2013年设计-温湿度检测设计-(外文)翻译

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1、广西科技大学GuangxiUniversityofScienceandTechnology毕业设计（论文）外文翻译外文题目GSM移动通信系统综述院(系)计算机学院专业通信工程班级学号200900402022姓名指导教师2013年5月20日广西科技大学原文：OverviewoftheGlobalSystemforMobileCommunicationsHistoryofGSM：Duringtheearly1980s,analogcellulartelephonesystemswereexperiencingrapidgrowthinEurope,particularlyin

2、ScandinaviaandtheUnitedKingdom,butalsoinFranceandGermany.Eachcountrydevelopeditsownsystem,whichwasincomepaiblewitheveryoneelse'sinequipmentandoperation（Intermsofequipmentandoperationandothercountriesarenotidentical）.Thiswasanundesirablesitution,becausenotonlywasthemobileequipmentlimitedto

3、operationwithinnationalboundaries,whichinaunifiedEuropewereincreasinglyunimportant,buttherewasalsoaverylimitedmarketforeachtypeofequipment,soeconomiesofscaleandthesubsequentsavingscouldnotberealized.TheEuropeansrealizedthisearlyon,andin1982theConferenceofEuropeanPostsandTelegraphs(CEPT)fo

4、rmedastudygroupcalledtheGroupeSpecialMobile(GSM)tostudyanddevelopapan-Europeanpubliclandmobilesystem.Theproposedsystemhadtomeetcertaincriteria:lGoodsubjectivespeechqualitylLowterminalandservicecostlSupportforinternationalroaminglAbilitytosupporthandheldterminalslSupportforrangeofnewservic

5、esandfacilitieslSpectralefficiencylISDNcompatibilityIn1989,GSMresponsibilitywastransferredtotheEuropeaTelecommunicationStandardsInstitute(ETSI),andphaseIoftheGSMspecificationswerepublishedin1990.Commercialservicewasstartedinmid-1991,andby1993therewere36GSMnetworksin22countries.Althoughsta

6、ndardizedinEurope,GSMisnotonlyaEuropeanstandard.Over200GSMnetworks(includingDCS1800andPCS1900)areoperationalin110countriesaroundtheworld.Inthebeginningof1994,therewere1.3millionsubscribersworldwidewhichhadgrowntomorethan55millionbyOctober1997.WithNorthAmericamakingadelayedentryintotheGSMf

7、ieldwithderivativeofGSMcalledPCS1900,GSMsystemsexistoneverycontinent,andtheacronymGSMnowaptlystandsforGlobalSystemfor16广西科技大学Mobilecommunications.ThedevelopersofGSMchoseanunproven(atthetime)digitalsystem,asopposedtothethen-standardanalogcellularsystemslikeAMPSintheU