ABSTRACT
Abigsteptowardthedevelopmentofatrulyopenandstandardsolutionhasbeendonethanksto theintroductionoftheIEEE802.15.4speci¦cations[I06].Inparticular,thisstandardbodycreateda physicallayer(PHY)descriptionthatmaintainsgoodperformancesinpresenceofnoiseandinterferences,butitissimplyenoughtoallowsystemdesignertoproducelowpowerconsumptionandlowcostdevices.Infact,awirelesssensorforindustrialapplicationsmustworkinanoisyenvironment ononehandandmustensureanoveralldevicelifespanandcostcomparablewithtraditionalwired systems,ontheotherone.¥eadoptionofadirectsequencespreadspectrum(DSSS)strategymitigates interferencesandoªsetquadraturephaseshi¯keyingwithhalf-sineshaping(OQPSK-HSS)modulation ensuresgoodspectraloccupancy.However,theadoptionofcarriersensemultipleaccesswithcollision avoidance(CSMA/CA)atthemediumaccesscontrol(MAC)levelposesseverelimitsontherespectof real-time deadlines, a typical requirement of industrial applications.
