在IMS系统中集成不同无线接入网络-101P-EN-200810

wererer

NextgenerationheterogeneouswirelessnetworksareexpectedtointerworkwithInternetProtocol
(IP)-basedinfrastructures.Conventionalnetworkservicesoperatelikesilosinthataspecicset
ofservicesareoeredoveraspecictypeofaccessnetwork.Asaccessnetworksevolvetoprovide
IP-basedpacketaccess,itbecomesattractivetobreaktheseservicesilosbyoeringaconverged
setofIP-basedservicestouserswhomayaccesstheseservicesusinganumberofalternative
accessnetworks.Thistrendhasstartedwiththirdgenerationcellularmobilenetworks,which
havestandardizedontheuseoftheIPMultimediaSubsystem(IMS)tomanageuseraccessto
awidevarietyofmultimediaservicesoverthemobileInternet,whilefacilitatinginterworkingof
heterogeneouswirelessandlandlineaccessnetworks.
ThefutureusersofcommunicationsystemswillsubscribetobothIP-basedandCircuitSwitched
(CS)basedservicesandintheforeseeablefutureasingledatabasethathandlesuserprolesacross
alldomainswillberequired.HomeSubscriberServer(HSS)asanevolvedversionofHomeLocation
Register(HLR)isoneofthekeycomponentsofIMS.IndeployingHSSasacentralrepository
database,inafullyoverlappedheterogeneousnetworksetting,changesofaccessmodearevery
frequentandconveyingthisinformationtoHSSimposesexcessivesignalingloadanddelay.In
ourproposedschemeweintroduceanInterfaceAgent(IA)foreachlocationareathatcachesthe
locationandinformationabouttheaccessmodethroughwhichausercanbereached.Thismethod
resultsinsignicantamountofsavingsinsignalingcostandbetterdelayperformance.
Theexistingcalldeliveryapproachesincellularnetworksmaynotbewellsuitedforfuture
communicationsystemsbecausetheysuerfromunnecessaryusageofnetworkresourcesforcall
attemptsthatmayfailwhichaddstoexcessivesignalingdelaysandqueuingcosts.Reducingthe
numberofqueriesandretrievalsfromthedatabasewillhaveasignicantimpactonthenetwork
performance.WepresentanewschemebasedonReverseVirtualCallsetup(RVC)asasolution
tothecalldeliveryprobleminheterogeneouswirelessnetworksandevaluatetheperformanceof
thisframework.