基于多速率的无线移动ad hoc网络的研究

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1、思想是根据链路包的丢失率和传输速率来选择从源节点到目的节点期望传输时间最短的路径。首先用模糊Petri网进行建模，接着提出期望介质访问时间路由算法(ExpectMediaVisitingTime，EMVT)。因此，候选路由尽可能多地包含了高传输速率和低包丢失率的链路，可以充分利用物理层多速率能力来提高网络吞吐量。模拟实验表明，期望介质访问时间路由算法比最小跳数路由算法和仅仅考虑链路传输速率路由算法相比，可以较大地提高了网络吞吐量并降低时延。(4)基于网络编码的无线局域网中继算法网络编码是21世纪信息领域的一项新技术

2、，它既可提高网络吞吐量又可节省能量消耗。目前的研究成果主要是基于单速率传输，但随着无线网络技术和设备的不断更新，无线局域网MAC层协议已经开始支持多速率传输。本文将网络编码同无线局域网中多速率传输性质相结合，提出基于网络编码的中继算法(RelayAlgorithmBased0nNetworkCoding，RABNC)，并且分析了其相对传统中继算法的时间减少率。通过模拟实验表明，RABNC算法相对传统的中继算法最高可以节省17％的传输时间。关键词：无线移动AdHoc网，多速率，多播，时延。调度，模糊Petri网，网络

3、编码。ABSTRACTAWirelessAdHOCNetworksiSasetofnodesthatcancommunicatewithothersinamulti—hopfashionwithoutanyassistanceoffixedinfrastructuresandeverynodecanmovefreelyandrelaydataforothers．Itsmainadvantageisthatitcanberapidlydeployedwithoutbasestation．TheWirelessAdHo

4、eNetworksCallbeappliedwherepre·deploymentofnetworkinfrastructureisdifficultorimpossible，forexample，mobilemeeting，disasterareas，andarmiesonthemarch．TheIEEE802．11wirelessmediaaccessstandardinWirelessAdHocNetworkssupportsmultipledataratesatthephysicallayerbyemplo

5、yingdifferentmodulationandchannelcodingschemes．NodescallutilizeautorateadaptationalgorithmbyautomaticallyadaptingthetransmissionratetObestmatchthechannelconditions，andachievesbetternetworkperformance．Researchonmultipletransmissionratesisveryimportantfortheadva

6、ncementofWirelessAdHoeNetworks．Thisthesisstudiesfourmulti-rateissuesforWirelessAdHocNetworks，includingminimizingdelaymuiticastroutinginmulti—rateWirelessAdHoeNetworks，schedulingbasedonmulti-ratetransmissioninWirelessAdHoeNetworks，multi-rateroutinginWirelessAdH

7、oeNetworksbasedonfuzzypetrinet，relayalgorithmbasedonnetworkcodinginwirelesslocalnetwork．Themainresultsofthethesisare辐follows：(1)MinimizingDelayMulticastRoutinginMulti-rateWirelessAdHoeNetworks：Accordingtothemulti-ratecapacityatPHYlayer,theoptimalmulticastdelay

8、inWirelessAdHoeNetworksisstudied．Themainideaisreplacingalowerratetransmissionofupstreamnodewithsometransmissionsfromhightolowtominimizingthemulticastdelayaccordingtocriticalpathbas