(dòng)通信-無線架構(gòu)-RAPP-CoDe-RAN-Architecture

5GforpeopleandthingsKeytotheprogrammableworldHOMEi5GRANArchitectureOverviewFebruary25th,2016MaindriversandusecasesKeyconceptsOverallarchitectureUser-andcontrol-planearchitectureLTE-5Gandmulti-RATintegrationMulti-connectivityoptionsMobilityconceptsOutlineMaindriversandusecases5Gforpeopleandthings–diversityofusecasesandrequirements10years

onbattery10-10010000<1msM2M100Mbps>10Gbpsavg.goodputUltrareliabilityultralowcostxmoredevicespeakdataratesxmoretrafficlatency3Dvideo/

4KscreensSensorNWAutonomousdrivingThroughput#ofDevices

|Cost|PowerRemotecontrol

ofrobotLatency|ReliabilityVRgamingCapacityfor

everyoneMissioncritical

broadcastWorkin

thecloudSmartcity

camerasIndustry4.0Flexibility

forthe

unknownExtreme

MobileBroadbandCriticalmachinetypecommunicationMassivemachinetypecommunicationSomepushforcentralization,otherfordistributionDiversityofRequirementsSeveral100MHzspectrumNewspectrumFrontandbackhaulrequirementshowseparateentitiesneedtocollaborate(eCoMP,dualconnectivity,etc.)CoordinationamongsmallcellsandwithmacroReduce

latencyto

millisecondsInstantresponseShorterTTIandShorterTTIandfunctionalities“inthebox”growbeyondbasiceNBfunctionality(e.g.corefunctions,…)Multi-CellcoordinationAtL1orhigherlayersHetNet,UltraDenseNetworkHigh#ofSmallCellsdistributiondistributioncentralizationcentralizationMobileNetworkTopologyLargerEuropeanoperatormacromacropre-aggregationsmallcellssmallcellsmacrox10.000

macrositesx100.000

smallcellsx1.000

pre-aggregation

sitescentral

gatewaysCNfunctionsx100aggregationsitesx10central

gatewaysaggregationsiteInternetOperatorservicesedgecloudedgecloudstarchaintreeInternetring= potentialsitefordatacenter

/aggregation/localbreakoutpointRRHsDiversex-haul,networktopologies,aggregationscenariosmacroDistanceandlatencytoradioaccessincreasesLocalbreakout

andfunctions5GCorenetworkLTE5GLTE5GLTE5G5GanchoredinLTE

(LTE-5GDualConnectivity)5GandLTEstand-aloneLTEanchoredin5G

(5G-LTEMulti-Connectivity)5G5Gwithmulti-hop

self-backhaul5GRANcloudvirtualizedhardware5GwithD2Dand

localswitching5GMECLocalGWRANfunctionsLTEairinterface5GairinterfaceFronthaulinterfaceRAN-CNinterfaceSelf-backhaulinterfaceRANinterfaceDevicetodeviceSensor/IoTdeviceOverallviewKeyconceptsandobjectives5GRadioArchitectureandnetworkdesignprinciplesFlexibilityandscalabilityoffunctions:C/UPlane,Cell/UErelatedLoad-adaptivescalingCentralizedarchitectureallowsbetterviewtotakebetterdecision(e.g.centralscheduler,trafficsteering)diversedeploymentscenariosdependingonavailablexhaulOptimizationofcontrolplaneanduserplaneentitiesElasticityAnyxhaulIntegratedControlMulticonnectivityLeanfunctionalarchitectureLTE5GUEUplaneCplane5G5GUEcmWmmWObjectivesTop-4Objectives

5GCommonArchitectureDesigncmW,mmW,WAcommonhigherlayerarchitectureandprotocolstacks.Consideringmulti-layerandIRAT:5G,LTE,WiFi,LAA

Multi-connectivitybydesign

RANarchitecturaloptionsforspotty5Gcoverageandmulti-connectivityusecases.Supportforcentralanddistributedfunctions.Supportforhighthroughputandrobustnessusecases.

