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题目：4G移动通信系统中的空间分集技术2013年6月2013届本科毕业设计论文I摘要移动通信技术已经成为当今通信领域发展最快、市场潜力最大的热点技术。第四代移动通信系统——4G可以提供在不同的固定、无线平台和跨越不同的频带的网络中提供无线服务，可以在任何地方宽带接入互联网，能够提供信息通信之外的定位定时、数据采集、远程控制等综合功能。4G的通信网络特点是宽带化、自组织化、移动化和全IP化等，为满足4G移动通信系统的高传输速率和宽带覆盖范围的要求，MIMO（多入多出通信系统）技术已经成为其关键技术之一。MIMO通信系统具有良好的发展前景，其发展是惊人的，大量的研究和丰硕成果迅速出现。空间分集技术是MIMO的基本入门技术。本文通过对空间分集技术的研究背景和无线信道的衰落特征做了简要介绍，对空间分集技术中分集技术和合并技术作了比较详细分类与研究，重点对最大比值合并、等增益合并、选择式合并技术做了详细的推论与对比，并进行了性能仿真研究，对比三种合并方式的性能；对Alamouti发射分集方案进行性能分析并仿真，对最大合并比方案与Alamouti发射分集方案进行性能比较分析，通过仿真对比其性能。最后对空间分集的发展提出展望，最终达到了本文的实证价值和研究意义。关键词：4G；MIMO；空间分集；Alamouti方案2013届本科毕业设计论文IIABSTRACTMobilecommunicationtechnologyhasbecomethefastestgrowingandthelargestmarketpotentialinthefieldofcommunication.TheFourthgeneration--4Gmobilecommunicationsystemcanprovidethedifferentfixedandwirelessplatformsandacrossdifferentfrequencybandsforwirelessserviceinthenetwork,canbeinanyplaceofbroadbandInternetaccess,canprovidepositioningtimeoutsideofinformationcommunication,dataacquisition,remotecontrol,andcomprehensivefunctions.4Gcommunicationsnetworkischaracterizedbybroadbandnetworks,selforganized,mobileandallIP,etc.,tomeetthehightransmissionrateof4Gmobilecommunicationsystemandbroadbandcoveragerequirement,MIMO(Multiple-InputMultiple-Out-put)hasbecomeoneofthekeytechnologies.MIMOcommunicationsystemhasgoodprospectsfordevelopment,itsdevelopmentisastonishing,alotofresearchandfruitfulresultsquickly.SpacediversitytechnologyisintroductiontothebasicofMIMOtechnology.Inthispaper,throughthestudyofspacediversitytechnologybackgroundanddoabriefintroductionofthefadingcharacteristicsofwirelesschannel,diversityofspacediversitytechnologyiscomparedwithtechnologyandcombinetechnology,detailedclassificationandresearchfocusofmaximalratiocombining,gain,choosethecombiningtechnologysuchasinferenceandcontrastindetail,andtheperformancesimulation,comparedtheperformanceofthethreekindsofcombinationway;OnAlamoutitransmitdiversityschemeforperformanceanalysisandsimulation,thelargestmergerthanwithAlamoutischemetransmitdiversityschemeforperformancecomparisonanalysis,compareditsperformancethroughsimulation.Finallyputforwardoutlookonthedevelopmentofspacediversity,andeventuallyreachedtheempiricalvalueandresearchsignificanceofthispaper.Keywords:4G；MIMO；SpatialDiversity；AlamoutiScheme2013届本科毕业设计论文III目录第一章绪论..............................................................11.1课题背景............................................................................................................................................11.2空间分集技术的发展....................................................................................................................21.3本文研究内容与章节安排............................................................................................................2第二章多天线技术......................................................42.1多天线技术研究背景..........................................................42.1.1传统天线向多天线技术的发展.....................................42.1.2智能天线向多天线的发展.........................................52.2多天线技术基本原理..........................................................6第三章空间分集技术...................................................83.1分集技术的概念..............................................................83.2分集技术的分类..............................................................83.2.1空间分集.......................................................93.2.2频率分集.......................................................93.2.3角度分集.......................................................93.2.4极化分集.......................................................93.2.5时间分集......................................................103.3空间分集技术原理...........................................................103.4分集接收技术...............................................................113.4.1选择式合并(SC)................................................123.4.2最大比值合并（MRC）...........................................123.4.3等增益合并（EGC）.............................................132013届本科毕业设计论文IV3.5分集合并性能的分析与比较..................................................133.5.1选择式合并的性能..............................................133.5.2最大比值合并的性能............................................153.5.3等增益合并的性能..............................................163.5.4多重分集系统平均误码率考虑....................................163.6Alamouti发射分集方案.....................................................183.6.1Alamouti方案的编码原理.......................................183.6.2合并和最大似然译码............................................203.6.3多根接收天线的Alamouti方案...................................213.6.4Alamouti方案的性能...........................................223.7空间分集性能比较....................................................243.7.1经典最大比接收合成(MRC)方案..................................243.7.2多个接收机双分支发射分集......................................26第四章仿真实现与结果分析...........................................294.1MATLAB简介.........................................................294.1.1MATLAB语言及特点............................................294.1.2M文件介绍....................................................294.1.3MATLAB基本绘图方法.