2024 全球6G技術(shù)大會 -10.0H User-Centric Access Network Technology Research for 6G

2 2 2 3 4 4 6 8 8 9 12 184.1AccessandConnectionManagementTechno 194.2NetworkingandDeplo 214.3MobilityManagementTechnolo 234.4FlexibleandEfficientUserPlaneTransmissionTechnol 284.5User-CentricResourceOrchestra 304.6DistributedMulti-AntennaTechnolo 344.7TerminalKeyTechnol 354.8User-CentricConvergenceTechno 36 37 37 38 40Chapter1IntroductionTheadventofthe6thgenerationmobilecommunicationnetwork(6G)promisestointroducenewperformancemetricsandapplicationscenarios.Auser-centricnetworkispoisedtobeakeytechnologydrivingtherealizationofthe6Gvision,asitbreaksawayfromthetraditionalparadigmofa“basestationcentric”networkandeffectivelyintegrateswithemergingtechnologiesintheinformationindustry.TheInternationalTelecommunicationUnionRadiocommunicationsector(ITU-R)highlightsinits"FutureTechnologyTrendsofTerrestrialInternationalMobileTelecommunicationsSystemstowards2030andBeyond"reportthat,asanewtypeofnetworkarchitecture,user-centricarchitecturetechnologycanenhanceRadioAccessNetworks(RAN)[1].ThiswhitepaperdelvesintotheresearchonUser-CentricAccessNetwork(UCAN)technologyfor6G.ItbeginsbyintroducingthebackgroundofUCANtechnologyresearchandexplainstheconceptandgoalofuser-centricin6G.Chapter2outlinesthescenerequirementsandevaluationmetricsforUCAN,whileChapter3delvesintothedesignofuser-centricaccessnetworksystems,encompassingfivemajorfunctionalcharacteristicsandarchitecturaldesigns.Chapter4discussesthekeytechnologiesoftheuser-centricaccessnetwork,andChapter5concludesandprovidesafutureoutlook.Facedwithincreasinglycomplexnetworkenvironmentsanddiverseservicerequirements,thelimitationsofthetraditionalcellulararchitecturearebecomingincreasinglyprominent.Thehighpathlossofdatatransmissionattheedgeofcellsandunpredictableinterferencefromneighboringcellsleadtoimbalancesinuserdataratesbetweenthecellcenterandcelledge.Additionally,duringmobiletransitions,handoversatthecellularedgemaycauseserviceinterruptionsanddelays.Asthecellularcoverageareacontinuestoshrink,theseissuesbecomemoresevere.Toenhancenetworkqualityofserviceandrobustness,variousedgeenhancementandmobilityoptimizationsolutionshavebeenproposed,andstandardized:Forcelledgedatatransmission,4Gand5GhavesuccessivelyproposedkeytechnologiessuchasCoordinatedMultiplePointsTransmission/Reception(CoMP)andMulti-TransmissionReceptionPoints(Multi-TRP).CoMPenablesdifferentcellswithinasinglebasestationtosendandreceivethesameordifferentdatatoasingleuser[2].Multi-TRPallowsmultipleTRPstocooperateinsendingandreceivingthesameordifferentdatatoasingleuser[3].However,duetothelimiteduserscale/coverageareaofasingleDistributedUnit(DU),thedynamiceffectsofMultipleTRPcollaborationareconstrainedbyoperationsacrossDUsthroughtheCentralizedUnit(CU),andthedelayincrease/datainterruptioncausedbytheterminalswitchingbetweenDUs,thisoptimizationonlyimprovestheedgeperformancewithlimitedgainandbringsadditionalsystemcomplexity.Toenhancemobility,5GintroducedtechnologieslikeConditionalHandOver(CHO),DualActiveProtocolStack(DAPS),andL1/L2-triggeredMobility(LTM)toaddressservicecontinuityandseamlesstransitionissuesduringterminalhandovers.CHOconfigureshandoverconditionstotheUserEquipment(UE),allowingtheUEtodeterminethetimingofhandoversbasedonconditions.DAPSactivatestwoprotocolstackssimultaneously,ensuringuninterrupteddatatransferduringthehandoverprocess.LTM,throughL1/L2signaling,performsmeasurementreportingandcellhandovers,reducingmobilitydelays[3].ItcanbeseenthatCHO,DAPSandLTMarealloptimizationsofthehandoverprocess,anddonoteliminatethehandoverprocess.Theterminalsstillneedtoperformhandoverswhenmoving,andthiswillbecomemorefrequentinenvironmentswithsmallcellcoverage,therebyincreasingsignalinginteractionsbetweenterminalsandnetworks,aswellaspowerconsumptionforbothterminalsandnetworks.Theprevalenceofsmallcellcoverageisexpectedtobeevenmorewidespreadin6G.Inaddition,althoughtheseenhancedfeaturesprovidecertaingains,theyarealllimitedandrequiretheterminaltohavecorrespondingcapabilities,whichincreasesthedesigncomplexityoftheterminal.Furthermore,solutionsbasedonCentralizedRadioAccessNetwork(C-RAN)definingsuper-cellapproacheshavebeendiscussedintheindustry.However,consideringthephysicallayerdesignbasedonexistingtechnologies,suchasterminaladdressingbasedonPhysicalCellIdentity(PCI)andCellRadioNetworkTemporaryIdentifier(C-RNTI),themaxnumberofuserinthesuper-cellcanonlybethemaximumsupportedbythecurrentstandarddesign.Thisapproachnotonlyfailstofundamentallyaddressthelogicalconstraintsofexistingradioaccessnetworksbutalsointroducesanadditionallayeroflogicalconstraintswithsuper-cell,increasingsystemcomplexity.Insummary,priorto6G,mobilecommunicationhasbeendevotedtoincrementalcorrectionsbasedonthebasicarchitectureofcellularnetworks.Althoughsomeenhancementtechnologieshavebeenintroduced,providingcertainperformancegains,theyarelimitedbythestrongbindingrelationshipbetweenbasestationcellsanduserterminals.Ononehand,theycannotfundamentallysolvetheproblemandarenotapplicabletoallterminals.Ontheotherhand,theyintroducesignificantcomplexitytobothbasestationsandterminals,hinderingdeviceandoperationalcostmaintenance.Intheeraof6G,newtrends,drivenbynewscenarios,frequencybands,andtechnologies,forceustoreconsider,reflect,andexpandourunderstandingofuser-centric.Inthisprocess,theconceptof"User"isfurtherexpanded,encompassingnotonlytocustomer(toC)userssuchasmobilephonesbutalsotobusiness(toB)users/customers,includingindustryapplicationsandnetworktenants,coveringbothcontentprovisionandconsumption."Centric"referstoempoweringuserswithcertainautonomythroughcustomizablenetworks,providingfriendlynetworkinteractionandcustomizationforusersthroughopennetworkinfrastructure(channels,computingpower,sensing,intelligence,etc.),andestablishingasounduserexperienceevaluationsystem.Thegoalofuser-centrichasbeenlong-standing.Fromanapplicationlayerperspective,end-to-endnetworkservicesaimtofulfilluserdemands.Regardingphysicallayertransmissiontechnology,thebesttransmissionperformanceinvolvesarbitrarynodeconnectionswithoutconsideringcellularnetworkrestrictions.However,thesetwoidealswerepracticallyunattainablein5Gnetworks.Toachievetheultimateend-to-enduser-centricandoptimizephysicallayertransmissiontechnologywithoutconstraintsfromcellularnetworkarchitecture,logicalreconstructionofaccessnetworksisrequired.6GUCAN,whichisnotconstrainedbythedeploymentofhigh-levelnodes,servesasanaccessnetworkcenteredaroundusersandservices,flexiblyorganizingnetworknodesandresourcestoserveusers.UCANadaptsflexiblytotheneedsofusersandservices,withadesigngoalofconsistentuserexperience(i.e.,UEcanobtainresourcesforuplinkanddownlinktransmissionasneededfromanylocation),avoidingcomplexandredundantpatchworkconstruction,andadheringtothelawsoftechnologicalevolutionandindustrialdevelopmentforsystemarchitectureandkeytechnologyresearch[4].TypicaldefinitionsofUCANinclude:Intermsofarchitectureandnetworking,thenetworkwillprovideuserswithhigherfreedomandsupportdeepcustomizationbasedonuserportrait.Differentnetworkarchitectureorganizationsanddeploymentformscanbeusedfordifferentusersandserviceapplicationsdynamically.Thenetworktracksandmaintainsusercontextforthelongterm,perceives,analyzes,andintelligentlypredictsinformationrelatedtousersandservices,thussegmentingandfriendlyhandlinguser/terminalrequests.Itquicklyconstructsnewbusinessesanddeployswirelesstransmissionservices,providingefficientconnectionmanagementmechanismsandtopologyadaptivemechanisms,suchasuser-intent-drivenanduser-interest-sensingdesigns.Intermsofresources