1基于MATLAB实现OFDM系统的解码摘要自80年代,数字移动通信技术逐渐开始成熟,并开始应用在各式各样的，种类不同的无线通信系统，例如，数字集群电话，数字蜂窝电话，无线寻呼等，以上使用的是特高频/甚高频波段的数字移动通信。但是这两者的移动信道存在很多问题，噪声干扰，在多径传播时易造成码间串扰，选择性衰弱等。为解决这些问题，又出现了一种更好的，更高效的调制方式，就是（正交频分复用）OFDM。它是第四代移动通信技术的关键、核心技术，也被广泛应用在移动通信的领域。它不仅信道利用率比较高，而且抗衰弱能力良好。正交频分复用(OFDM)发送的信号用码元周期为T的不归零方波作为其基带码型，并由一组正交的正弦信号作为其副载波调制而成的。OFDM的信号产生与解调的过程就是IDFT/DFT的变换过程。正交频分复用（OFDM）是一种调制技术，在许多新兴的宽带无线和有线通信系统中得到了广泛应用。由于OFDM技术具有利用多个频谱重叠的低速副载波传输高速数据流的能力，因此它具有频谱效率高、抗载波间和符号间抗干扰性、对服务器信道条件的适应性等优点，近年来，OFDM技术的研究越来越深入。基于OFDM传输技术，被认为是未来超高速光传输的一种有前途的技术。它可以构建一种在频谱分配和数据速率调节方面具有极大灵活性和可扩展性的新型弹性光网络结构，以支持未来多种业务和互联网流量的快速增长。关键字：正道频分复用、OFDM、调制方式2DecodingofOFDMSystemBasedonMATLABAbstractSincethe1980s,digitalmobilecommunicationtechnologyhasgraduallymatured,andbegantobeusedinavarietyofdifferenttypesofwirelesscommunicationsystems,suchasdigitaltrunkingtelephone,digitalcellularphone,wirelesspaging,etc.TheaboveusesdigitalmobilecommunicationinUHF/VHFband.However,therearemanyproblemsinbothmobilechannels,suchasnoiseinterference,intersymbolinterferenceandselectivefadinginmultipathpropagation.Inordertosolvetheseproblems,abetterandmoreefficientmodulationmethodhasemerged,namely(orthogonalfrequencydivisionmultiplexing)OFDM.Itisthekeyandcoretechnologyofthefourthgenerationmobilecommunicationtechnology.Itisalsowidelyusedinthefieldofmobilecommunication.Itnotonlyhashighchannelutilization,butalsohasgoodanti-fadingability.OrthogonalFrequencyDivisionMultiplexing(OFDM)signalsaremodulatedbyasetoforthogonalsinusoidalsignalsastheirsubcarriers,usingthenon-returnzerosquarewavewiththesymbolperiodTasitsbasebandcodetype.TheprocessofsignalgenerationanddemodulationinOFDMisthetransformationprocessofIDFT/DFT.OrthogonalFrequencyDivisionMultiplexing(OFDM)isamodulationtechnology,whichhasbeenwidelyusedinmanyemergingbroadbandwirelessandwiredcommunicationsystems.BecauseOFDMtechnologyhastheabilitytotransmithigh-speeddatastreamsusinglow-speedsubcarrierswithoverlappingspectrum,ithastheadvantagesofhighspectralefficiency,anti-interferencebetweencarriersandsymbols,andadaptabilitytoserverchannelconditions.Inrecentyears,theresearchofOFDMtechnologyhasbecomemoreandmorein-depth.BasedonOFDMtransmissiontechnology,itisconsideredasapromisingtechnologyforultra-high-speedopticaltransmissioninthefuture.Itcanconstructanewelasticopticalnetworkstructurewithgreatflexibilityandscalabilityinspectrumallocationanddatarateregulationto3supporttherapidgrowthofvariousservicesandInternettrafficinthefuture.Keywords:channelfrequencydivisionmultiplexing,OFDM目录第一章绪论................................................................................................................41.1OFDM的研究背景、意义...............................................................................41.2关于OFDM的概述............................................................
