资源描述：
《通信工程专业英语结课论文(中英).doc》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。
1、ModernmobilecommunicationtechnologyInnowhighlytheinformationizationsociety,theinformationandthecorrespondencehavebecomethemodernsociety“thelife”.Theinformationexchangemainlyreliesonthecomputercorrespondence,butcorrespondstakesthetransmissionmethod,withthesensingtechnology,thecomputertechn
2、ologyfusesmutually,hasbecomeinthe21stcenturytheinternationalsocietyandtheworldeconomicdevelopmentpowerfulengine.Inordertoofadaptthetimerequest,thenewgenerationofmobilecommunicationtechnologyseasonableandlives,thenewgenerationofmobilecommunicationtechnologyisthepeoplesaidthatthirdgeneratio
3、n'scorecharacteristicisthewidebandaddressingturnsonnon-gaproamingbetweentherigidnetworkandnumerousdifferentcommunicationssystem's,gainsthemultimediacommunicationservices.themobilecommunicationtechnologytohavethefollowingseveralaspectimportanttechnology:1.widebandmodulationandmultipleacces
4、stechniqueThewirelesshighspeeddatatransmissioncannotonlydependonthefrequencyspectrumconstantlytheexpansion,shouldbehigherthanthepresentnumbermagnitudeatleastinthefrequencyspectrumefficiency,mayusethreetechnologiesinthephysicallevel,namelyOFDM,UWBandfreetimemodulationcode.OFDMwithotherenco
5、dingmethod'sunion,nimblyOFDMandTDMA,FDMA,CDMA,SDMAcombinesthemultipleaccesstechnique.Inthe1960stheOFDMmulti-channeldatatransmissionhassucceededusesinKineplexandtheKathrynhighfrequencymilitarychannels.OFDMhasusedin1.6Mbit/shighbitratedigitalsubscriberline(HDSL),6Mbit/sasymmetricaldigitalsu
6、bscriberline(ADSL),100Mbit/sreallyhighspeedfiguresubscriber'sline(VDSL),digitalaudiofrequencybroadcastanddigitalvideobroadcastandsoon.OFDMapplieson5GHzprovides54Mbit/swireless8localnetworkIEEE802.11aandIEEE802.11g,highperformancethisregionnetworkHiperLAN/2andETSI-BRAN,butalsotakesmetropol
7、itanareanetworkIEEE802.16andtheintegratedservicedigitbroadcast(ISDB-T)thestandard.Compareswiththesingleloadfrequencymodulationsystemservicepattern,theOFDMmodulationservicepatternneedstosolvetherelativelybigpeakevenpowerratio(PAPR,PeaktoAveragePowerRatio)andtothefreq
