A Traffic-Aware MAC Protocol Based on Dynamic Contention Windows in Wireless Sensor Networks

Wireless sensor networks are formed by a great deal of sensor nodes, which are generally battery-powered and may not be recharged easily. Consequently, how to save energy is an important issue when designing protocol in wireless sensor network. However, lowering the energy consumption may result in higher latency. To address such a tradeoff, this paper proposes a MAC protocol supported dynamic contention window size. Compared with S-MAC using fixed contention window sizes, TrawMAC adaptively adjusts the contention window size, based on some relevant network statistics. Those statistics guides the strategy of adjusting the CW size. The experiment results show that TrawMAC saves energy about 85.19% and reduce latency by 66.86% from S-MAC in a chain topology. In the cross topology, it also achieves 81.11%energy saving and 37.2%latency reduction from S-MAC.