Ad Hoc网的IEEE802.11 MAC协议退避算法  

Simulation and Enhancedment of Backoff Algorithm of IEEE802. 11MAC in Ad Hoc

作　　者：苏俊生[1] 戴志平[2] 张雯[2] 

机构地区：[1]空军预警学院研究生管理大队,湖北武汉430019 [2]空军预警学院四系,湖北武汉430019

出　　处：《现代防御技术》2013年第4期100-104,共5页Modern Defence Technology

摘　　要：IEEE802.11的MAC协议是移动Ad Hoc网络目前事实上的标准。节点成功发送后,该协议中的信道接入退避算法将节点竞争窗口值CW(contention window)设为最小竞争窗口值CWmin,这种算法易造成某个节点一直占有信道,使得其他节点出现"饥饿"现象。提出一种改进算法EBEB(enhanced binary exponential backoff),用窗口阀值CWmid区分网络状态,让节点据此来合理的设置当前的竞争窗口,而不是直接设为最小值,避免节点之间产生严重的不公平。仿真结果表明改进算法EBEB在数据丢失量、时延、吞吐量上优于原有的BEB(Binary exponential backoff)算法。The IEEE 802.11 MAC protocol is in fact the current standards for mobile Ad works. If a node has transmitted data successfully , then the backoff should be its min size CWmin Hoc net-in BEB. It causes some nodes always to occupy the shared channel, while the other nodes are in a state of ＂starva-tion＂. Every node is proposed to change its CW according to CWmid ,not directly reducing to its min size. Computer simulation software OPNET is used to validate the algorithm impacting on the data dropped, medium access delay, and throughput capacity. The results show that the ameliorative algorithm has a better performance than BEB.

关 键 词：无线自组织网络 分布式协调功能 退避算法 网络仿真 

分 类 号：TP393[自动化与计算机技术—计算机应用技术]