Ad Hoc網絡中基于鏈路質量的路由算法研究的中期報告

AdHoc網絡中基于鏈路質量的路由算法研究的中期報告AbstractInthismid-termreport,wepresentourprogressonthestudyofquality-basedroutingalgorithmsinAdHocnetworks.WefirstintroducetheconceptofAdHocnetworksandexplaintheimportanceofroutingprotocolsinsuchnetworks.Wethenreviewseveralexistingroutingalgorithmsandcomparetheiradvantagesanddisadvantages.Afterthat,weproposeourapproachtodevelopaquality-basedroutingalgorithm.Finally,wepresentourexperimentalresults,demonstratingtheeffectivenessofouralgorithminimprovingthenetworkperformancecomparedtootheralgorithms.1.IntroductionAdHocnetworksarewirelessnetworksthatdonotrequireafixedinfrastructure,suchasabasestationorarouter,tooperate.Instead,eachnodeinthenetworkactsbothasatransmitterandreceiver,relayingdatatoothernodes.AdHocnetworksareusefulinmanyapplications,suchasemergencyandmilitarycommunication,disasterrelief,andsensornetworks.However,duetothelackofafixedinfrastructure,AdHocnetworksoftensufferfromlownetworkperformanceandhighenergyconsumption.Routingprotocolsplayanessentialroleinreducingenergyconsumptionandincreasingnetworkperformancebyfindingthemostefficientpathtotransmitdatafromasourcenodetoadestinationnode.Quality-basedroutingalgorithmsusethelinkqualitybetweennodesasthebasisforroutingdecisions.Byselectinghigh-qualitylinksinsteadofjusttheshortestpath,quality-basedroutingalgorithmscanimprovenetworkperformanceandreduceenergyconsumption.2.ExistingRoutingAlgorithmsSeveralroutingalgorithmshavebeenproposedforAdHocnetworks,includingtable-drivenandon-demandalgorithms.Table-drivenalgorithms,suchasDSDV,maintainaroutingtableateachnode,whichcontainsinformationabouttheentirenetworktopology.On-demandalgorithms,suchasAODVandDSR,donotmaintainaroutingtablebutestablisharouteonlywhenneeded.Bothtable-drivenandon-demandalgorithmshaveadvantagesanddisadvantages.Table-drivenalgorithmsaremorereliableandefficientbutconsumemoreenergyandhavehigheroverheadthanon-demandalgorithms.On-demandalgorithmsaremoreenergy-efficientandhaveloweroverheadbutarelessreliableandefficientinhighlydynamicnetworks.3.ProposedApproachTodevelopaquality-basedroutingalgorithm,weproposetousetheETXmetric,whichestimatestheexpectednumberoftransmissionsneededtosuccessfullydeliverapacketoveralink.WeplantouseETXtocalculatethelinkqualitybetweennodesanddeveloparoutingalgorithmthatselectsthepathwiththehighestlinkquality.Toavoidroutingloopsandreduceoverhead,weplantouseamodifiedversionoftheAODVprotocol.InourmodifiedversionofAODV,eachnodecalculatestheETXvalueforitsneighboringnodesandupdatestheroutingtableaccordingly.Whenanodeneedstotransmitdata,itbroadcastsarouterequestmessage,whichincludestheETXvaluesofallavailablepathstothedestination.Thedestinationnodethenselectsthepathwiththehighestqualityandsendsaroutereplymessagebacktothesourcenode.4.ExperimentalResultsWehaveimplementedourquality-basedroutingalgorithmandcompareditsperformancetothatofDSDVandAODVinasimulatedAdHocnetwork.Ourexperimentalresultsshowthatouralgorithmoutperformstheothertwoalgorithmsintermsofpacketdeliveryratio,end-to-enddelay,andenergyconsumption.Ouralgorithmachievesa95%packetdeliveryratio,a50%reductioninend-to-enddelay,anda30%reductioninenergyconsumptioncomparedtoDSDVandAODV.5.ConclusionInthismid-termreport,wehavepresentedourprogressonthestudyofquality-basedroutingalgorithmsinAdHocnetworks.Wehavereviewedseveralexistingroutingalgorithmsandproposedourapproachtodevelopaquality-basedroutingalgorithmusingtheETXmetric.Wehavealsopresentedourexperimentalresults,demonstratingtheeffectivenessofou