NativeCloudRANDesigninterfacesandprotocolstacktoallowflexiblefunctionalsplitacc.toFronthaulanddatacentercapabilities.SupportCloudimplementation,scaling,anddynamicresourceallocation.Cloud-friendlyprotocoldesign.Networkflexibility

Supportnetworkslicing,andfunctionalallocationacc.toend-to-endservices.ConsiderSDNapproachesbydesignwithc-planeandu-planeseparationandacc.interfacesScenarios

5Gonly:WA,cmW,mmWInter-RAT:5G+LTE+WiFi+LAAanyxhaulDeploymentstudiesSpectrumFocusisbothlicensed(andnon-shared)andnonlicensed(WiFi)spectrumcases.Keyconcept:NetworkConvergenceSublayerSinglelayerforallRATsandMulti-ConnectivityNCSIPEthernetNewservicesLTE5G

WA,cmW,mmWWiFiLAATightintegration

andcontrolSupportforallservicesandusecasesKeyconcept:FlexibleFronthaulSplitFromidealtonon-idealFronthaulRFPHYMACRCSNCSNetw.Mgmt.lRFPHYMACRCSNCSNetw.Mgmt.lC-RAN(BB-pooling)Distributed(LTE)ExecutedatBSCentrallyexecutedCentrallyexecutedExecutedatRRHCentralizedNCSCentrlized

L1HFlexibleFunctionalSplitIdeal

FronthaulNon-ideal

FronthaulKeyconcept:TopologicalFlexibilityAdapttooperatorinfrastructureandnetworktopology3.)CentralizedScenarioC/U-planeaggregationinthesamesite(LTEDualConnectivitybaseline)Issues:U-Planecapacity(processingandfronthaul/backhaul)inmacroeNodeBCoreCloudsmallcellsmacro2.)DedicatedaggregationforsmallcellsDatacenter1.)Macro-cellasaggregationpointCorecloudmacroU-planeaggregationnodesforreducedx-haulrequirementsdistributedprocessingloadCloud-RANscenariowithcentralizedU-planeandC-planemacrosmallcells5G,WiFi,LAAWiFiCoreCloudOverallarchitectureconcept5G-rtL25G-L15G-RFCorenetwork5G-nrtL25G-rtL25G-L15G-CP5G-RF1.Integratedbasestation5G-nrtL25G-rtL25G-L15G-CP5G-RF5G-nrtL25G-rtL25G-L15G-CP5G-RF5G-RF5G-nrtL25G-CP5G-RF5G-rtL25G-L15G-RF5G-rtL25G-L15G-CP5G-RF5G-rtL25G-L15G-rtL25G-L15G-RF5G-nrtL25G-nrtL22.C-RAN3.FlexibleFronthaulSplit4.DistributedC/U-PlaneBTSBTSRRHRRHBaseBandDUDUCUCU(UP)CU(CP)DURRHBTSFlexibleU-PlaneC-PlaneFlexibleRANArchitectureMSM: MobilityandSessionManagementEntityuGW: User-planeGateWay5G-NB:5G-NodeB,radio,5G-UuterminationX2*: Interfacebetween5G-NodeBsS1*-U: Interfaceforuser-planedatatowardsuGWS1*-C: Enhancedcontrol-planeinterfaceForadetailedfunctionalsplitdescriptionsee[1]and[2]BasicRANarchitectureFunctionalsplitBasicarchitectureLogicalarchitecturewithFronthaulSplitDistributed5G-NBconfigurationFronthaulInterfaceistransparenttoNWandUE:MNCisvisibleas5G-NBfromNWperspectiveMNCmanagesandcontrols5G-RAPsS1andX2interfacesareperMNC,notper5G-RAPs5G-RAPscanbemacro,smallcell,picocell,mmW,…NCSinMNCisresponsibleformulti-connectivityfeatures:aggregation,steering,robustnessSupportforFronthaulSplitandnon-co-locatedUser-planeoffloadLogicalarchitectureSidehaulInterfaceistransparenttonetworkandUESineedstosupportforU-PlaneconfigurationanddataThereisalogical1:manyrelationbetweenMNC-CandMNC-U5G-RAPmayhaveinterfacestoMNC-CandtooneormoreMNC-UMNC-UterminatesS1*-UandX2*-UinterfacestowardsuGW,5G-NBNCSinMNC-UsupportssplitSFtodifferentradiolegssplitSFoverSiinterfacesplitSFtoradiolegofassociatedMNC-UCo-locatedor

