通过分析IEEE802.11DCF的性能及存在问题,在此基础上提出一种改进的基于滑动概率pw的分布式协调功能asyn—DCF。该机制采用一种异步退避算法,通过加入滑动概率pw使得退避计数器在信道空闲的情况下以一定的概率pw来退避,从而达到减少冲突的目的。该算法采用二维Markov chain模型对改进机制的性能进行理论分析,结果表明了该算法能够有效地提高饱和吞吐量并且减少包碰撞概率。
After analyzing the performance of IEEE 802.11 DCF and it' s problem, a novel asynchronous backoff algorithm of 802.11 DCF, i.e. asyn-DCF, is proposed. In this new algorithm, backofftimers of all the stations in the WLAN are decreased with a sliding probability ofp~ if the state of channel is idle. Then, a Markov chain model is used in this work, to analyze and evaluate the performance of the new mechanism in the basic access method. The simulation results indicate that asyn-DCF decrease the packet collision probability and improve the saturation throughput effectively.