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1、毕业设计(论文)分析与仿真OFDM系统的同步系别通信工程系专业通信工程班级40407班姓名都海峰指导教师年月日OFDM系统的同步技术分析与仿真摘要正交频分复用(OFDM)技术是当前移动通信领域的一项关键技术,它具有很强的抗符号间干扰、抗多径衰落的能力,适合在无线信道中传输高速的数据业务,因而倍受关注。OFDM采用了正交载波技术,频谱利用率很高。目前已被应用于无线局域网、数字音频广播、数字视频广播系统中,并且有望成为第四代移动通信系统的核心技术。本文首先概述了OFDM的原理、特征和关键技术,介绍了系统需要的几种同步。然后
2、就同步误差对系统性能的影响进行了简单的分析,表明定时偏差和采样频率偏差将会引入码间干扰,载波频率偏差导致载波间干扰的发生。因此,在OFDM系统接收机中定时的确定、载波频率偏差和采样频率偏差的纠正是信号恢复的关键。之后对OFDM系统同步的几种实现方法进行了介绍,分析了各同步方法的性能。最后本文重点对OFDM系统进行了仿真,设计了OFDM系统的仿真模型,编写了OFDM系统的matlab程序,对信号传输各个时期的波形进行了分析,并通过改变信道信噪比分析了系统对抗多径衰落的能力。关键词:OFDM,载波偏差,定时偏差Analys
3、isandSimulationonOFDMSynchronizationTechnologyAuthor:GuoHaifengTutor:HuangLiqunAbstractOrthogonalFrequencyDivisionMultiplexingisoneofkeytechnologiesinmobilecommunicationfields;itissuitableforhighratedatatransmissioninwirelesschannelsbecauseitcancombatInter-Symbo
4、lInterferenceandmulti-pathfadingefficiently,nowithasbecomeanattractivetechnology.OFDMisamultiplecarrierstechnology,supportshighratedatatransmissionwithhighspectrumefficiency.Atpresent,OFDMtechnologyhasbeenusedinmanyfields,suchaswirelesslocalnetwork,digitalaudiob
5、roadcasting,anddigitalvideobroadcastingsystemsandsoon.Itisverypromisingtobeacoretechnologyofthefourthgenerationmobilecommunications.Atfirst,theprinciple,propertiesandkeytechnologyaredescribedsimply,severalsynchronizationinneedforthesystemareintroduced.Theeffecto
6、fsynchronizationerrorofanOFDMsystemisdiscussedindetail.Thestudyshowthatsymboltimingoffsetandsamplingfrequencyoffsetwouldintroduceinter-symbolinterference,frequencyoffsetofcarrierswouldresultininter-carrierinterference.So,inanOFDMsystem,findingthesymboltiming,the
7、carrierfrequencyoffset,andthesamplingrateoffsetatthereceiverisimportantintherecoveryofthesignal.FinallythispaperonOFDMsystemforthesimulation,designedOFDMsystemsimulationmodeldevelopedOFDMsystemmatlabprocedures,thevariousperiodsofsignaltransmissionwaveformwereana
8、lyzed,andbychangingthechannelsignaltonoiseratioofthesystemagainstmulti-pathTheabilityofthedecline.KeyWords:OrthogonalFrequencyDivisionMultiplexing,Carrierfrequencyoff