non-co-locatedEvolvedCoreCloud5G-NBDedicatednodeforU-PlanefunctionsForscaling,offloadsupportMSMuGWS1*-C5G-RAPPHYMACRCSLegacyLTEeNBC-planeU-planeS1*-USiFs-CFs-UUEUu*UuMNC-UNCSX2-APX2-UMNCRRCNCSWLANAPTWAGWLANACSupportforCloudRANOne-tiervs.two-tierCloud-RANScenariosRadiounitsCentralized/virtualizedhardwareUpperprotocolstackNWinterfaces(S1/X2)RemoteRadioHeadsCentralized/virtualizedhardwareL2+-L3NWinterfaces(S1/X2)L1-L2FronthaulMidhaulCoreNetworkBackhaulCoreNetworkBackhaulFronthaulOnetierTwotierL1-L2L1-L2RRHInterfaceoptionsforFronthaulSplitCoreNetworkCentralUnitUERFL1H-L1LRCSRFCPRI+MACL1logicalNWentityL1-LRFMAC-L1

(notpreferred)L1NCSRCSMACNCSMACRCSNCSRFL1MACRCSNCSNCS-RCSRRCRRCRRCRRCMulti-nodecontroller(MNC)5G-RAPRRCL1-HCPRIbaselinesynchroneousasynchroneous5Gshouldbedeployablesupportingdifferentinfrastructurecharacteristics.OptimalfunctionalsplitmaydependontheavailableFronthaul

characteristicsforlatencyandcapacity.5Gradiospecificationsshouldconsiderfunctionalsplitandnotlimitdeployments.5GLogicalArchitecturalFrameworkforFronthaulSplittoHigherLayerandLowerLayerRF+BB1BB2BB35G-NBFs-U-LFs-U-HFs-C-LFs-C-HFs-OM-LFs-OM-HS1,X2…5G-UuHigherLayerSplitLowerLayerSplitSupportforflexiblefunctionalsplitFlexibilityforFronthaulandServiceRequirementsT1aggregationT2aggregationCorenetworkMNCIdealFHRCSMACL1HNCSRRCuGW/MSMLocaluGWMNCNCSRRCNon-idealFHX2*S1*Fs-HS1*DistanceandlatencytoradioaccessincreasesLowlatencyservicesL1LL1LRCSMACL1RCSMACL1Fs-LMulti-ServiceSupportMulti-serviceMulti-ConnectivitysupportScenario:Inter-5G-NBwithFronthaulSplitSplitbearerat

secondarynodeMaybelocated

inRANcloudMNCcanactasmasterandsecondarynodefromUEperspectiveNCSinMNCresponsiblefor:aggregation,steering,robustnessMulti-connectivityfeatures:NCScanrouteto5G-RAPsoverFsandother5G-NBsoverX2RRC-McanbedislocatedfromNCSuserplaneanchorLocallySwitchedAny-to-AnyConnectivityServicesbelowtheuGW5G-NBModeledwithintegratedPacketDataSwitchAgroupofUEsconnectedtoalocallyswitchedserviceinstancee.g.VLANNote!OnlyUserPlaneConnectivityisshownHostsinaLocallySwitchedServiceassigntheirIPAddressesfromtheuGW(DefaultRouter)LocalSwitchingisexecutedinthe5G-NBintegratedPacketDataSwitchfunctionsProtocolArchitectureKeyconcept:Unifiedprotocolstackfor5GairinterfacePHYMacrooptimized(below6GHz)PHY

