刘亚圣 蜂窝无线通信系统的研究英文翻译

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1、蜂窝无线系统的研究专业班级：信息工程07-1班姓名：耿永鹏学好：200707070111河南科技大学本科毕业设计（论文）——英文翻译题目蜂窝无线通信系统的研究学生姓名刘亚圣专业班级电子信息工程092班学号09104020213院（系）电子信息工程学院指导教师（职称）完成时间2012年3月28日7蜂窝无线系统的研究专业班级：信息工程07-1班姓名：耿永鹏学好：200707070111英文原文RESEARCHOFCELLULARWIRELESSCOMMUNICATIONSYSTEMAbstractCellularcommunicationsystemsallowalar

2、genumberofmobileuserstoseamlesslyandsimultaneouslycommunicatetowirelessmodemsatfixedbasestationsusingalimitedamountofradiofrequency(RF)spectrum.TheRFtransmissionsreceivedatthebasestationsfromeachmobilearetranslatedtobaseband,ortoawidebandmicrowavelink,andrelayedtomobileswitchingcenters

3、(MSC),whichconnectthemobiletransmissionswiththePublicSwitchedTelephoneNetwork(PSTN).Similarly,communicationsfromthePSTNaresenttothebasestation,wheretheyaretransmittedtothemobile.Cellularsystemsemployeitherfrequencydivisionmultipleaccess(FDMA),timedivisionmultipleaccess(TDMA),codedivisi

4、onmultipleaccess(CDMA),orspatialdivisionmultipleaccess(SDMA).1IntroductionAwidevarietyofwirelesscommunicationsystemshavebeendevelopedtoprovideaccesstothecommunicationsinfrastructureformobileorfixedusersinamyriadofoperatingenvironments.Mostoftoday’swirelesssystemsarebasedonthecellularra

5、dioconcept.Cellularcommunicationsystemsallowalargenumberofmobileuserstoseamlesslyandsimultaneouslycommunicatetowirelessmodemsatfixedbasestationsusingalimitedamountofradiofrequency(RF)spectrum.TheRFtransmissionsreceivedatthebasestationsfromeachmobilearetranslatedtobaseband,ortoawideband

6、microwavelink,andrelayedtomobileswitchingcenters(MSC),whichconnectthemobiletransmissionswiththePublicSwitchedTelephoneNetwork(PSTN).Similarly,communicationsfromthePSTNaresenttothebasestation,wheretheyaretransmittedtothemobile.Cellularsystemsemployeitherfrequencydivisionmultipleaccess(F

7、DMA),timedivisionmultipleaccess(TDMA),codedivisionmultipleaccess(CDMA),orspatialdivisionmultipleaccess(SDMA).Wirelesscommunicationlinksexperiencehostilephysicalchannelcharacteristics,suchastime-varyingmultipathandshadowingduetolargeobjectsinthepropagationpath.7蜂窝无线系统的研究专业班级：信息工程07-1班