全双工流星余迹通信系统的实现与测试

题（中、英文）目全双工流星余迹通信系统的实现与测试ImplementationandTestforFullDuplexMeteorBurstCommunicationSystem摘要流星余迹通信就是利用流星电离余迹对无线电波的反射和散射作用来进行通信，是一种理想的应急通信手段。本文选题来源于国家“十一五”重点项目，国家自然科学基金(60672129)。流星余迹通信作为一种突发的通信方式，具有抗干扰，不易被截获，单跳通信距离远等特点。然而，流星余迹通信只有在流星出现，在天线照射区内时才能被利用，并且一个流星余迹的持续时间非常短，通常在300~500毫秒，因此提高数据通过率是流星余迹通信要解决的一个主要问题。由于流星信道中存在多径干扰，为了提高通信性能，我们给出了基于OFDM传输的全双工流星余迹通信系统。同时考虑到流星余迹的快衰落特性，采用了自适应变速率方法。为了降低系统的接收门限，提高信道利用率，提出了一种基于OFDM信号功率检测的模拟与数字相结合的自动增益控制方法。最后，通过实验室内和野外线路实验的测试结果表明，这些技术有效地提高了数据通过率。关键词：流星余迹通信OFDM全双工自动增益控制自适应变速摘要AbstractMeteorBurstCommunication(MBC)isaperfectemergencycommunicationmethod,whichusesreflectionanddispersionofradiowavetothemeteorionizationtrails.ThisworkwassupportedinpartbyagrantfromtheKeyProgramsoftheChineseAcademyofSciencesduringthe11thFive-YearPlanPeriod,theNationalNaturalScienceFoundationofChinaunderGrantNo.60672129.Asakindofburstcommunication,MBChassuchcharacteristicsasanti-interference,lowprobabilityofinterception,longrangeforonehop.However,MBCcanbeusedonlywhenmeteorappearsintheirradiationareaofantenna.Thedurationofmeteorbursttrailsisveryshortabout300~500ms,consequently,themainproblemistoimprovethethroughput.Tomitigatethemulti-pathinterferenceinmeteorcommunication,fullduplexMBCsystembasedonOFDMispresented,whichcanimprovetheefficiencyofthetransmission.Inaddition,duetothefastfadingpropertyofmeteorbursttrails,anadaptivevariablerateschemeisproposed.ThenadigitalintegratedwithanalogAGCschemebasedonpowerdetectioninOFDMsignalsisputforwardtoreducethethresholdlevelofsystemandimprovetheutilizationofthechannel.Finally,theefficiencyofthesetechnologiesisdemonstratedbythetestresultsoftransmissionexperimentsinlaboratoryandfield.Keywords:MBCOFDMFullduplexAGCAdaptivevariablerateAbstract目录第一章概述.................................................................................................................11.1引言.................................................................................................................11.2流星余迹的通信机制及特点.........................................................................11.3流星余迹通信的发展历史和现状.................................................................21.4本文所做的工作及内容安排.........................................................................5第二章流星余迹通信的信道及传输特性.................................................................72.1流星的形成和分布.........................................................................................72.1.1流星的形成.............................................................................................72.1.2流星余迹的分类.....................................................................................72.1.3流星余迹的分布...................................................................................102.2流星余迹信道的数学模型...........................................................................122.2.1欠密类余迹的数学模型.......................................................................122.2.2过密类余迹的数学模型.......................................................................142.3流星余迹信道的一些重要参数...................................................................152.4影响传输性能的因素...................................................................................172.5其他传输模式...............................................................................................17第三章流星余迹通信中的关键技术.......................................................................193.1流星OFDM调制解调..................................................................................193.1.1OFDM基本原理..................................................................................193.1.2主要参数选取.......................................................................................203.1.3PAPR的解决........................................................................................213.2自适应变速率传输.......................................................................................243.2.1自适应变速准则...................................................................................253.2.2速率的选取与自适应变速的方法.......................................................263.2.3自适应变速和固定速率的性能比较...................................................263.3流星快衰落信道下的OFDM信号自动增益控制......................................293.3.1自动增益控制技术概述.......................................................................293.3.2复合式AGC控制电路结构................................................................293.3.3OFDM信号的AGC控制方法............................................................30第四章流星余迹通信系统线路测试.......................................................................354.1流星余迹通信系统的组成...........................................................................35目录4.1.1流星余迹通信系统的组成...................................................................354.1.2流星余迹通信系统数字平台...............................................................364.2流星余迹通信系统的主要参数...................................................................384.3线路测试环境...............................................................................................414.4实验结果................................................................