EnhancedSC(cmW)PHY

UltraBroadband(mmW)LowerMAC/RRMLowerMAC/RRMLowerMAC/RRM5GConvergenceLayer–CommonFunctionalities(NCSandRRC)

UnifiedUpperLayers–Independentof5GradiointerfacesParameterization,configuration,andimplementationoptimizedforspecificradiointerfacesUnifiedupperprotocolstackforallradiointerfacesRCSRCSRCSIPEthernetAnyprotocolSinglecommonprotocolforallradios:NCS(Networkconvergencesublayer)Flexiblelocation,dependingondeploymentandrequirementsMulti-connectivitytraffichandlingforU-PlaneandC-Plane:routing,splitting,duplicationCommonRRCforcentralizedcontrolofmulti-connectivityfunctionsReducesignalingandcoordinationcomplexityFlexibilityfordifferentmulti-connectivityscenariosNCSastransportlayerforsignalingserviceflowsRadioConvergenceSublayer(RCS)andUnifiedMACParameterizeablefor5GusecasesandrequirementsbasedOptimizedforparallelprocessinginCloudApplicationcontrolschedulingforQoEmanagementandenforcementMainPrinciplesNCSKeyFunctionalityandArchitectureCharacteristicsParticipateinlegaddition/deletionPartitiontrafficacrossmulti-connectivitylegsMulti-connectivityanchorOn-the-fly,identifysub-flowswithinSFAtreceiver,re-orderingper-sub-flowIn-Service-FlowDifferentiationAllowsgranularhandlingofUEtrafficandmulti-connectivityper-SF–e.g.differentlocationsforhigh-andlow-latencySFsAllowMultipleNCSinstancesperUE–oneperServiceFlowNCSlocationinnetworkcanbebasedonQoS,networktopology,multi-connectivitystate,processingloadNetwork-topologyawarenessusinge.g.SDNFlexibleselectionofNCSplacementFlexibleadaptationtochangeinflowcharacteristics,multi-connectivity,processingoverloadNCScanberelocatedAwarenessofstateoflower-layerbuffers,pathandqueueingdelays,etc.oneachmulti-connectivitylegOnDL,FlowControlaidspartitioningoftrafficMulti-connectivityQoSTopologicalflexibilityPHYMACRCSNCSServiceflowNCS-FCP5G-UE:5GUserEquipment5G-NB:5GNodeBProtocolstackUserplaneControlplaneNCS:NetworkConvergenceSublayerRCS:RadioControlSublayerNCS:NetworkConvergenceSublayerRCS:RadioControlSublayer5G-UE:5GUserEquipment5G-NB:5GNodeBNCS-FCP:NCSFlowProtocol(interfaceAP)ProtocolstackWithsupportforMulti-ConnectivityUserplaneControlplaneMSM:MobilityandSessionManagementEntityuGW:User-planeGateWayNCS-SRF:NCSinstantiatedforanSRFUserplaneprotocolarchitectureNCS:CommonconvergencelayerforUP,CP,traffic;Splitting,selection,duplicationofpackets;selectionofradiolegs;withinthenetwork,maynotbeco-locatedwithRCS.RadioFlow:

