外文翻译原文-基于ZigBee网络的低功耗研究

TheLowPowerStudyBasedonZigBeeNetworkWuLing-xiZhanJieShiWeiHunanUniversityofScienceandTechnologyXiangTan,411201C;JAbstracWInthispaperweanalyzethenodesprocessofbackoffcountdownunderworkingatstartopology,discusstheaccessprobabilityandpowerconsumethatallprobabilitystateofnodesduringasuperframe.ThecourseofpowerconsumeshowedthatitsnotfeasibletoreducesystempowerconsumptionbyadjustingtheTXpower,theonlywayreducingthenodesinthereceivingstateandthesparingtimetocomplete.Alsopointedoutthatthefollowingtwomethodscanreducepowerconsumptionofnodes,usingalongframe,Butlongframewillincreasethedelayandincreasethecostofsystem.Theotheristhrougharelativelyreducednumberofnodestoimproveaccessprobabilitytoachievethegoalofreducingenergyconsumption.KeywordVZigBee;IEEE802.15.4;superframe;MC13192I.INTRODUCTIONZigBeeisawirelesssensornetworkswithshort-range,lowdaterate,energy-efficientdevicesoperatingonbatterypower,basedontheIEEEstandard802.15.4,isintendedtobekeyenabler(enabling)forlowcomplexity,cheap,thatrequirelittleinfrastructuretooperate,ornoneatall.Theagreementobtainedthewidespreadapplication,rapiddevelopment.Itadopthierarchicalstructurebytheapplicationlayer,networklayer,theMAClayerandphysicallayer.Thenetworklayerdealwiththerouteandgatewayofthemeshnetwork.MAClayermangetheaccessandcommunicationofnodes.ThePhysicallayerisresponsibleforsendingandreceivingdata.Thestarnetworkisabasisformofnetwork,itconsistofacoordinateandanumberofnodes,allofthecommunicationofnetworktakeplacebetweenthecoordinateandnodes,thenetworkcarryoutthebeaconframetomanagenodesandsynchronizetime.II.THESTATEANDBACKOFFPROCESSOFNODEBASEDONTHEZIGBEEPROTOCOLAThedescriptionofrunningstateofnodesToexplainthestateofnodethatworkatstartopology,WeintroducetheMC13192astheradiochipofnodes.ItwasproducedbyFreescaleLtd,andconsistentoftheZigBeeprotocol,ittransformstateisshowedasFigure1(here,weconsideronlyuplinktransmission)1.Wecanderivetherelationshipofthestatetransitionandthebackoffcountdownprocessfromthemodelthatnodesaccesschannel2.TXrepresentthenodesuccessaccesschannelandtransmitdata.RXrepresentthreeprocessthatthenodereceivethebeaconframe,theACKsignandexecutetheClearChannelAccessment.Thedifferenceofthreeprocessaretimethatreceivethesign,thebeaconframetimeislongest,ACKisfixed11byteconsumptionbyagreement,CCAoperateonlypersist2byte.Idlerepresentthetimethatnodedidntaccomplishthedatatransmissionontheactivedurationofsuperframe.Hibernatecontainsthreesegment(inactive,activetimeafterthenodeaccomplishdatatransmissionandnodesstateenterthedelayline).FromtheFigure1,Wecanconcludethatthenodeconsumethemaximumenergyatreceiveandsendstate,Hibernateistheeconomystate.Figure1NodeStateconvertBTheBackoffcountdownProcessofNodeAssumethatthereisonlyadatapacketwitheachnodeinthecycleofeachsuperframe,Oncenodesuccesstoaccessthechannel,itcanaccomplishdatatransmission.AccountbyReference345,Wecanintroducefourformulaofprobability.