,thedevelopmentofnewtechnologiessuchascloudcomputing,bigdata,andAIhelpsthenetworkestablishandmaintainanoverallviewandschedulingmanagementofmulti-dimensionalresourcessuchasconnections,computingpower,data,andmodels.Thisensuresreal-timeandprecisedeliveryofvariousresources,suchasbeams,bandwidth,power,TRP,channels,andlinkinterfaces,optimizingenergyandspectrumefficiency,keepinguserterminals(groups)alwaysintheoptimalservicestate.Intermsofuserservices,thenetworkgrantsusersgreaterautonomy,meetingdiverseconnectivityandnetworkingneedsfordifferentusers/terminalsinvariousscenarios.Userscanautonomouslyselectthenetworktype(e.g.,Sidelink,V2X,NTN)basedonterminalcapabilities,servicerequirements,andnetworkconditionsormakemobilitydecisions.Theycanalsoprovidefeedbacktothenetworkbasedonserviceornetworkingrequirements,requestingthenetworktocoordinatecorrespondingresourcesandconfigurations.Thisallowsuserstoswitchbetweenterminalsandnetwork(orrelay)nodesasneeded,offeringandusingservicesaccordingly.Chapter2ScenariosandRequirementsUser-centric6Gradioaccessnetwork,buildingupontheapplicationsservedby5Gtechnology,willachieveon-demandflexiblenetworkingacrossmultipledimensions,includingspectrumresources,functionality,services,computingpower,andsecurity,cateringtobothtoBandtoCusers.Thisintegrationaimstomeetthediverserequirementsofemergingfusionservices.Itnotonlyprovidespersonalizedservicessuchasmobilitymanagement,policycontrol,sessioncontrol,andpersonaldatamanagementbutalsooptimizessignalingoverheadandnetworkperformanceattheuserlevel.Itispoisedtobecomeoneofthedisruptivetechnologiesinthe6Gera.?NovelConvergedNetworksLookingatthefuture6Gnetwork,thereisanurgentneedtoachievefullcoverage.Itsconvergednetworkdeploymenttypesincludebutarenotlimitedto,ultra-densenetworks,wide-areacoveragenetworks,edgecloudnetworks,integratedspace-terrestrialnetworks,andUAVnetworks.Creatingafusionthree-dimensionalnetworkisafocalpointof6Gdevelopment.Theuser-centricaccessnetworkcanaccommodatevariousnetworktypes,suchastheInternetofThings(IoT)andmobilebroadbandnetworks.Itprovidespreciseservicesforusersunderdifferentnetworkarchitecturesbyselectingavailableaccesspointsbasedondemand.?ImmersiveServiceCommunicationWiththerapiddevelopmentof5Gstreamingandmultimediaservices,immersivecommunicationbasedonExtendedReality(XR)communication,holographiccommunication,remotemulti-sensoryintelligentcommunication,andotherdiversifiedservices,isexpectedtobecomekillerapplicationsof6G,whichcanprovideuserswithimmersiveuserexperiences.Immersivecommunicationscenariosrequirethenetworktoprovideultra-highdataratesandultra-lowlatency,ultra-highreliabilityperformanceguarantees.Tothisend,realizingauser-centricaccessnetworkarchitecturewillbecomeanimportantconsiderationforbuildingthisservice.UCANguaranteesindependentservicetransmissionforeachuserthroughmulti-nodecoordinationandflexiblegroupingsettings.Atthesametime,itprovidesuserswithmoreflexibleandricherresourcestomeettheneedsofhigh-trafficservicesacrossthenetwork.?Communication-Sensing-ComputingIntegration6Gnetworkscanutilizecommunicationsignalstoachievesensingfunctionssuchasdetection,localization,recognition,andimagingoftargets,acquiringenvironmentalinformationforenhanceduserexperiences.UCANnotonlypossessesstrongsensingcapabilities,includinguserservicerequirementsbutalsoswiftlyanduniformlycoordinatescomputingresourcesamongmultipleuserstomeetthenetwork'scomputingdemands.Thisachievestheperformanceofintegratedsensing,communication,andcomputationnetworks[4].?IntelligentServiceScenariosIntheeraof6G,withtheblueprintofcreatingaworldwhereeverythingisintelligentlyconnected,therewillbeanincreasingnumberofnewintelligentterminals.WiththeassistanceofAItechnology,intelligententitiescancontinuouslylearnandautonomouslycollaborate,empoweringapplicationsinsmarthealthcare,industrialIoT,smarthomes,autonomousdriving,andmanyothers.DrivenbyAItechnology,UCANdetectsusersandtheirservicerequirements,adaptivelyconstructsflexiblecellsforusers,andachievespathselection,wirelessresourcecoordination,andaccessnodeselectionnetworkfunctionalities.Additionally,leveragingthedistributedcollaborativecapabilitiesamongmultiplenodes,itaddressespainpointssuchasdatastorage,computation,andprivacyprotectioninintelligentscenarios.2.2.1SeamlessConneSeamlessconnectivityprimarilyreferstomeetingtheuser'sneedforconnectivityandcommunicationanytime,anywhere.Asserviceintegrationprogressesanddeploymentscenariosexpand,usersrequireconnectivityandcommunicationinvariouslocations,suchasonairplanes,inremoteareas,andinmaritimezones.Tomeettheuser'sdemandforaseamlessconnection,the6Gnetworkwillextendcontinuouslytowardthespace,air,ground,andsea.Thegroundcellularnetworkwillbeintegratedwithspacenetworksincludinghigh-orbitsatellitenetworks,medium-andlow-orbitsatellitenetworks,high-altitudeplatforms,andUAV,asshowninFigure2.2-1.Itwillbuildglobalwide-areacoverageofaspace-air-groundintegratedthree-dimensionalnetwork,achievingtheeffectthatanyonecancommunicatewithanyoneatanytimeandanywhere.Figure2.2-1User-CentricSeamlessConnectivityNetworkDiverseconnectivitymainlyreferstothedifferentiateddemandofusersforconnectioncapabilities.Itisnecessarytoprovideuserswiththebestconnectionservicetomeettheirneeds.Withtheconnectionofpeople,machines,andthings,andtheconnectionbetweenthephysicalandvirtualworlds,therearealargenumberofconnectablephysicalentities,asshowninFigure2.2-2,includingsmartterminals,sensors,wearabledevices,vehicles,andindustrialcontrolequipment.Duetothediverserequirementsofdifferentusersforconnectioncapabilities,providinguserswithoptimalconnectioncapabilitiesanddeployingconnectionfunctionalityondemandrequiresauser-centricapproach.Itsupportstheintelligentinterconnectionandfusionofvariousheterogeneousnetworks,dynamicallymeetingcomplexanddiversescenariosandservicerequirements,includingfutureapplicationslikeunmanneddriving,smarthomes,andvirtualreality.Itmeetsthedemandsforhighbitrates,lowlatencyjitter,andhigherreliabilitywhileachievingnetwork-sideintegrationofmulti-access,connections,andservices.Figure2.2-2User-CentricDiverseConnectionNetworkAsinfrastructuresuchasnetworks,AIcomputing,andedgecloudcontinuestoimprove,andwiththepopularityofonlineeducation,livee-commerce,metaverse,remotehealthcare,andwidespreadentertainmentandsocialactivities,thereisacontinuousincreaseinuserdemandsforhigh-trafficapplicationsandthespeedofInternetofeverything.Forinstance,metaverseservicesrequirereal-timedatatransmission,real-timeaudio-videocommunication,andthecapabilitytosupportmultipleuserssimultaneouslyonline,necessitatingnetworkstoprovidehigh-speed,low-latencydataservices.Therefore,auser-centricnetworkneedstoofferhigh-speed,low-latency,andhighlyreliabledatatransmissionaccordingtouserrequirementstobettersupportreal-timeandhigh-speedapplications.2.2.4Data-DrivenComputiWiththeadventofthe6Gera,thedegreeofdigitizationisdeepening,andglobaldata-driventrendsareaccelerating.Real-timedataprocessingandultra-large-scaledeviceconnectionswillbringpeopleanincreasinglysophisticateduserexperienceandconvenientlife.Thistrendalsoplaceshighdemandsoninformationprocessingcapabilitiesbasedoncomputingpower.UCANnotonlyneedstoproviderobustcomputingsupportbutalsorequirestheabilitytodynamicallyschedulepersonalizedresources.Thefocuswillbeonhowtoscheduletaskstomatchcomputingresourcesbasedonusers'differenttaskrequirements.DesigningincentivemechanismstoencourageuserstocoordinateandallocatecomputingpowerandultimatelyachieveefficientempowermentofcomputingresourceswillbecomeoneofthekeydirectionsforfutureUCANconsiderations.2.3