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1、桂林电子科技大学毕业设计（论文）原文用纸第9页共9页毕业设计(论文)英文翻译原文院（系）：桂林航天工业高等专科学校专业：计算机通信工程学生姓名：胡文凯学号：030111301497指导教师：嵇建波职称：副教授2012年4月15日桂林电子科技大学毕业设计（论文）原文用纸第9页共9页Chapter1ModernmobilecommunicationtechnologyInnowhighlytheinformationizationsociety,theinformationandthecorrespondencehavebecomethemode
2、rnsociety“thelife”.Theinformationexchangemainlyreliesonthecomputercorrespondence,butcorrespondstakesthetransmissionmethod,withthesensingtechnology,thecomputertechnologyfusesmutually,hasbecomeinthe21stcenturytheinternationalsocietyandtheworldeconomicdevelopmentpowerfulengine
3、.Inordertoofadaptthetimerequest,thenewgenerationofmobilecommunicationtechnologyseasonableandlives,thenewgenerationofmobilecommunicationtechnologyisthepeoplesaidthatthirdgeneration'scorecharacteristicisthewidebandaddressingturnsonnon-gaproamingbetweentherigidnetworkandnumero
4、usdifferentcommunicationssystem's,gainsthemultimediacommunicationservices.Alongwiththetimeprogress,thetechnicalinnovation,people'sliferequest'senhancement,themobilecommunicationtechnologyrenewalspeedisquiteastonishing,almosteveryothertenyearmobilecommunicationtechnologyhasa
5、transformationupdate,fromthe1980s“themobilephone”topresent's3Ghandset,duringhashadtwomobilecommunicationtechnologytransformation,transitsfrom1GAMPSto2GGSM,fromGSMtoIMT-2000(i.e.3Gtechnology).Knowsmodernonmethemobilecommunicationtechnologytohavethefollowingseveralaspectimpor
6、tanttechnology:1.widebandmodulationandmultipleaccesstechniqueThewirelesshighspeeddatatransmissioncannotonlydependonthefrequencyspectrumconstantlytheexpansion,shouldbehigherthanthepresentnumbermagnitudeatleastinthefrequencyspectrumefficiency,mayusethreetechnologiesinthephysi
7、callevel,namelyOFDM,UWBandfreetimemodulationcode.OFDMwithotherencodingmethod'sunion,nimblyOFDMandTDMA,FDMA,CDMA,SDMAcombinesthemultipleaccesstechnique.Inthe1960stheOFDMmulti-channeldatatransmissionhassucceededusesinKineplexandtheKathrynhighfrequencymilitarychannels.OFDMhasu
8、sedin1.6Mbit/shighbitratedigitalsubscriberline(HDSL),6Mbit/sasymmetricaldigitalsub
