Design-of-Zigbee-Gateway-in-Intelligent-Monitoring

DesignofZigbeeGatewayinIntelligentMonitoringSystemforAgricultureYuanguaiLIN,HaixiaXIE,WeiYANG,XingwuZHENGCollegeofElectronicsInformationandEngineering,QiongzhouUniversitySanYa,Hainan,572022,ChinaEmail:[e-mail]üTheintelligentagriculturalenvironmentmonitoringsystemisoneoftheapplicationsofwirelesssensornetworks(WSNs),whichhasanextensiveapplicationandbrightforeground.Intheintelligentmonitoringsystem,thegatewayisimportantequipmentforrealizingtheinterconnectionbetweenWSNsandinternetfreely.Forthispurpose,thispaperproposesdesignsandimplementsakindofembeddedgatewaybasedonARM9processor.ThecorehardwarechipsareAT91RM9200forARMandJN5139forZigbee,withserialportforthecommunicationeachother,thenextendingmultiplefunctionalhardwaremodules.Atthesametime,onthisplatform,embeddedARMLinuxbasedonversion2.4kernelisintroduced.ExperimentresultsshowthatthegatewayinterconnectstheWSNsandtheinternetfreely,whichdatacanbetransmittedwithEthernet,WLANcommunicationmethods.Ithastheusefulcharacteristicsoflowpowerandreal-time,easytouseandintegration.Keywordsügateway,ARM,embeddedsysytem,Zigbee,wirelesssensornetworksI.INTRODUCTIONInthepracticesofagriculturalinformationization,theagriculturalintelligencemonitoringsystemisanimportantandindispensablelink[1].Theadvancedsensortechnologyandtheintelligenceinformationprocessingtechnologyareimportantmethodtoguaranteecorrectlyandquantitativelytogatheragricultureinformation.Asabrand-newinformationacquisitionandtheprocessingtechnology,thewirelesssensornetworks(WSNs)hasseepedgraduallyintoagriculturaldomainbythecharacteristicssuchaslowpowerloss,lowcostandredundantreliability[2][3].ApplyingZigBeetechnologytodesignanintelligentmonitoringsystemoftheagriculturalenvironmentbasedWSNs.TheproposedintelligentmonitoringsystemforagricultureisillustratedinFigure1[3].Zigbeewascreatedtosatisfythemarket'sneedforacost-effective,standardsbasedwirelessnetworksthatsupportlowdatarates,lowpowerconsumption,security,robustnessandreliability.Toaddressthisneed,theZigbeeAlliance,anindustryworkinggroup,developsstandardizedapplicationsoftwareontopoftheIEEE802.15.4wirelessstandard[5][6].TheallianceworkscloselywiththeIEEEtoensureanintegrated,complete,andinteroperablenetworkforthemarket.Inthissystemthegatewaymanagesthewholenetwork:settingupthewholenetworkfirstly,allocatingtheZigbeeaddresses,addinganddeletingnodes,maintainingthenodeequipmentdataanddatatransfertables,thencommunicateswiththeWSNs.Moreover,itisresponsiblefortheWSNsconnectwithtransmissionnetwork;thecontrolcommandssentbyremotemonitoringcenterawakenallmonitoringnodesviagateway.Thenitcollectsthemonitoringdataanduploadstoremotemonitoringcenter.Forthispurpose,thispaperproposesdesignsandimplementsakindofembeddedgatewaybasedonARM9processor.Wetakedouble-MCUasthecoreplatformofthegateway,basedonembeddedTCP/IPprotocolandZigbee,realizeintegrationofthetwodifferentprotocolstacks[7].II.RELATEDWORKSThemajorapplicationsofWSNsareaimatmonitoringtheambientenvironmentsorinternalconditionsofthetargetsaswellasactuation.Inmostofthecases,WSNscannotoperateincompleteisolation,buttheyneedtobeconnectedwithexternalenvironments.Intheintelligentmonitoringsystemwedesigned,eachnodecanonlycollectparameterssuchastemperature,humidity,etc,butalsoiscapableofdatapackaging,collectedparametermemorizingandroutingtoagateway,thedatafromthemonitoringnodesistransferredtoaremotemonitoringcenterbythegatewayviaatransmissionnetwork.Therefore,howtointerconnectingWSNswiththeInternetisveryimportant.ThereareseveralstudiesandproposalsforinterconnectingWSNswiththeInternet.AnumberofapproachesoninterconnectingWSNswiththeInternethavebeenproposed[8]-[12],mainlyinclude:ķapplication-levelgateway,ĸoverlaynetwork,ĹmodifiedTCP.Theapplication-levelgatewayisrealizedastheimplementationofthefunctionwhichisabletoperformtheprotocoltranslation.ItiscurrentlyadominantapproachforinternetworkingWSNswiththeInternet[8].Thereasonsismulti-fold.Firstly,thisapproachcompletelydecouplesthetwonetworks.ThisnaturallyallowsforspecializedcommunicationprotocolstobeimplementedintheWSNs.Figure1theoverallstructureofmonitoringsystem978-1-61284-722-1/11/$26.00©2011IEEE2011InternationalConferenceonMechatronicScience,ElectricEngineeringandComputerAugust19-22,2011,Jilin,China2213Secondly,thisapproachiseasytoimplement,savethecosttoapply,andsupporttheinternetworkingefficientlyonheterogeneousnetworks.Finally,manystandardsofthisapproachhavebeenacceptedintheindustryforspecificWSNapplications,includingZigBee,ET.Thegatewaywedesignistheapplication-levelgateway.TheoverlaynetworkisusuallybuiltontopoftheInternet,anduseslateaddressbindingtoachievetheindependenceoftheunderlyingbearerprotocolsandaddressingschemes.Asanexample,theInternetandWSNinterconnectioncanbedoneusingadelay-tolerantnetwork(DTN)ontopofthetwonetworks[11].ThemodifiedTCPallowsrunningTCP/IPprotocolsuitedirectlyintheWSNs.Thus,thisapproachprovidestheinterconnectionbetweentheWSNsandtheInternetwithoutrequiringanyproxiesorgateways.III.DESIGNOFZIGBEEGATEWAYInviewoffactorssuchasthecost,integration,controlability,expans