全球移动通信系统概要中英文

Overview of the Global System for Mobile Communications1 History of GSMDuring the early 1980s, analo

OverviewoftheGlobalSystemforMobileCommunications 1HistoryofGSM Duringtheearly1980s,analogcellulartelephonesystemswere experiencingrapidgrowthinEurope,particularlyinScandinaviaandtheUnited Kingdom,butalsoinFranceandGermany.Eachcountrydevelopeditsown system,whichwasincompatiblewitheveryoneelse’sinequipmentand operation.Thiswasanundesirablesituation,becausenotonlywasthemobile equipmentlimitedtooperationwithinnationalboundaries,whichinaunified Europewereincreasinglyunimportant,buttherewasalsoaverylimitedmarket foreachtypeofequipment,soeconomiesofscaleandthesubsequentsavings couldnotberealized. TheEuropeansrealizedthisearlyon,andin1982theConferenceof EuropeansPostsandTelegraphs(CEPT)formedastudygroupcalledtheGroup SpecialMobile(GSM)tostudyanddevelopapan-Europeanpubliclandmobile system.Theproposedsystemhastomeetcertaincriteria: ·Goodsubjectivespeechquality ·Lowterminalandservicecost ·Supportforinternationalroaming ·Abilitytosupporthandheldterminals ·Supportforrangeofnewservicesandfacilities ·Spectralefficiency ·ISDNcompatibility In1989,GSMresponsibilitywastransferredtotheEuropean TelecommunicationStandardsInstitute(ETSI),andphaseIoftheGSM specificationswerepublishedin1990.Commercialservicewasstartedin mid-1991,andby1993therewere36GSMnetworksin22countries.Although standardizedinEurope,GSMisnotonlyaEuropeanstandard.Over200GSM networksareoperationalin110countriesaroundtheworld.Inthebeginningof 1994,therewere1.3millionsubscribersworldwide,whichhadgrowntomore than55millionbyOctober1997.WithNorthAmericamakingadelayedentry intotheGSMfieldwithaderivativeofGSMcalledPCS1900,GSMsystems existoneverycontinent,andtheacronymGSMnowaptlystandsforGlobal SystemforMobilecommunications. ThedevelopersofGSMchoseanunproven(atthetime)digitalsystem,as opposedtothethen-standardanalogcellularsystemslikeAMPSintheUnited