摘要： 针对SMAC协议退避机制的缺陷，提出一种新的MAC协议——自适应SMAC。在SMAC的基础上引入指数退避机制，引用马尔可夫分析模型对退避关键性能参数进行理论分析，根据分析结果引入信道忙计数器。使节点能根据该计数器估计信道的拥塞程度，自适应地改变竞争窗口大小以减少碰撞，提高能量效率和吞吐率。仿真结果表明，新方案的能量效率和吞吐率相对于SMAC有明显提高。

关键词: 无线传感器网络, MAC协议, 退避机制

Abstract: This paper proposes a new MAC protocol named Self Adaptive SMAC aiming at the deficiencies of back off mechanism in SMAC. Self Adaptive SMAC introduces the exponential back off mechanism based on SMAC, and then analyzes the key performance parameters of the back off process using Markov model. According to the results of the analysis, it further introduces a counter to accumulate the times of busy state of the communication channel, through which nodes have the ability to estimate the congestion situation of the channel. It adaptively changes the size of collision window to reduce collision according to the information about congestion situation, consequently the energy efficiency and throughput are improved. The simulation results later show that Self Adaptive SMAC has better energy efficiency and better channel utilization compared with the original protocol SMAC.

Key words: Wireless Sensor Networks(WSN), MAC protocol, back off mechanism

中图分类号: 

• TP393