(1)(2)(3)1)1(=n(4)Forclarityofpresentation,.representstheprobabilitythatthechannelisidleafterthefirstCCA,representsthesecondCCA.representstheprobabilitythatnodeaccess=+=mimiiWWx1100,0,0)11)()1(1()1()1(5.05.15.0=+=mimixx010,0,00,0,)1(1)()1(1(1)1(packackpacketnLtL+=978-1-4244-2108-4/08/$25.002008IEEE1Authorizedlicenseduselimitedto:HuaiyinInstituteofTechnology.DownloadedonMarch10,2010at23:24:48ESTfromIEEEXplore.Restrictionsapply.thechannelafterthebackoffcountdownperiodfinished.AccordingtotheProtocol,mrepresentthetimesthatnodeaccessthechannel,0P0:PLQmacMinBE2iW0)5,min(2WmacMinBEiPDF0LQ%(istheminvalueofbackoffexponent.III.THEPROBABILITYANDTIMEOFNODESTATUSATheprobabilityanalysisofnodestateTogetthevalueofpower,Wemustcalculatetheworktimeofeachstatusforsuccesstosenddatapacket,TheyareTTx(sendingpackettime),Tidle(idletimeofthechannel),TRx(receivingstatustime).Here,wedontconsidertheHibernatestatus,becausethestatusconsumeverylowenergy.Forclarity,wedefineBpacketTLLT*)(0+=,L0istheframeheaderoftheMACandPHYlayer.Listhelengthofframe.TBisthetimethatcircuitsendabit.contTistheaveragetimeofcontendchannel,itexpressthenodeconsumetimetosuccesssendingdata.CCANisaveragetimestoexecutetheCCA.=1Prcfexpressthefailureprobabilityofaccessthechannel.FromtheFigure1,wecanderiveusThi18332=(Hibernate-Idletime).usTia194=(Idle-TxorRxtime),)(Pritristheprobabilityofretransmissionith.ustACK192=istheshortesttimeofwaitingtheACKbyProtocoldefined.ustACK864=+isthelongesttimetowaittheACK.So,wecanderivetheprobabilitysequation4)Pr1(*Pr)(Pr1tfitftri=istheithsuccessfulprobability,afterthe(i-1)thtransmissionfail.=mitrtriPmiP1)(1)(expresstheprobabilityithatnodeaccessthechannelisgreatthantheprobabilitym.)Pr1(*)Pr1(1Precoltf=isthetransmissionfailureprobability.ePristhemistakecodeprobability.Weonlyconsideridealchannel,sowecanderivecoltfPrPr=,colPrexpresstheprobabilitythatnodessimultaneouslytransmitdata,thetransmissionwillleadtocollision,So=nnscoltfn)1(1)1(1Pr1PrPr1)1()Pr1(*Pr)(Pr11=itfitftri(5)+=1561)1(*)(655111iiiPiimitr(6)=mitrtriPmiP1)(1)(7)BIdlestatetimecalculateFromFigure1,WecanderiveidleTthatcomposedofthreeparWThi(Hibernate-idleconverttime),Thesecondpartistheconsumedtimethatnodesfailuretoaccesschannelduringthewholeofcontendingchannel,thethirdofparttimeisnoderetransmiti(assumethepacketmustbecompletetransmitting).Wecanexpresstheequation:0)Pr1(*PrTTTTcfcontcfhiidle+=(8)(*)*)(Pr*)(Pr(10+=+=ACKmiconttrtrtTmmiiiTCTxstatetimecalculateWecangettheTxstatetimefromtheI,IIpackettrmitrcfTxTmmiiiT*)(Pr*)(Pr*)Pr1(1+=(9)DTRxstatetimecalculateTRxisconsistedoffourparWstateconverttime,receivingbeaconframetime,thetimethatperformtheCCAandreceiveACKframeatthesuccessaccessingthechannel,performingtheCCAtimeatfailuretoaccesschannel.Here,CCANexpresstheaveragetimesofCCA.32TTTTTbeaconiaRx+=(10)128(*Pr2+=iaCCAcfTNT*)Pr1(3ackACKoocfTtCBT+=)128(*)*)(Pr*)(Pr(1+=iamiCCAtrtroTNmmiiiB=+=miACKotiiC1*)1*)Pr(FromtheReference6,Wecangettheequation:)1()1()(Pr0,0,00,1,0,2,+=+=iiiCCAxxxi22)(1*)(Pr=AiiNiNCCCCA0025.15.01DWA+=)11(*)1(1()1()1(5.0110+=+mimiiWDIV.THEPOWEROFNODESTATECALCULATEANDANALYSISIdlestatepower:BOBidleidleTTIVP2*/*=(11)Txstatepower:BOTxTxTTP2*/*34