Research On Priority Polling Control Strategy Of Wireless Sensor Network

Wireless sensor networks are the new wireless networks, have broadly application foreground. In wireless sensor networks, medium access control(MAC)protocol decides the use mode of wireless channel, assigns limited wireless traffic sources, constructs bottom cadre of wireless sensor networks system, influences obviously the networks performance. Traditional MAC protocol of wireless networks does not meet the requirement of sensor networks for the limited energy, can not be directly applied. So the research on wireless sensor networks MAC protocol becomes popularity, and has very important Practical value.Exact analyses of polling systems form the basis of theory and application. Based on the method of Markov chain theory, the probability generating function and the system state equation methodology this dissertation first sets up the models of Gated and Exhaustive service systems and then gives exact analyses and comparisons of mean queue length, mean cyclic time and throughput and build up the theoretical foundation of research and application in polling system field.Because of its wide application value, polling system based on priority has been studied. Based on the analyses of Exhaustive and Gated service systems this dissertation proposes a new model of two-level-polling system with Exhaustive and Gated service. Using Markov chain theory, the probability generating function and the system state equation methodology the mathematical model of the new system is set up and obtains the accurate expression of the mean queue length, mean cyclic time and throughput, using the theoretical and simulation results to verify the correctness of theoretical analysis.Based on the above two-level-polling system with Exhaustive and Gated service this dissertation studies on the polling scheme for the MAC protocols of Wireless Sensor Network, then provides priority-based polling MAC protocols for the networks. Using Markov chain theory, the probability generating function and the system state equation methodology the mathematical model is set up and mathematical resolving and simulated experiment are conducted on the key parameters of system performance. As a result, it has been testified that the new scheduling strategy works well in providing good service of differentiating priorities according to different demands in WSN. Moreover, it optimizes the performance of network system and reduces the expense on system operation. The findings of this research will be of great help in the enhancement of the system performance.