EvaluationMetrics?LatencyControlplanelatencyreferstothetransitiontimefromthemost"battery-efficient"state(e.g.,idlestate)tothestartofcontinuousdatatransmission(e.g.,activitystate).Thegoalin5Gis20ms(eMBB,URLLC).UCANadoptsacloud-basedcontrolplanecentralizedschedulingsystem,expandingthe2-stepRACHwithintheCCU(Msg1andMsg3,Msg2andMsg4combiningtoreduceRACHlatency),furtherreducingcontrolplanelatencyin6G.Simultaneously,theimprovementinhardwareprocessingcapabilityeffectivelyshortensthemessageprocessinglatencyforUEandTRP.?MobilityMobilityinterruptiontimereferstotheshortestdurationduringwhichauserterminalcannotexchangeuserplanenetworkpacketswithanybasestationduringamobilitytransition.ThemobilityinterruptiontimedelaytargetofbeammobilityandCAmobilitydescribedin5Gfeaturesis0ms.UCANusesmultipleTRPstoserveasingleUE,andthemobilityinterruptiondelayiscloselyrelatedtotheTRPorganizationproblem.SincetheseTRPscanbelocatedunderthesameDDUordifferentDDUs,TRPorganizationcoordinatedbyCCUandDDUcanachieve0msmobilityinterruptiondelayinbothinter-DDUandintra-DDUscenarios.?SystemCapacitySystemcapacityisdefinedasthenumberofuserssatisfyingspecificservicesinacellorgeographicalarea(m2).Thespecificindicatorsare:Y%ofUEsintheareameettherequirements.ThejudgmentstandardforUEstomeettherequirementsisthatallflowsreachthedataerrorrateanddelaybudgetrequirements,thatis,morethanX%ofthedataissuccessfullytransmittedwithintheairinterfacedelaybudget.TypicalvaluesforXandYare90and99.Thisdefinitioncomesfrom3GPPXRcapacityevaluation.Immersiveservices,representedbyXRservices,arerecognizedasfeaturedapplicationsin6G.Immersiveserviceshaverequirementsforhighspeed,lowlatency,andhighreliability.Existingsinglemetricssuchaspeakrate,spectralefficiency,latency,andreliabilityarenotsufficienttocharacterizesystem-levelsatisfactionforsuchservices.Tomoreintuitivelyreflectthedifferentuserandservicerequirementsof6Gcomparedto5G,itisnecessarytodefinesystem-levelmetricsforsuchservices.Systemcapacityisanintuitiverequirementfor6Gnetworkoperationand6Gfeaturedusersatisfaction.Chapter3SystemDesignThesystemdesignoftheuser-centricaccessnetworkincludesthefollowingpaths:1)Realizebasicfeaturessuchasuser-centricconnectionandtransmissionthroughsimplifiedandoptimizedunderlyingdesign.2)Implementanend-to-endarchitecturefortheuser-centricnetworkfromtheoverallarchitecturelevel,adoptaunifiedandsimplifieddesignfordifferentaccessmethods,andintroducenativeintelligence,integratedsensingandcommunication,andcomputingcollaboration.3)Exploremoreinnovativedesignstoachievearchitecturesthataremoreconducivetouser-centric,suchasnewsecurity(e.g.,blockchain)andtightcouplingoftheapplicationlayerwiththeaccessnetwork.Figure3-1DesignRouteofUser-CentricAccessNetworkThischapterfirstintroducesthemainfeaturesoftheUCANsystemarchitecture,andthen,addressingthefirstdesignrouteissue,proposesaCCU-DDU-TRParchitecturebasedontheevolutionof5G.Then,basedontheresearchonthefollow-updesignrouteissuesandtheexplorationofnetworkarchitectureevolution,possibledesigndirectionsaregiven.User-centric,asamajorfeatureof6Gnetworks,enablesthenetworktointelligentlysensetheuser'swirelesscommunicationenvironment,andthenflexiblyorganizetherequirednetworkaccesspointsandresourcestoservetheuser,makingtheuseralwaysfeelatthecenterofthewirelesssignalcoverage.Toembodyuser-centricandmeetdiversescenariosandneeds,user-centricnetworksmainlypossessfivekeycharacteristics:deepcustomization,elasticreconfigurability,opennessandcompatibility,intelligentadaptiveuserservices,andenhanceduserrights.3.1.1DeepCustomizaInthetraditionalsense,acustomizednetworkmeansadedicatednetwork,thatis,usingaspecificfrequencytoservespecificusersinaspecificarea.Inthe6Gera,thenetworkneedstoputuserneedsatthecoreofnetworkdesignandoperation,meetuser-specificrequirementsforthenetwork,providecustomizedfunctionsandservicestoimproveusersatisfactionandexperience,andenhancenetworkflexibilityandadaptability.User-centricdeepcustomizationnetworksaimtoprovidehighlypersonalizedandcustomizednetworkservicesandexperiencesbasedontheneedsandpreferencesofdifferentapplicationscenariosandusergroups.Fromadeploymentperspective,intheuser-centricradioaccessnetwork,widelydeployednetworknodeswilldynamicallyconstructflexiblecellforeachuserbasedonpreciseuserneeds.Foreachuser,theflexiblecellisdeeplycustomizedinrealtime—anytime,anywhere,foranyservice,andanyusertype.User-centricradioaccessnetworksarewidelyapplicabletotoBandtoCnetworks.Fromthenetworkside,networknodescanbedeployedandreusedefficientlyandenergy-efficiently.Fromtheperspectiveofresourcesandapplications,thenetworkwillcustomizetheallocationandoptimizationofnetworkresourcesbasedonfactorssuchasuserlocation,devicetype,andnetworkqualitytoprovideoptimalperformanceanduserexperience.Forexample,thenetworkcanprovidecustomizedoptimizationandsupportbasedontheapplicationsandservicesusedbyusers.Forspecificapplicationscenarios(suchasonlinegamingandvideostreaming),thenetworkcanprovidespeciallyoptimizedbandwidth,latency,andotherservicestodeliverbetterapplicationperformance.Additionally,thenetworkcanmakeautonomousdecisionsandadjustmentsbasedonuserneedsandenvironmentalconditions.Forexample,basedonfactorssuchasuserpriorityandresourceutilization,thenetworkcanautomaticallyselecttheoptimalpath,allocatethemostsuitableresources,anddynamicallyadjustinrealtime.3.1.2ElasticReconfiguraTraditionalnetworkarchitecturesareoftenbasedonfixedtopologiesandstaticconfigurations.However,withthedevelopmentoftechnologiessuchascloudcomputing,IoT,and5G,userdemandsfornetworkshavebecomeincreasinglydiverseanddynamic.User-centricelasticreconfigurablenetworksaimtoprovideabetteruserexperienceandnetworkresourcemanagement.Theyachievethisbyadaptingtochangingdemandsandenvironments,supportingemergingapplicationscenariosandservicemodels(suchasedgecomputing,virtualreality,andIoT),therebyenhancingnetworkreliability,resilience,andefficiency.Differentfromthecellularnetworkthatisalwaysactivatedandwaitingforpotentialusers,theuser-centricradioaccessnetworkishighlyscalableandreconfigurable.Theycanautomaticallyadapttochangesinthenumberofusers,applicationrequirements,andnetworktopology.Forinstance,throughelasticreconfigurationanddynamicconfigurationofnetwork-sidenodes,suchasquantity,transmissionpower,andtransmissionmechanisms(e.g.,massiveMIMO),thenetworksidecanoptimallycontrolinterferenceandreducenetworkenergyconsumption.Apartfromconventionalcommunicationenvironments,user-centricradioaccessnetworkscanalsohandlesuddenadverseconditions,suchasnaturaldisasters.Theelasticreconfigurablenetworksupportstherobustnessandself-healingcapabilityofnetworkaccess.Thedesignandapplicationofflexiblecellcanpromotetheflexibilityofnetworkfacilitiesandachieverapidnetworkdeployment.Changeswithinacertainrangeofthenetworkwillnotdestroythenetwork'sabilitytomeetuserneeds.Networkresources(suchasbandwidth,storage,andcomputingcapabilities)canbevirtualizedandpooledtomoreflexiblyallocatethemtodifferentusersandapplications.Thenetworkcanmonitorandanalyzetheutilizationofnetworkresourcesinrealtime,sensechangesinuserdemandsbasedonreal-timenetworkstate,andadjustandreconfigurenetwork-sidenodesandresourcesautomaticallytoprovideoptimalnetworkservices.3.1.3OpennessandCompatibIntraditionalnetworkmodels,networksaretypicallyclosed,limitinginteroperabilitybetweenusersandothernetworksandservices.However,withtheaccelerationofnetworkdevelopmentanddigitaltransformation,thereisagrowingdemandforseamlessconnectionsandintegrationacrossnetworksandplatforms.User-centricopenandcompatiblenetworkswillapplytovarioustypesofnetwork-side