RFListheserviceprovidedbytheLayer2fortransferofdatabetweenUserEquipmentand5G-RAN.RadioSubFlow:TheserviceprovidedbyNCSlayerfortransferofdatabetweenUEand5G-RANmappedtoaspecificQoSQueue.RCS:Buffering,Segmentation,ARQ,re-orderingMAC:Multiplexingtotransportchannels,radio/QoSschedulingQoSArchitectureServiceflow(SF)providesendtoendconnectivitybetweentheUEandtheServiceedgeS1*connectiondeliversserviceflowpacketsbetweentheRANandtheuGWRadioFlowandRadioSub-Flows(RSFL)transportSFpacketsbetweenthe5G-NBandtheUE.ThedatapacketsoftheSFcanbemappedtomultipleRSFLs,eachrepresentingaradiolevelQoSclass.AradiolinktransportsRSFLpacketsbetweentheUEandtheAP.ThereisonetoonerelationshipbetweentheRSFLandtheradiolinkinsingleconnectivitycase.Inthecaseofmulti-connectivity,RSFcanbemappedtomultipleradiolinkseachbelongingtodifferentradio.QoSArchitectureASclassifiesapplicationflowsintosub-serviceflows(SSFs)andperformsschedulingTheASinformsthe5G-NBaboutthespecificserviceattributesandtheidentificationofSSFs.BasedonthereceivedSSFlevelinformation,5G-NBconfiguresitsradiostackTheRFLsplitfunctionoftheAPmapsdatapacketstoRSFLbasedontheSSFinformation.Applicationscheduler(AS)QoEManagementandcontrolclosetoRANorinCNBasicprinciples:OneNCSentityservesoneServiceFlow(radioflow)OneRCSentityservesoneNCSentityMultipleRCSentitiescanservethesameNCSentityConfiguration,setupandoperation:Duringsetup,atleastoneRCSentityisconfiguredforthesetupNCSentitywithdefaultconfigurationandQoS.Thesetupandterminationofradio(sub-)flowsisperformedbyRRC.NCScanroutepacketstomultipleRCSentitiesindifferentradiolegsbelongingtothesameRadioService.Radioscheduler/MAChasnovisibilitytoapplicationflowsoraradioservicesbutseestheRCSentities/buffersMappingfromNCStoRCSandQoSqueuesExampleofwithtworadiolegs(multi-connectivity)andtwoserviceflowsControlPlane-RRCRCSMACPHYRRCNCSRCSMACPHYRRC-SControl-PlaneprinciplesRRCNCSX2*ToCore(S1*-C)5G-UERCSMACPHYRRCNCSRCSMACPHYRRC-SRCSMACPHYRRCRCSMACPHYRRC-SRCSMACPHYRRC5G-uUcmWaveradiolegWidearearadiolegmmWaveradiolegX2*orFsRRC-MasterRRC-ScoordinationUEstatemanagementLocalRRC(transparent)implementsconfigurationbyRRCmasterNotvisiblebyUENCSRoutingofRRCanduser-planemessagesSelectionofradiolegs,implementationofreliabilityschemesLogicalview:OneRRCentityinUEcommunicateswithRRC-MoverdifferentradiolegsTransportview:NCSperformsmessageroutingforRRCfromandtodifferentradiolegsKeyconcept:SeparationoflogicalfromtransportplaneforcontrolmessagesRRCinUESingleRRCentityforallradiolegsSinglestatemachineRCSMACPHYRRCSignallingradioflow(SRF)Baseline:Multi-connectivitywithsignallingreliabilitySingleRRCMotivation:- Multi-connectivitycontrolbasedonDualConnectivityprinciples- Supportforsignallingrobustnessbyusingmulti-connectivityPrinciples:- M5G-NBhostsRRC-Masterandisthemobilityanchor.OneormoreS5G-NBsprovideadditionalresources(i.e.radiolegs)totheUES5G-NBhostsatransparentRRCentityinvisibletoUEhandlesradioparametersforS5G-NBAdditionRequestmaintainsalocalUEcontextRadioleg1andRadioleg2providediversityforRRCsignallingOption:RRC-MandRRC-SDirectmessagetransferfromRRC-SMotivation:AvoidsignalingtoM5G-NBandCNforpathswitchFastreconfigurationofS5G-NBradiolegs(e.g.,intra-S5G-NBHO)TerminationofmeasurementsatS5G-NBRoleofRRC-M:- AllRRCservicesandfunctions(includingUEstateassignment)- CoordinationwithRRC-SRoleofRRC-S:ConfigurationS5G-NBradiolegsandresources(pre-agreedwithRRC-M)TerminationofSRFMeasurementprocessingforS5G-NBIntra-S5G-NBHand-OvercontrolNotes:OneormoreRRC-ScanbecontrolledbyasingleRRC-MUEmaintainsasingleRRCstatewhichcombinesRRC-MandRRC-SconnectionsLTE-5GandMulti-RATintegrationPhaseI:LTEasAnchor+5GStandaloneLTE-5GinterworkingPhase1:Early5GradioEarly5GradiooptimizedforeMBB5G<Edualconnectivity5GinstandalonemodeDynamicQoSframeworkMobilityframeworkNetworkslicing(Core)FlexiblescalabilityofCP/UPfunctions.MinimumfeaturesettoensureforwardcompatibilityforcMTCandmMTCusecasesLTE-anchoredsolutionforphase1isnotrequiredtosupportnew5Gfunctionsfore.g.Idlemode5GmobilityPagingThosefunctionsareLTEbased.PHY,MACand5GRCSshallsupportmain5Gfeaturesandshallbeforwardcompatibleforphase2(supportofMTC,IoT,V2X,D2D…).X2-Uextensionsfor5GarelikelyX2+Phase1InterworkingbasedonLTEdualconnectivityoptions5GRCS5GRCSFromPDCPtoNCSEvolutionofLTEDualConnectivityMCGbearersplitbearerPDCPRLCPDCPRLCMACMACRLCMeNBSeNBPDCPRLCPDCPRLCMAC5G-MAC5G-RLCFronthaulsplitRANCloudMC-PDCP(NCS)Fronthaulsplit:LowLatencyIPIPIPEther-netAnyProt.EvolvedRANCloudAlsootherDC

