通信工程-专业英语论文

《专业英语》课程论文论文题目：WirelesssensornetworknodePositioningalgorithm学院(系)：信息工程学院专业：电子科学与技术班级：信研135班学生姓名：胡剑学号：1049721303194教师：徐文君2014年5月16日WirelesssensornetworknodepositioningalgorithmHujianSchoolofInformationEngineering,WuhanUniversityofTechnology,Wuhan,[e-mail]-Wirelesssensornetworksasanewtypeofdataacquisitiontechnology,combinedwithmicroelectronics,wirelesscommunicationsandwirelessnetworks,suchasmulti-discipline,havebroadapplicationprospectsinthefieldofindustrialcontrol,military,medicalassistance,andenvironmentalmonitoring.Inmostapplications,thephysicallocationoftheguidetothesensornodeisabasicrequirement,however,duetothelargenumberofsensornodes,randomlydistributed,andthesoftwareandhardwareresourcesarelimited,sostudyeffectivepositioningalgorithmtodeterminethelocationofeachnodehasanimportanttheoreticalsignificanceandpracticalvalue.Accesstolargeamountsofliteratureonthebasisofthelessonsdoanoverviewofthewirelesssensornetwork-basedpositioningtechnology,wirelesssensornetworks,highlightsseveraltypicaldistributedpositioningalgorithmprincipleandcharacteristics,includingAmorphous,APIT,Centroid,DV-Hop,RSSI,etc.,itsMatlabsimulationenvironmentsimulationanalysis,andcomparethepositioningaccuracyofthevariousalgorithmsanderror.Keywords:wirelesssensornetworks,localizationalgorithm,Matlab,simulationanalysisI.INTRODUCTIONPositioningofwirelesssensornetworksisthewireless,self-organizingnetworktoprovidelocationinformationofnodesinthenetworkinsomeway,self-organizingnetworklocalizationprocesscanbedividedintoself-positioningandtargetingnodenodepositioningitselftodeterminethecoordinatesoftheinformationnetworknode.Thetargetinginformationisneededtodeterminethecoordinatesofatargetwithinthenetworkcoverageoranevent.Nodeitselfistheprocessofdeterminingthepositioningpropertiesofthenetworkitself,oryoucanusethemanualcalibrationofvariousnodelocalizationalgorithmtocomplete.Targetingthelocationofthenetworknodesisknownasthereferencenode,thedestinationnodedeterminesthattheeventorthelocationinthenetwork.II.SYSTEMDESIGNTInsensornetworks,mostexistingnodelocalizationalgorithms,referenceanchornodesarepositionedtotakeadvantageofthewayplace.Alargenumberofsensornodesinthetargetareainthelayout:aportioncalledtheparticularnode,alsocalledanchornode(beacon),whichthemselvescanbeobtainedbycarryingtheexactlocationoftheGPSpositioningapparatusorartificialmeans,andhavemorethannodepowerfulcapabilities,butsuchasmallproportionofnodes;nodeotherunknownlocationsthemselves,throughtheirneighbornodestocommunicatetogetinformationofeachanchornodes,thesenodesusingthelocationinformationasareference,andusesomecalculationstogettheirpositionknowntotheunknowniscalledanode(node)Inwirelesssensornetworksusuallyusedonlytwo-dimensionalcoordinatesystemof.Solongasweknowfromtheunknownnodewiththreeanchornodescancalculatethepositionoftheunknownnode.Figure1.SchematictrilateralpositioningAssumingthreeanchornodecoordinatesare(X1,Y1),(X2,Y2),(X3,Y3),thecoordinatesoftheunknownnode(Xu,Yu),unknownnodedistancesfromthreeanchornodesareR1,R2,R3,showninFigure3-2,thedistanceformulabasedonatwo-dimensionalcoordinatesystemofequationscanbeobtainedasfollows:(1)Theaboveequationsareusuallysolvedusingthemaximumlikelihoodmethodestimatestheunknownnodecoordinatemultilateralused(Xu,Yu)：(2)Insummary,itmayobtainapluralityofunknownnodesaslongastheanchornodethattheunknowndistancefromthenodetotheanchornode3maybepositionedonthepracticalapplicationoftheunknownnode,thiscalculationcanbedifferentforeachselectedthreepoints,andfinallyTheresultswereaveragedforseveraltimesandthusimprovethepositioningaccuracy.III.SpecificpositioningalgorithmA.APITAlgorithmAPITalgorithmtheoreticalbasisisthebestpointinsidethetriangletestmethodPIT.PITtestprincipleisthatifthereisadirectionunknownnodessimultaneouslymovingalongthisdirectionawayfromorclosetothreebeaconnodes,thentheunknownnodeslocatedinthreebeaconnodesoutsidethetriangle;otherwiseunknownnodeslocatedwithinthetriangle.Pointtestusingthenetworkinarelativelyhighdensityofnodestosimulatethemobilenodesusingwirelesssignalpropagationcharacteristicstodeterminewhetherfarornearbeaconnodeswithintheapproximatetriangle,usuallyinagivendirection,anodefromanothernodethefartherthereceivedsignalstrengthisweaker.Neighbornodesexchangetheirreceivedsignalstrengthdeterminationofadistanceofbeaconnodes,thenodestomovemimicPIT.B.CentroidPositioningAlgorithmCentroidalgorithm,thebeaconnodetoaneighboringnodeperiodicallybroadcastsabeaconpacket,abeaconpacketcontainstheidentificationnumberandthelocationinformationofbeaconnodes.Whenthenodereceivestheunknownnumberofdifferentbeaconbeaconpacketfromanodeorreceptionexceedsacertainthresholdtime,thepositionofwhichdeterminesitsbeaconnodesconsistingofthecentroidofthepolygon.Centroidalgorithmbasedsolelyonnetworkconnectivity,andthereforerelativelyeasytoimplement.However,thismethodisaffectedbythedensityofthebeaconnodes.Centroidalgorithmforimprovedalgorithm,densityadaptiveHEAPalgorithm,byincreasingthebeaconbeaconnodesnodesinalowdensityareainordertoimprovethepositioningaccuracy.