Research And Implement Of A WSN Low Power MAC Protocol

Wireless sensor networks will be the 21st century one of the most developed technique.Because of its network fast, flexible, free from the constraints of wired networks and can be widely used for emergency search and disaster relief, environmental monitoring, military applications, such as special environment, it has wide application potential,but the developing of WSN is restructed by power problem,so how to save power always is a big problem which need WSN protocol developer to solve.First of all,This paper reseaches which cause power waste,second, introducestwo sort of the most popular low power MAC protocol--Schedules and LPL,farthercontracts and analyse the advantage and disadvantage of the two sort of protocol.Baseof this work,I designed and implemented a new ultra-low power Mac protocol--EmMAC protocol which syncretize the advantage of Schedules and LPL,and also add some new low power technique.This paper introduces the basic theory of EmMAC protocol,and describes the implementation of the important technique which includes pseud-preamble field technic and channel inspect arithmetic in physical layer,RTS/CTS,NAV,Boot Protocol,synchronization,piggyback,two phase CSMA technic in MAC layer.Finally this paper use testing and debugging interface which are designed by myself to do a integrated test to the whole protocol,the interfaces includes UART debug interface,radio work state time statistic interface,802.15.4 network sniffer and packet analysis tools.This paper designed three different network traffic-loader environment to analyse and contrast the power data between LPL and EmMAC,the test result shows the EmMAC can achieve 97%～99% PSR(Power Save Rate), indeed implement the design aim which is low power consume.And EmMAC shows better adaptability than LPL protocol.