ASimpleEnergyModelforWirelessMicrosensorTransceiversAbstract—Thispaperdescribesthemodellingofshortrangetransceiversformicrosensorapplications.Asimpleenergymodelisderivedandusedtoanalyzethetransceiverbatterylife.Thismodeltakesintoaccountenergydissipationduringthestart-up,receive,andtransmitmodes.Itshowsthatthereisasignificantfixedcostinthetransceiverenergyconsumptionandthisfixedcostcanbedrivendownbyincreasingthedatarateofthetransceiver.I.IntroductionWirelessmicrosensornetworkscanprovideshort-rangeconnectivitywithsignificantfaulttolerances.Thesesystemsfindusageindiverseareassuchasenvironmentalmonitoring,industrialprocessautomation,andfieldsurveillance.Asanexample,TableIshowsadetailedspecificationforasensorsystemusedinafactorymachinemonitoringenvironment.Themajorcharacteristicsofamicrosensorsystemarehighsensordensity,shortrangetransmissions,andlowdatarate.Dependingontheapplication,therecanalsobestringentBERandlatencyrequirements.Duetothelargedensityandtherandomdistributednatureofthesenetworks,batteryreplacementisadifficulttask.Infact,aprimaryissuethatpreventsthesenetworkstobeusedinmanyapplicationareasistheshortbatterylife.Therefore,maximizingthebatterylifetimeofthesensornodesisimportant.Figure1showsthepeakcurrentconsumptionlimitwhena950mAhbatteryisusedastheenergysource.Asseeninthefigure,batterylifecanvarybyordersofmagnitudedependingonthedutycycleofeachoperation.Toallowforhighermaximumpeakcurrent,itisdesirabletohavethesensorremainintheoff-stateforaslongaspossible.However,thelatencyrequirementofthesystemdictateshowoftenthesensorneedstobeactive.Fortheindustrialsensorapplicationdescribedabove,thesensorneedstooperateevery5mstosatisfythelatencyrequirement.Assumingthatthesensoroperatesfor100µsevery5ms,thedutycycleis2%.Toachieveaone-yearbatterylife,thepeakcurrentconsumptionmustbekeptunder5.4mA,whichtranslatestoapproximately10mWat2Vsupply.Thisisadifficulttargettoachieveforsensorsthatcommunicateatgiga-Hertzcarrierfrequencies.Therehasbeenactiveresearchinmicrosensornetwork