zigbee无线传感器网络英文文献.docx
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zigbee无线传感器网络英文文献.docx
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zigbee无线传感器网络英文文献
zigbee无线传感器网络英文文献
兰州交通大学毕业设计(英文文献)
ZigbeeWirelessSensorNetworkinEnvironmentalMonitoring
Applications
I.ZIGBEETECHNOLOGY
ZigbeeisawirelessstandardbasedonIEEE802.15.4thatwasdevelopedtoaddressthe
uniqueneedsofmostwirelesssensingandcontrolapplications.Technologyislowcost,lowpower,alowdatarate,highlyreliable,highlysecurewirelessnetworkingprotocoltargetedtowardsautomationandremotecontrolapplications.It’sdepictstwokey
performancecharacteristics–wirelessradiorangeanddatatransmissionrateofthewirelessspectrum.ComparingtootherwirelessnetworkingprotocolssuchasBluetooth,Wi-Fi,UWBandsoon,showsexcellenttransmissionabilityinlowertransmissionrateandhighlycapacityofnetwork.
A.ZigbeeFramework
Frameworkismadeupofasetofblockscalledlayers.Eachlayerperformsaspecific
setofservicesforthelayerabove.AsshowninFig.1.TheIEEE802.15.4standarddefines
thetwolowerlayers:
thephysical(PHY)layerandthemediumaccesscontrol(MAC)layer.TheAlliancebuildsonthisfoundationbyprovidingthenetworkandsecuritylayerandtheframeworkfortheapplicationlayer.
Fig.1Framework
TheIEEE802.15.4hastwoPHYlayersthatoperateintwoseparatefrequencyranges:
868/915MHzand2.4GHz.Moreover,MACsub-layercontrolsaccesstotheradiochannelusingaCSMA-CAmechanism.Itsresponsibilitiesmayalsoincludetransmittingbeaconframes,synchronization,andprovidingareliabletransmissionmechanism.B.Zigbee’sTopology
Thenetworklayersupportsstar,tree,andmeshtopologies,asshowninFig.2.Inastar
topology,thenetworkiscontrolledbyonesingledevicecalledcoordinator.Thecoordinator
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兰州交通大学毕业设计(英文文献)
isresponsibleforinitiatingandmaintainingthedevicesonthenetwork.Allotherdevices,knownasenddevices,directlycommunicatewiththecoordinator.Inmeshandtreetopologies,thecoordinatorisresponsibleforstartingthenetworkandforchoosingcertainkeynetworkparameters,butthenetworkmaybeextendedthroughtheuseofrouters.Intreenetworks,routersmovedataandcontrolmessagesthroughthenetworkusingahierarchicalroutingstrategy.Meshnetworksallowfullpeer-to-peercommunication.
Fig.2Meshtopologies
Fig.3isanetworkmodel,itshowsthatsupportsbothsingle-hopstartopologyconstructedwithonecoordinatorinthecenterandtheenddevices,andmeshtopology.Inthenetwork,theintelligentnodesarecomposedbyFullFunctionDevice(FFD)andReducedFunctionDevice(RFD).OnlytheFFNdefinesthefullfunctionalityandcanbecomeanetworkcoordinator.Coordinatormanagesthenetwork,itistosaythatcoordinatorcanstartanetworkandallowotherdevicestojoinorleaveit.Moreover,itcanprovidebindingandaddress-tableservices,andsavemessagesuntiltheycanbedelivered.
Fig.3Zigbeenetworkmodel
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兰州交通大学毕业设计(英文文献)
II.THEGREENHOUSEENVIRONMENTALMONITORING
SYSTEMDESIGN
Traditionalagricultureonlyusemachineryandequipmentwhichisolatingandnocommunicatingability.Andfarmershavetomonitorcrops’growthbythemselves.Evenif
somepeopleuseelectricaldevices,butmostofthemwererestrictedtosimplecommunicationbetweencontrolcomputerandenddeviceslikesensorsinsteadofwireconnection,whichcouldn’tbestrictlydefinedaswirelesssensornetwork.Therefore,by
throughusingsensornetworksand,agriculturecouldbecomemoreautomation,morenetworkingandsmarter.
Inthisproject,weshoulddeployfivekindsofsensorsinthegreenhousebasement.Bythroughthesedeployedsensors,theparameterssuchastemperatureinthegreenhouse,soiltemperature,dewpoint,humidityandlightintensitycanbedetectedrealtime.Itiskeytocollectdifferentparametersfromallkindsofsensors.Andinthegreenhouse,monitoringthevegetablesgrowingconditionsisthetopissue.Therefore,longerbatterylifeandlowerdatarateandlesscomplexityareveryimportant.Fromtheintroductionaboutabove,weknowthatmeettherequirementsforreliability,security,lowcostsandlowpower.
A.SystemOverview
TheoverviewofGreenhouseenvironmentalmonitoringsystem,whichismadeupbyonesinknode(coordinator),manysensornodes,workstationanddatabase.Motenodeandsensornodetogethercomposedofeachcollectingnode.Whensensorscollectparametersrealtime,suchastemperatureinthegreenhouse,soiltemperature,dewpoint,humidityandlightintensity,thesedatawillbeofferedtoA/Dconverter,thenbythroughquantizingandencodingbecomethedigitalsignalthatisabletotransmitbywirelesssensorcommunicatingnode.Eachwirelesssensorcommunicatingnodehasabilityoftransmitting,receivingfunction.
