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1、河南理工大学万方科技学院本科毕业论文外文资料与中文翻译外文资料：ReviewofUMTS1.1UMTSNetworkArchitectureTheEuropean/Japanese3GstandardisreferredtoasUMTS.UMTSisoneofanumberofstandardsratifiedbytheITU-TundertheumbrellaofIMT-2000.Itiscurrentlythedominantstandard,withtheUSCDMA2000standardgainingground,p
2、articularlywithoperatorsthathavedeployedcdmaOneastheir2Gtechnology.Attimeofwriting,Japanisthemostadvancedintermsof3Gnetworkdeployment.Thethreeincumbentoperatorstherehaveimplementedthreedifferenttechnologies:J-PhoneisusingUMTS,KDDIhasaCDMA2000network,andthelargestope
3、ratorNTTDoCoMoisusingasystembrandedasFOMA(FreedomofMultimediaAccess).FOMAisbasedontheoriginalUMTSproposal,priortoitsharmonizationandstandardization.TheUMTSstandardisspecifiedasamigrationfromthesecondgenerationGSMstandardtoUMTSviatheGeneralPacketRadioSystem(GPRS)andE
4、nhancedDataforGlobalEvolution(EDGE),asshowninFigure.ThisisasoundrationalesinceasofApril2003,therewereover847MillionGSMsubscribersworldwide1,accountingfor68%oftheglobalcellularsubscriberfigures.TheemphasisisonkeepingasmuchoftheGSMnetworkaspossibletooperatewiththenews
5、ystem.WearenowwellontheroadtowardsThirdGeneration(3G),wherethenetworkwillsupportalltraffictypes:voice,videoanddata,andweshouldseeaneventualexplosionintheservicesavailableonthemobiledevice.ThedrivingtechnologyforthisistheIPprotocol.Manycellularoperatorsarenowataposit
6、ionreferredtoas2.5G,withthedeploymentofGPRS,whichintroducesanIPbackboneintothemobilecorenetwork.Thediagrambelow,Figure2,showsanoverviewofthekeycomponentsinaGPRSnetwork,andhowitfitsintotheexistingGSMinfrastructure.TheinterfacebetweentheSGSNandGGSNisknownastheGninterf
7、aceandusestheGPRStunnelingprotocol(GTP,discussedlater).Theprimaryreasonfortheintroductionofthisinfrastructureistoofferconnectionstoexternalpacketnetworks,suchastheInternetoracorporateIntranet.ThisbringstheIPprotocolintothenetworkasatransportbetweentheSGSNandGGSN.Thi
8、sallowsdataservicessuchasemailorwebbrowsingonthemobiledevice,withusersbeingchargedbasedonvolumeofdataratherthantimeconnected.15河南理工大学万方科技学
