I基于MATLAB的OFDM系统仿真摘要由于无线电波传播特性复杂，在传播过程中遇到高楼、山峰产生饶射从而造成多径效应，这对于移动通信、广播通信等有着非常严重的影响。正交频分复用技术即OFDM（OrthogonaFrequencyDivisionMultiplexing）就提供了一个很好的解决方案。MATLAB是美国MathWorks公司出品的商业数学软件，MATLAB具有强大的计算能力，内置大量通信方面的函数，可以简便轻松地进行IDFT和DFT计算，并且操作界面友好便于学习。本文研究了OFDM技术的基本原理及其技术难点，OFDM是一种特殊的多载波调制技术其主要思想是将信道分成若干个正交子信道，将高速的串行数据信号转换成并行的低速子数据流，然后再调制到每个正交的子信道上进行传输，子信道的正交调制和解调可以通过离散傅里叶反变换IDFT和离散傅里叶变换DFT实现。OFDM技术的特点在于各子载波之间是相互正交的，利用子载波间的正交性可以提高频带利用率，再通过各子载波的联合编码可以有效地抗频率选择性衰落和快衰落，因此，OFDM技术也成为第四代移动通信技术中的核心技术之一。仿真部分对OFDM系统进行了简化，仅保留了OFDM系统基本组成部分，分别是串并转换、QPSK调制和解调、IDFT/DFT、保护间隔和信道噪声，并运用MATLAB软件编写程序对OFDM系统进行仿真，验证OFDM系统性能，对不同信噪比下的OFDM系统传输误码率进行了记录和分析。【关键词】正交频分复用MATLAB系统仿真--IIABSTRACTDuetothecomplexcharacteristicsofradiowavepropagation,thereisamulti-patheffectwhenencounteringtallbuildingsandpeaksinthepropagationprocess,whichhasaveryseriousimpactonmobilecommunicationandbroadcastingcommunication.OrthogonalFrequencyDivisionMultiplexing(OFDM)providesagoodsolution.MATLABisacommercialmathematicalsoftwareproducedbyMathWorksoftheUnitedStates.MATLABhaspowerfulcomputingpowerandalargenumberofbuilt-incommunicationfunctions.ItiseasytocalculateIDFTandDFT,andhasafriendlyinterfaceforlearning.ThispaperstudiesthebasicprincipleofOFDMtechnologyanditstechnicaldifficulties,OFDMisaspecialkindofmulti-carriermodulationtechnology,itsmainideaistochannelintoseveralisjiaozi,channel,thehigh-speedserialdatasignalintoaparallellowspeeddataflow,andthentoeachorthogonalmodulationtransmissiononsub-channels,orthogonalmodulationanddemodulationofsub-channelsbydiscreteinversediscreteFouriertransform(IDFT)anddiscreteFouriertransform(DFT).ThecharacteristicofOFDMtechnologyisthateachsubcarrierisorthogonaltoeachother.Theorthogonalitybetweensubcarrierscanimprovethefrequencybandutilization,andthejointcodingofeachsubcarriercaneffectivelyresistfrequencyselectivefadingandfastfading.Therefore,OFDMtechnologyhasbecomeoneofthecoretechnologiesinthefourthgenerationmobilecommunicationtechnology.SimulationpartofOFDMsystemsissimplified,retainonlythebasicpartofOFDMsystem,stringandtransform,QPSKmodulationanddemodulation,DFT/IDFT,protectionintervalandchannelnoise,andusingMATLABsoftwareprogramming,theOFDMsystem,simulationoftheOFDMsystemunderdifferentsignal-to-noiseratiotransmissionbiterrorrateisrecordedandanalyzed.【Keywords】OFDMMATLABSystemsimulation--III目录前言....................................................................................................................................................1第一章OFDM概述............................................................................................................................2第一节OFDM的发展历史............................................................................................................2第二节OFDM的应用..............................................................................................