InthisWSN,sensornodesdeployedinthegreenhouse,whichcancollectrealtimedataandtransmitdatatosinknode(Coordinator)bythewayofmulti-hop.Sinknodecompletethetaskofdataanalysisanddatastorage.Meanwhile,sinknodeisconnectedwithGPRS/CDMAcanprovideremotecontrolanddatadownloadservice.Inthemonitoringandcontrollingroom,byrunninggreenhousemanagementsoftware,thesinknodecanperiodicallyreceivesthedatafromthewirelesssensornodesanddisplaysthemonmonitors.
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兰州交通大学毕业设计(英文文献)
B.NodeHardwareDesign
SensornodesarethebasicunitsofWSN.Thehardwareplatformismadeupsensornodescloselyrelatedtothespecificapplicationrequirements.Therefore,themostimportantworkisthenodesdesignwhichcanperfectimplementthefunctionofdetectingandtransmissionasaWSNnode,andperformitstechnologycharacteristics.Fig.4showstheuniversalstructureoftheWSNnodes.Powermoduleprovidesthenecessaryenergyforthesensornodes.Datacollectionmoduleisusedtoreceiveandconvertsignalsofsensors.Dataprocessingandcontrolmodule’sfunctionsarenodedevicecontrol,taskscheduling,and
energycomputingandsoon.Communicationmoduleisusedtosenddatabetweennodesandfrequencychosenandsoon.
Fig.4Universalstructureofthewsnnodes
Inthedatatransferunit,themoduleisembeddedtomatchtheMAClayerandtheNETlayeroftheprotocol.WechooseCC2430astheprotocolchips,whichintegratedtheCPU,
RFtransceiver,netprotocolandtheRAMtogether.CC2430usesan8bitMCU(8051),and
has128KBprogrammableflashmemoryand8KBRAM.ItalsoincludesA/Dconverter,someTimers,AES128Coprocessor,WatchdogTimer,32KcrystalSleepmodeTimer,Power
onReset,BrownoutDetectionand21I/Os.Basedonthechips,manymodulesforthe
protocolareprovided.Andthetransferunitcouldbeeasilydesignedbasedonthemodules.
Asanexampleofasensorenddeviceintegratedtemperature,humidityandlight,thedesignisshowninFig.5.
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兰州交通大学毕业设计(英文文献)
Fig.5Thehardwaredesignofasensornode
TheSHT11isasinglechiprelativehumidityandtemperaturemultisensormodulecomprisingacalibrateddigitaloutput.Itcantestthesoiltemperatureandhumidity.TheDS18B20isadigitaltemperaturesensor,whichhas3pinsanddatapincanlinkMSP430
directly.Itcandetecttemperatureingreenhouse.TheTCS320isadigitallightsensor.
SHT11,DS18B20andTCS320arebothdigitalsensorswithsmallsizeandlowpower
consumption.Othersensornodescanbeobtainedbychangingthesensors.
Thesensornodesarepoweredfromonboardbatteriesandthecoordinatoralsoallowstobepoweredfromanexternalpowersupplydeterminedbyajumper.
C.NodeSoftwareDesign
Theapplicationsystemconsistsofacoordinatorandseveralenddevices.Thegeneralstructureofthecodeineachisthesame,withaninitializationfollowedbyamainloop.
Thesoftwareflowofcoordinator,uponthecoordinatorbeingstarted,thefirstactionoftheapplicationistheinitializationofthehardware,liquidcrystal,stackandapplicationvariablesandopeningtheinterrupt.Thenanetworkwillbeformatted.Ifthisnethasbeenformattedsuccessfully,somenetworkinformation,suchasphysicaladdress,netID,channelnumberwillbeshownontheLCD.Thenprogramwillstepintoapplicationlayerandmonitorsignal.Ifthereisenddeviceorrouterwanttojoininthisnet,LCDwillshownthisinformation,andshowthephysicaladdressofapplyingnode,andthecoordinatorwillallocateanetaddresstothisnode.Ifthenodehasbeenjoinedinthisnetwork,thedatatransmittedbythisnodewillbereceivedbycoordinatorandshownintheLCD.
Thesoftwareflowofasensornode,aseachsensornodeisswitchedon,itscansall
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兰州交通大学毕业设计(英文文献)
channelsand,afterseeinganybeacons,checksthatthecoordinatoristheonethatitislookingfor.Itthenperformsasynchronizationandassociation.Onceassociationiscomplete,thesensornodeentersaregularloopofreadingitssensorsandputtingoutaframecontainingthesensordata.Ifsendingsuccessfully,enddevicewillstepintoidlestate;bycontrast,itwillcollectdataonceagainandsendtocoordinatoruntilsendingsuccessfully.
D.GreenhouseMonitoringSoftwareDesign
WeuseVBlanguagetobuildaninterfaceforthetestandthisgreenhousesensornetworksoftwarecanbeinstalledandlaunchedonanyWindows-basedoperatingsystem.Ithas4
dialogboxselections:
settingcontrollingconditions,settingTimer,settingrelevantparametersandshowingcurrentstatus.Bysettingsomeparameters,itcanperformthefunctionsofcommunicatingwithport,datacollectionanddataviewing.
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兰州交通大学毕业设计(英文文献)
无线传感器网络在环境监测中的应用Zigbee
技术I.Zigbee
是一种基于802.15.4的无线标准上被开发用来满足大多数无线传感ZigbeeIEEE
和控制应用的独特需求。
技术是低成本,低功耗,低数据速率,高可靠性,高Zigbee
度安全的无线网络协议实现自动化和远程控制应用的目标。
它描述了两个关键的性能特点—无线射频范围和无线频谱的数据传输速率。
相较于其他如蓝牙,技术,超Wi-Fi宽带等无线网络协议,虽然传输速率慢但传输容量大的特点向我们展示了他出Zigb
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