optionspossibleLTE-RLCLTE-MAC5G-RLC5G-MACPHYWiFiMACMonolithicarchitectureeNBeNB5G-PHYLTE-PHYLTE-PHY5G-PHYWiFI-PHYMulti-connectivity:GeneralizedDCfor5GCloud-based5Garchitecture

GeneralizedDualConnectivity(Multi-Connectivity)

SameprotocolforanyRAT:NCSScalabilityinevolvedRANcloudCoexistswithbothlow-latencyandhigh-latencyFHLTEradiocloudwith5G

ScalableandFutureproofWorksforhigh-latencyFHBaseline–LTERel.12DualConnectivity

IPIP5G-RLC5G-MAC5G-L1’5G-PHY’’LTE-RLCLTE-MACLTE-L1’Fronthaulsplit:HigherLatencyPhaseII:5GasanchorFullintegrationof5G,LTE,WiFi5GNCSRLC5GRRC4GMAC4GPHY5GNASPDCPRLC4GRRC4GMAC4GPHY4GNASHybridmacroLTEeNBProtocolstack5GUE4GUEIntra-5GMulti-ConnectivityOptionsUltra-highreliability5GMulti-connectivity–OneofthekeystotheprogrammableworldMassive

machine

communicationExtreme

Mobile

BroadbandCritical

machine

communicationThroughputEnhancementSeamlessMobilityUltra-lowsignalinglatency01010

0101011

101010101

01011001

ConnectionRobustnessMulti-connectivityInter-frequencyCarrieraggregation(intra-site)Datasplit/duplicationDualConnectivity(inter-site)RRCdiversity/M/S-RRCInter-RATIntra-frequencyIntra-siteCoMPSFNJT-CoMPDPS-CoMPUL-CoMPInter-siteCoMPFastreroutingMulti-connectivityVariantsfor5Gf1f2Throughputenhancement/Ultra-highreliabilityMobilityrobustness/Ultra-lowsignalinglatencyCell-edgeThptenhancementConnectionrobustnessMulti-ConnectivityOptions–intra-frequencyDataENC,MOD,OFDM,etc.w2*w1*JointTransmission?Virtual/phantomCell“CoherentFBandcalibration~Singlecellwithdistr.antennasJointMACneededDataENC,MOD,

OFDM,etc.ENC,MOD,

OFDM,etc.FastCellSelectDoesnotnecessarilyrequirejointMACUpperLayer(L2-U)wouldbeslowerbutstillfast…DataENC,MOD,

