IEEE802．11 MAC层退避算法的一种改进方案  

An Improved Solution for 802.11 Backoff Algorithm

作　　者：张黎达[1] 刘宗行[1] 李作进[2] 

机构地区：[1]重庆大学通信工程学院,重庆400044 [2]重庆大学自动化学院,重庆400044

出　　处：《重庆工学院学报（自然科学版）》2008年第5期69-72,76,共5页Journal of Chongqing Institute of Technology

基　　金：国家发改委CNGI2005示范工程项目(CNGI-04-4-2D:07-2247)

摘　　要：通过对IEEE 802.11 DCF模式下的马尔可夫链模型的研究发现,目前普遍采用的二进制退避算法存在着由于选择时隙得不到均匀分布而造成竞争节点数量过多时碰撞概率增大、系统吞吐量下降的问题.针对这些问题,提出了一种对部分节点采取延缓其重置进程的方法,其本质就是要通过降低节点对初始窗口的选择概率,来达到退避记数器选择退避数分布均匀的目的.仿真结果表明,该方法能有效地提高系统的吞吐量.When the Markov process of IEEE 802.11 DCF mechanism is studied, it can be found that system throughput decreases and its collision probability increases if the station number increases because the binary backoff algorithm adopted can not provide even distribution for chosen time interval. This paper pro- poses an improved backoff algorithm which adopts the method of deferring the station reset action, so that the distribution of the chosen backoff window is made more evenly by reducing selection probability of nodes for initial windows. Simulation result shows the new method can improve system throughput significantly.

关 键 词：无线局域网 退避 碰撞 

分 类 号：TN919.21[电子电信—通信与信息系统]