*7.2B=(12)Rxstatepower:BORxRxTTP2*/*34*7.2B=(13)ThewholeofstatepowerinasuperframeisRxTxidlePPPP+=(14)978-1-4244-2108-4/08/$25.002008IEEE2Authorizedlicenseduselimitedto:HuaiyinInstituteofTechnology.DownloadedonMarch10,2010at23:24:48ESTfromIEEEXplore.Restrictionsapply.Here,TB=aBaesSuperframeDuration,BOistheexponentofbackoffcountdown.WedescribethepowerfromFigure2toFigure5.Figure2describethewholepowerofasuperframe.WecanderiveoftheFigure2thatthenetworkperformanceissimilartothenetworkadoptedtotheCSMA/CA,thepowerrapidlyincreasewiththenumberofnodeandthelengthofthedatapacket.Moreover,theFigureexpressthecharacteroftheZigBee-lowenergy.Figure3isthepoweroftheidlestateitdescribethatthestatespowerandtimearegreaterwiththemorenodesandlongerdataframe,theaccessdelaywillbeincreased,thedataofnodesdontbetransmittonetworkinshorttime.Figure4isthereceivingstatepower.wecangettheideathattheincreaseofnodenumberdontdeeplyaffectthepowerofreceivestatewhenthelengthofframeisshort,moreover,thepowerofreceivingstatewillrapidlyincreasewiththelengthofframe.Comparefigure3tofigure4,wecanderivethatthepowerofreceivingstatewillexceedtheidlestatewiththeincreasingofframelength,thereceivingpowerwillbecomethemainpartofthewholepowerofconsume.Fromthesefigure,wecanconcludethatthelengthofframewilldeeplyaffecttheCCAtimes,atthesametime,augmenttheprobabilityofretransmission,thesefactorsleadthatthenodemustkeepthereceivingstatetowaittheACKframe.Figure5isTxstatepowerinasuperframetime.Itsverylow,anditwilldecreasewiththenumbernodesandthelengthofframeincreasing.ThephenomenonindicatestheaccessprobabilityislowandtheTxstatetimeisshortly.V.CONCLUSIONWediscussthenodepowerofZigBeeprotocolthatworkedunderstartopology,thebeaconenable,wecanconclude:(1)IEEE802.15.4adopttheCSMA/CAagreementwithslots.Themeasureassurethatnodesdontkeepmoretimeatinterceptionstate,andleadtomoreretransmissionandpowerconsume.(2)Wecantdecreasethepowerofnetworkinstartopologybyadjustthetransmitpower.Becausethetransmitpowerholdverylittlepartofallpowerconsume.Wecanonlyreducethepowerthroughdecreasethenumberofnodeandperiodsofreceivingandidlestate.(3)Thelongframecanreducethetransmitstatespower,butitwillrisethewholeofnodepower,moreoverincreasethesystemdelayandcostofhardware.Wehaveaideatoimprovetheaccessprobability,decreasethenodepower.Wecansetuptherelativethataccesstimeandtheframelength,thenodewithlongframeimmediatecompetethechannelafterthebeaconframe,andwiththeshortframedelayaperiodtocompetethechannel.Sothenetworkreducethecompetingnumberofnodesatthesametime,butthemeasurewillincreasethedelayofnetwork,thequestioncannotbeavoidedbecausesharethesinglechannel.Wecandecidehowtousethenetworkbythedifferentapplications.REFERENCES1FreescaleSemiconductor,Inc.802.15.4MAC/PHYS,20042Standardforpart15.4:Wirelessmediumaccesscontrol(MAC)andphysicallayer(PHY)specificationsforlowratewirelesspersonalareanetworks(WPAN),IEEEStd802.15.4,IEEE,NewYork,NY,2003.3J.Misic,S.Shafi,V.B.Misic.Analysisof802.15.4beaconenabledPANinsaturationmode.InProc.Symp.PerformanceEvaluationofComputerandT