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1、附录4****大学本科毕业设计（论文）外文翻译课题名称：基于MATLAB的TD-SCDMA通信系统的调制与解调仿真程序设计学院（系）：信息科学与工程学院年级专业：***级通信工程3班学生姓名：指导教师：完成日期：20**年3月26日附录4ReviewofUMTS1.1UMTSNetworkArchitectureTheEuropean/Japanese3GstandardisreferredtoasUMTS.UMTSisoneofanumberofstandardsratifiedbytheITU-TundertheumbrellaofIMT-2000.Itiscurrentlythedom
2、inantstandard,withtheUSCDMA2000standardgainingground,particularlywithoperatorsthathavedeployedcdmaOneastheir2Gtechnology.Attimeofwriting,Japanisthemostadvancedintermsof3Gnetworkdeployment.Thethreeincumbentoperatorstherehaveimplementedthreedifferenttechnologies:J-PhoneisusingUMTS,KDDIhasaCDMA2000net
3、work,andthelargestoperatorNTTDoCoMoisusingasystembrandedasFOMA(FreedomofMultimediaAccess).FOMAisbasedontheoriginalUMTSproposal,priortoitsharmonizationandstandardization.TheUMTSstandardisspecifiedasamigrationfromthesecondgenerationGSMstandardtoUMTSviatheGeneralPacketRadioSystem(GPRS)andEnhancedDataf
4、orGlobalEvolution(EDGE),asshowninFigure.ThisisasoundrationalesinceasofApril2003,therewereover847MillionGSMsubscribersworldwide1,accountingfor68%oftheglobalcellularsubscriberfigures.TheemphasisisonkeepingasmuchoftheGSMnetworkaspossibletooperatewiththenewsystem.WearenowwellontheroadtowardsThirdGenera
5、tion(3G),wherethenetworkwillsupportalltraffictypes:voice,videoanddata,andweshouldseeaneventualexplosionintheservicesavailableonthemobiledevice.ThedrivingtechnologyforthisistheIPprotocol.Manycellularoperatorsarenowatapositionreferredtoas2.5G,withthedeploymentofGPRS,whichintroducesanIPbackboneintothe
6、mobilecorenetwork.Thediagrambelow,Figure2,showsanoverviewofthekeycomponentsinaGPRSnetwork,andhowitfitsintotheexistingGSMinfrastructure.TheinterfacebetweentheSGSNandGGSNisknownastheGninterface附录4andusestheGPRStunnelingprotocol(GTP,discussedlater).Theprimaryreasonfortheintroductionofthisinfrastructur
7、eistoofferconnectionstoexternalpacketnetworks,suchastheInternetoracorporateIntranet.ThisbringstheIPprotocolintothenetworkasatransportbetweentheSGSNandGGSN.Thisallowsdataservicessuchasemailorwebbrowsingonthe
