资源描述：
《中英论文翻译对照：全球移动通信系统》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。
1、GSM（GlobalSystemforMobileCommunication）Thesuccessofmobilesystemsacrosstheworldisasignthatcommunicationismovingtowardsamorepersonalized,convenientsystem.Peoplewhohavetouseamobilephoneonbusinesssoonbegintorealizethattheabilitytophoneanytime,anyplaceino
2、ne'spersonalliferapidlybecomesanecessity,notaconvenience.Thespeedandrapiditywithwhichthepersonalcommunicationsrevolutiontakesplaceis,unlikefixedtransmissionsystems,highlydependentontechnologyandcommunicationstandards.Formobilethethreekeyelementstoach
3、ievingservicetake-uparethecost,thesizeandtheweightofthephone,andthecostandqualityofthelink.3Ifanyofthesearewrong,especiallythefirsttwo,thenmarketgrowthisliabletobeseverelyrestricted.Thefixedtelephoneserviceisglobalandtheinterconnectionvariesfromcoaxi
4、alcabletoopticalfibreandsatellite.Thenationalstandardsaredifferent,butwithcommoninterfacesandinterfaceconversion,interconnectioncantakeplace.Formobiletheproblemisfarmorecomplex,withtheneedtoroamcreatinganeedforcomplexnetworksandsystems.Thusinmobileth
5、equestionofstandardsisfarmorecrucialtosuccessthanfixedsystems.4Inaddition,thereisalsothevexedquestionofspectrumallocationinthemobilearea. Mobilesystemsoriginallyoperatedinanalogmodeinthe450MHzband,movinglaterto900MHzwithdigitalGSMandthento1,800MHzwit
6、hpersonalcommunicationsystems.Thehistoryofmobilitycansplitintogenerations.Thefirstgenerationsystemsweretheadvancedmobilephonesystems(AMPS)intheUS,totalaccesscommunicationsystem(TACS)inmostofEuropeandNordicmobiletelephonesystem(NMT);whichwereallanalog
7、uesystems.ThesecondgenerationisvarymuchdominatedbythestandardfirstsetoutinEuropebythegroupspecialmobile(GSM)committee,whichwasdesignedasaglobalmobilecommunicationsystem.TheGSMsystemisbasedonacellularcommunicationsprinciplewhichwasfirstproposedasaconc
8、eptinthe1940sbyBellSystemengineersintheUS.Theideacameoutoftheneedtoincreasenetworkcapacityandgotroundthefactthatbroadcastmobilenetworks,operatingindenselypopulatedareas,couldbejammedbyaverysmallnumberofsimultaneouscalls.5Thepowerofthecellularsystemwa
