RWBO＋BEB： A Novel Backoff Algorithm for IEEE 802.11 DCF  

作　　者：LI Yun ZHAO Weiliang LONG Keping YANG Fengrui 

机构地区：[1]Special Research Centre for Optical Internet ＆ Wireless Information Networks, Chongqing University of Posts ＆ Telecommunications, Chongqing 400065, China [2]National Defense Key Laboratory of Anti-Interference, Communication Technology, University of Electronic Science and Technology of China, Chengdu 610054, China [3]School of Electronic Engineering, Beijing University of Posts ＆ Telecommunications, Beijing 100876, China

出　　处：《Chinese Journal of Electronics》2005年第4期686-690,共5页电子学报（英文版）

基　　金：This work is supported by the National High Technology Development 863 Program of China （No.2003AA121540）; the National Natural Science Foundation of China （No.90304004）; the research grants by the Ministry of Education of China （No.204125）; the Science and Technology Research Project of Chongqing Municipal Education Commission of China （No.050310）; the research grants by the Ministry of Personnel of China.

摘　　要：The packet collision probability of 802.11 DCF is very high on saturated channel condition, which is attribute to that the PDoSS of 802.11 is uneven. In this paper, we propose a novel random backoff algorithm, called RWBO＋BEB, by which the packet collision probability of 802.11 DCF can be significantly decreased. The basic idea of RWBO＋BEB is that the backoff timer is decremented by aSlotTime with probability Pd if the channel state is idle, and the contention windows are Exponentially increased if a transmission fails. A Markov model is built for analyzing RWBO＋BEB＇s PDoSS and throughput on condition that the channel is saturated. The performance of RWBO＋BEB is also evaluated by simulation in terms of PDoSS, saturation throughput, and packet collision probability. The simulation results indicate that RWBO＋BEB candecrease the packet contention probability to a large extent, and utilize the channel more efficiently compared to 802.11 DCF. Moreover, we analyze the relation of saturation throughput and packet collision probability to walking probability （Pd） and contention windows （w）, respectively. The analysis indicates that RWBO＋BEB has a remarkable feature： the throughput changes little and the collision probability keeps low （under 0.1） in a large range of pd and w, thus allows us to configure Pd and w more flexibly.

关 键 词：802.11 Distributed coordination function （DCF） Random walking back Off Binary exponential backoff Markov chain mode 

分 类 号：TN925.93[电子电信—通信与信息系统]