Mac Layer Protocol In Wireless Sensor Networks Research And Improvement

Wireless sensor networks combines sensor technology, embedded computing technology, distributed information processing technology and wireless communication technology.It layouts a lot of inexpensive sensor nodes to the area where to be monitored and passes the information to the sink nodes through multi-hop. The energy of the node is limited because the working environment is limited and the power can't be replaced, so the most important problem is how to use the energy more efficiently to extend the network's life.In WSN, medium access control(MAC)protocols determine the usage mode of wireless channel,allocate limited radio resource among sensor nodes and construct infrastructure.MAC protocols have a great influence on the WSN performance. MAC protocols of traditional wireless networks can't meet the design requirements for WSN,So they can't be used directly.Research on MAC protocols of WSN always attract a lot of attention.This paper analyzes the structure,protocol stack,application and development.The main work of the paper is as follows:1) Through the analysis of the characteristics of WSN,the paper discussed the impact of MAC protocol problems related to the design,and mainly discussed the S-MAC protocols and compare their performance and characters.2) The paper used NS2 simulation platform to compare the energy consumption, throughput of S-MAC protocol.The simulation results show that the CW has a important impact on the ability of node's ability of competing channel. Then proposed a dynamic design of CW which based on the energy consumption. So that the node having few energy don't need to attend the data sending.3) The paper added the routing information to the node wake-up mechanism, and used matlab to simulation a 100 nodes scenario. In this scenario we used the genetic algorithm to find an optimal path based on energy consumption.4) Through these simulation and analysis, we can concluded the improved protocol is better than the original S-MAC protocol.At the end of the paper, there are a conclusion of done work and a plan of future work..