Wireless Sensor Network S-mac Protocol Research

Wireless Sensor Network (WSN) is a late-model wireless network with non-infrastructure and self-organization . With the development of communication technology , micro-electronic and sensor technology , Wireless Sensor Network developed very rapidly and it has attracted a lot of interest from research and industry . Wireless Sensor Network can be widely applied to such situations as: military action , medical treatment, environmental test, disaster rescue , emergency search .Media Access Control (MAC) protocol decides the way what wireless channel used , distributes limited communication resource between sensor nodes , it becomes a focus of studying Wireless Sensor Network . MAC protocol in WSN are mainly classified into two types : contention based MAC protocol ; time division multiple access based MAC protocol . S-MAC protocol is one of the typical contention based MAC protocol .This paper mainly investigates and improves on S-MAC protocol, because it puts forward for WSN's power demand.S-MAC protocol has some problem , such as can not make nodes' active time fit for the dynamic workload and the latency brought about by nodes' sleeping . Combining with T-MAC protocol and D-MAC protocol , we put forward Si-MAC to improve it . In order to solve the border-nodes' energy problem , we adopt global schedule synchronization method to achieve nodes' worktime synchronization . Simulation is operated under NS2 , and the result shows that the improved protocol can ultimately make node fit for the dynamic workload , reducing the latency caused by nodes' sleep , improving border-nodes' energy dissipated problem quickly , and is more advantageous in prolonging Wireless Sensor Network's lifetime.