基于IEEE80211a的OFDM基带接收系统设计与FPGA实现

硕士学位论文论文题目：基于IEEE802.11a的OFDM基带接收系统设计与FPGA实现英文题目：DesignofOFDMBasebandReceivingSystemBasedonIEEE802.11aandRealizationonFPGA学位类别：工程硕士研究生姓名：刘乃君学号：201102302学科(领域)名称：计算机技术指导教师：崔丽珍职称：教授协助指导教师：职称：2013年6月6日分类号：TN92密级：公开UDC：学校代码：10127内蒙古科技大学硕士学位论文I摘要随着无线通信技术的飞速发展，移动通信系统经历了从1G向4G的发展。在未来的无线通信中，蜂窝数据计划将逐渐被无线热点所取代，更多的无线通信新技术将会涌现出来，这些技术大都采用OFDM技术。由此可见，OFDM代表了未来通信技术的发展方向，是未来通信的基础。IEEE802.11a标准组也选用了OFDM技术作为工作于5GHz频段的无线局域网（WLAN）的物理层接入方案。该频段的可用频率资源非常丰富，可以缓解WLAN面临的频率干扰问题，在抗干扰性上较IEEE802.11b更为出色。OFDM技术是多载波技术和频分复用技术有效结合的产物，以其频谱利用率高、抗多径衰落、频谱资源分配灵活、易与多种技术相结合等优点成为当今通信领域备受瞩目的技术之一。OFDM系统的发射数据经过干扰后最终恢复出原始数据的正确性与接收机的设计密切相关，FPGA为OFDM基带接收系统的设计提供了重要手段。本课题以VerilogHDL为编程语言，ISE13.4为软件开发环境，XilinxVirtex-5FPGA为硬件平台进行OFDM基带接收系统的设计与实现。发射端发射的数据经过信道后会加入噪声，所以接收端接收的数据首先要进行同步，提取出数据分组信息，通过频偏估计和补偿，保证FFT的正确进行。由于在发射端加入了循环前缀来最大限度的消除ISI和ICI，所以在将数据送入FFT处理之前，首先要去除循环前缀，保证64点FFT的正确进行。经过信道中噪声的干扰后，数据的幅值和相位都会发生偏差，信道估计与均衡模块利用两个长训练序列中的信息，纠正幅值和相位。信号域处理部分经过去导频、解映射、解交织、Viterbi译码后得到数据域解调所用到的相关信息。数据域处理部分经过去导频、解映射、解交织、Viterbi译码、解扰码后恢复出原始数据。通过对单个模块进行设计和仿真后，对整个接收机进行联调，最终利用FPGA硬件平台实现，从而验证接收机的可行性。本课题对OFDM系统的硬件实现具有重要参考意义。关键词：OFDM；FPGA；IEEE802.11a；接收系统内蒙古科技大学硕士学位论文IIAbstractWiththerapiddevelopmentofwirelesscommunicationtechnology,mobilecommunicationsystemhasdevelopedfrom1Gto4G.Wirelesshotspotwillgraduallyreplaceofcellulardataplansinthefutureandmorewirelesscommunicationtechnologieswillbeproduced.Inaddition,mostofthesetechniquestakeadvantageofOFDMtechnology.Therefore,OFDMisthebasisofcommunicationsandrepresentsthedevelopmentdirectionofcommunicationtechnologyinthefuture.ThecriteriongroupofIEEE802.11aalsoselectedOFDMasthephysicalaccessschemeofwirelessLAN(WLAN)in5GHzfrequencybands.Theavailablefrequencyresourcesinthebandareveryrich,andcomparingwithIEEE802.11b,ithasbetterperformanceinanti-interferenceaswellascanalleviatefrequencyinterferenceproblemsoftheWLAN.OFDMisapotentcombinationofmulti-carriertechnologyandfrequencydivisionmultiplexingtechnology,andithasalreadybecomeoneofthemostsignificanttechnologiesinthefieldofcommunicationwithitshighspectrumefficiency,resistancetomultipathfading,flexibleallocationofspectrumresources,andeasytobecombinedwithavarietyoftechnical.ThereisadefinitelinkbetweenthecorrectnessofeventuallyrecovertheoriginaldatawhentheOFDMsystem’stransmitdataafterinterferenceandreceiverdesign,FPGAprovideanimportanttoolforthedesignofOFDMbasebandreceivingsystem.ThepaperaimstoachievethedesignandimplementationofOFDMbasebandreceivingsystemwithVerilogHDLprogramminglanguage,ISE13.4softwaredevelopmentenvironmentandXilinxVirtex-5FPGAhardwareplatform.Thedatafromthetransmitterwillbeaddednoiseaftergoingintothechannel,sofirstthedatafromreceivershouldbesynchronizedandbeextractedthedatapacketinformationtomakesurethecorrectnessofFFTbythefrequencyoffsetestimationandcompensation.In内蒙古科技大学硕士学位论文IIIordertomaximizetheeliminationofISIandICI,cyclicprefixisaddedtothetransmitter,sobeforethedataisprocessedbyFFT,thecyclicprefixshouldberemovedtoensurethecorrectnessofthe64FFT.Aftertheinterferenceofthenoisewhichisfromthechannel,theamplitudeandphasedatawillbiasandchannelestimationandequalizationmoduleusetheinformationfromthetwolongtrainingsequencestocorrecttheamplitudeandphase.Thesignalprocessingpartobtainstherelatedinformationwhichisusedinthedataprocessingpartbydismissingpilot,demapping,deinterleaving,Viterbidecoding.Thedataprocessingpartrecoverstheoriginaldatabydismissingpilot,demapping,deinterleaving,Viterbidecoding,descrambling.Thedesignandsimulationofsinglemodule,thedebuggingofthereceiverandtheFPGAhardwareplatformverifiedthefeasibilityofthereceiver.ThepaperhasansignificantinfluenceonthehardwareoftheOFDMsystem.KeyWords：OFDM；FPGA；IEEE802.11a；Receiver内蒙古科技大学硕士学位论文-1-目录摘要...........................................................................................................................................IAbstract............................................................................................................................................II引言......................................................................................................................................-1-1绪论..........................................................................................................................................-2-1.1移动通信概述..............................................................................................................-2-1.2OFDM技术及其发展..................................................................................................-3-1.3课题研究背景及意义..................................................................................................-4-1.4本文主要研究内容......................................................................................................-5-2OFDM技术和IEEE802.11a标准........................................................................................-7-2.1OFDM技术...................................................................................................................-7-2.1.1OFDM原理.........................................................................