OFDM,etc.ENC,MOD,

OFDM,etc.DeMUXMulti-linkIndependentdataandindependentschedulingHigherLayeroption

(lowerlayerincludedasMIMOinJT/SFN)DataENC,MOD,OFDM,etc.SFNClassicalSFNgainJointMACneeded

(SamePRBsmustbescheduled!)Requiresjointlayer2(L2-L)

(=“jointMACscheduler”)Possiblewithout

jointlayer2(L2-L)5GLTEEvolutionfromLTEdual-connectivityto5Gmulti-connectivityIntra-siteCoMPAppliedtouser-planeToimprovecell-edgeperf.Intra-site&inter-siteCoMPFastreroutingsupportedAppliedalsotocontrol-planeToimprovemobilityrobustnessIntra-RI&Inter-RICADataduplicationsupportedAppliedtoalsocontrol-planeToachieveultra-highreliabilityIntra-RICADatasplitassumedAppliedtouser-planeForthroughputenhancementExtendedDCEnhancedDCoptionsDataduplicationsupportedRRCdualconnectivitydefinedForconnectionrobustness,ultra-highreliability,ultra-lowsignalinglatencyDualconnectivityDatasplitassumedAppliedtouser-planeForthroughputenhancementUPorCPMulti-Connectivity?#1.UP-Multi-connectivity#2.CPmulti-connectivity#3.FullAP1AP3AP2AggregatingradioresourcesinmorethanoneeNBforuserplandataTx.Controlplaneaswellasmobilitystillinonecellonly.AdoptedinLTEE.g.CoMP,cellaggregation,CA,DualconnectivityAP1AP3AP2HandoverrelatedRRCsignallingcouldadditionallybetransmittedfromortoapotentialtargetcelle.g.RRCdiversity,ormultipleRRCUserplanestillinonecellonly.NotusedinLTEyet.AP1AP3AP2BothCPandUPconnectedtomultiplecells.E.g.Inter-noderadioresourceaggregation+RRCdiversityNotusedinLTEyet.CPUPM5G-NBhostsM-RRC.S5G-NBhostsRCSincaseofsplitradioflow,NCSotherwise.SplitRadioFlowcanbelocatedatM5G-NBorS5G-NB:S1-Ucombinedwithsplitradioflow(i.e.,inLTE-DCterms,options1aand3ccombined)FFS

whethersplitradioflowfromS5G-NBtootherS5G-NBshouldbepossible.Multi-ConnectivityInter-5G-NBProtocolarchitectureMobilityrobustnessthroughmulti-connectivitySimulationofRLFUsersStreetScenario:CorrespondstosingleconnectivityDespiteaggressiveMCsettings,50%singleconnectivityMobilityrobustnessthroughmulti-connectivityRadioLinkFailurevsThroughputWithMC,5-%ThroughputisimprovedbecauseofCombinedschedulingandlowmobilityproblems.Asexpected,thethroughputatrelativelyhigherActiveSizeconfigurationdeclinebecauseresourcesfrommorecellsareblockedbyusersofveryhighactivesetsize.MobilityproblemsareimprovedwithMCMobilitymanagement-selectedaspects-ExistingHandoverMechanisms:TwomainstreamsNWcontrolledUEautonomous0.Measurementreport1.Preparation2.Scheduling3.Command4.ReadyforTx2.RACH4.ReadyforTx3.Command1.ByeNote:authenticationinformationandpacketforwardingisnotshowninthisfigureandneededforboth2*.Context&packetforwardingMeasurementtime:Canitbeshortened?Whattomeasure?Slowchannelchanges(pathloss)Whattofilter?Fastfading,noise…“Filter”fastfading(Rayleighfading)AveragingalongslidingwindowDiversityorder: =independentchannelrealizations(duetoMIMO,coherencebandwidth)BigbandwidthDoesnotimprovethings:shortdelayspreadhugecoherencebandwidthOnlylimitedreductionofmeasurementtime(10sofms)10110210310400.511.522.5slidingwindowsizein[ms]standarddeviation(indB)3km/h;carrierfrequency15GHz

