基于IEEE 802.11协议的P概率退避算法研究

A novel P-Persistent backoff algorithm in IEEE 802.11 protocol based on probability P

针对IEEE 802.11 DCF提出一种P概率退避算法P_PBA(P-persistert backoff algorithm)。P_PBA基本思想是网络终端执行退避算法时计算出时隙利用率和概率P,在终端每次成功发送后,终端的发送竞争窗口大小以概率P回到初始值,否则以概率1-P保持竞争窗口大小不变。P_PBA解决了IEEE 802.11协议没有记录网络竞争程度问题,有效地降低碰撞概率,提高网络性能。仿真结果表明。

A novel P-Persistent backoff algorithm（P_PBA） is proposed to improve the binary exponential backoff algorithm of IEEE 802.11 DCF protocol. The basic principle of P_PBA is to compute slot utilization and probability P when network terminal executes backoff algorithm. After successful transmission, P_PBA can decrease the contention window size to the minimal value with probability P. Otherwise P_PBA keeps the contention window. P_PBA adapts the contention window to the contention level in current IEEE 802.11 network, and therefore it decreases the collision probability effectively and improves the network performance. Simulation results indicate that P_PBA can offer a higher throughput while improving the frame delay.