| As the result of fast deployment, robustness and independence of wireless sensor networks (WSNs), WSNs has recently received a lot of attention on the international research field. And WSNs' nature makes it more attractive for military applications and other wide range of applications, such as environmental monitoring, earthquake and climate forecasting , space exploring. Nevertheless, it is a revolution of information sensing and collection method and one of the important technologies in 21 century.Medium access control (MAC) protocol for WSNs provides the technique that decides how to share the cannel among WSN nodes, and it is the basic structure of WSNs. The tiny sensor nodes have limited low cost, power, computational capacity, bandwidth and memory. And WSNs must possess self-organizing capabilities and centreless architecture to ensure a wide range of applications. Conventional MAC mechanism can hardly provide good performance in such complex environment of distributed networks. Consequently it is meaningful to develop MAC techniques with adaptive abilities in wireless sensor networks.This paper is dedicated to the research of WSN's MAC protocol. Firstly, by the basic concept, architecture, feature and performance standard of WSN, we analyzed the popular WSN MAC protocols based on competition. then, for the feature of WSN, we provided a new asynchronous adaptive MAC protocol based on competition: AAMAC. This MAC protocol shorted the preamble length of asynchronous MAC in WSN, and used adaptive listening. This MAC protocol makes the number of sending packet of fewer and the node's working time shorted. WSN node Simulating on NS2, we found the AAMAC has better energy and latency efficiency than other similar MAC protocols. |