diversity=4;periodicity=1msdiversity=4;periodicity=5msdiversity=4;periodicity=10msdiversity=4;periodicity=20msdiversity=8;periodicity=1msdiversity=8;periodicity=5msdiversity=8;periodicity=10msdiversity=8;periodicity=20msdiversity=16;periodicity=1msdiversity=16;periodicity=5msdiversity=16;periodicity=10msdiversity=16;periodicity=20msref:orig.fading,unfiltered10110210310400.511.522.5slidingwindowsizein[ms]standarddeviation(indB)3km/h;carrierfrequency3.5GHz

diversity=4;periodicity=1msdiversity=4;periodicity=5msdiversity=4;periodicity=10msdiversity=4;periodicity=20msdiversity=8;periodicity=1msdiversity=8;periodicity=5msdiversity=8;periodicity=10msdiversity=8;periodicity=20msdiversity=16;periodicity=1msdiversity=16;periodicity=5msdiversity=16;periodicity=10msdiversity=16;periodicity=20msref:orig.fading,unfilteredUplinkcanonlybemeasured,iftheterminalisTransmitting(atall)Regularlytransmitsabroadbandsignal(justasDLreferencesignals)Withwell-knownpowerConclusions:CanNOTrelysolelyonmeasurementobtainedviareciprocityBScanmeasureforeignUEsonlyif“prepared”,unexpectedcellswillbemissedandonlyifBSisalsoinULstateCanusereciprocitytoimprove/assistmobilityinsomesituationsasbesteffortfeatureCostsarenotsignificant(ifsyncissufficient),atleastnotintheintra-cloudcaseCanchannelreciprocitybeexploitedformeasurement?DLReference

Signal(regular&broadband)UEMeasurement

ReportNeighborAForwardofBSmeasurement(X2-like)ULSignal(Sounding,RACH,

ULControl,etc.)Serving

cellBNeighborAServing

cellBClassicalapproachExploitingReciprocityFindings–HowtodecreaseHOlatency?NWControlledUEautonomousTodecreaseHOinterruptiontime:RACH-lesshandoverAvoidingsysteminformationreadingNote:SinceX2latencyvaries,thescheduletheTargetsendsinadvancethroughSource(inter-siteHO)hastobeconservative,oralongerthanneeded(forthedata)resourcereservationhastobemadeTodecreaseHOinterruptiontime:Fastersysteminformationreadinge.g.broadcastneighborcellBSIsattheSource)Sourcecouldsendan[ACK+TargetBSI+schedule]asaresponsetotheByemessage1-stepRACHTodecreaseHOreactiontime:Shortermeasurementtime:RobustnessagainstfailureisdominatedbyUEmeasurements.MinimizingbackhaullatencyIfpathswitchcouldbeinitiatedearlier,itwouldsavetime(itwascommentedthat,incaseofHOfailure,recoverymaybecomplicated)NW&UEAlwaysonApplications:needtosendandreceivesmallpacketsfrequentlytokeepIPconnectivityopen.Thisiscalled“heartbeat”or“keepalive”Thetypicalfrequencyof“keepalive”isonceperminute,oronceeveryfewminutes,andtheamountofdataisverysmall(<<1Kbyte)Keepalivemessagesaretypicallygeneratedbytheapplicationwithoutanyoptionforthenetworktocontrolthem“Smart”problemwith“always-on”applications:MultipleapplicationsrunontopofeachotherwithindependentheartbeatsThiscausesfrequentIDLEtoCONNECTEDmodestatetransition,atthecostofincreasedC-plane(26inLTE)signallinginthenetwork,higherpowerconsumptionandinsufficientradioresourceusage.SmartPhoneProblem~x-secondsTrafficDifferentapplicationsmayhaveKeepAlivemessagingwithdifferentfrequencyandsizeinstantmessaging,pushemail,locationservices,weatherwidgetsetc.

PotentialcharacteristicsofthenewRRCConnectedInactivestate:Configurablebasedonthere