资源描述：
《通信工程专业外语-unit13原文与翻译.doc》由会员上传分享，免费在线阅读，更多相关内容在应用文档-天天文库。
1、Unit13ComparisonbetweenGSMandCDMAGSM与CDMA之比较UsingCDMA/FDDtechnology,subscribersofCDMAcellularmobilecommunicationsystemcantransmittheirinformationsimultaneouslythroughthesamechannel.Ontheotherhand,theGSMsystemadoptsTDMA/FDDmethodtotransmitanddistinguishinformationfr
2、omdifferentGSMmobilestations.Inaddition,infavorofQCELParithmetic,RAKEreceiver,powercontrolandsoftswitchingetc.,CDMAshowsmoreadvantagesinitssystemperformancethantheGSM,suchasgreateranti-interferencecapability,biggersystemcapacity,highersuccessfulconnectionratio,fewe
3、roff-linechances,lowprobabilityofintercept(LPI),andsoon.使用码分多址/频分双工技术，用户的蜂窝移动通信系统的传输信息的同时，通过同样的渠道。另一方面，该系统采用时分多址/频分双工传输的方法和识别信息从不同的移动台。此外，有利于中国电信集团广州研发中心算术，耙式接收器，功率控制和软开关等，显示出更多的优势在码分多址系统性能比，如更高的抗干扰能力，更大的系统容量，连接成功率较高，离线的机会少，低截获概率（低截获概率），等。1,PowerControlandRAKERecei
4、ver功率控制和瑞克接收机WhendifferentsubscriberssendtheirinformationtothesameBS(basestation),differentsignalpowercausedbydifferenttransmittingdistanceswillconsequentiallycauseinterferencewitheachother,especiallyforthoseMSs(mobilestation)beingfarawayfromBSwillbeseriouslydistur
5、bedbecauseoftheiralmostsubmergedsignalsbysignalsoftheclose-to-BSMSs.[2]p110Inordertosolvethisproblemandkeephighsystemperformance,powercontroltechniqueisintroducedinCDMAcommunicationsystem,whichcaneffectivelyovercomethiscross-disturbance.AsoneofthecoretechniquesinCD
6、MAcellularmobilecommunicationsystem,powercontrolcanmakethesignalpowerfromallsubscriberstotheBSequivalentthroughadjustingthetransmittingpowerfromeachsubscriber.为解决这一问题，保持较高的系统性能，功率控制技术介绍了码分多址通信系统，它可以有效地克服这cross-disturbance。作为一个核心技术在蜂窝移动通信系统的功率控制，可以使信号功率从所有用户的学士学位相当于
7、通过调整发射功率，从每个用户。Powercontrolcanbenotonlydividedtoopen-loopcontrolandclosed-loopcontrol,butalsotoforward(down)powercontrolandbackward(up)powercontrol.Foropen-loopcontrolmethod,subscriberadjustsemittingpoweraccordingtothemeasuredframeerrorprobability,whilefortheclosed
8、-looppowercontrol,basestationmeasuresthesignal-to-noiseratioofreceivedsignalsandthenadjustthetransmittingpowerofcorrespondingMS.功率控制不仅可以分为开环控制和闭环
