一种改进的无线局域网DCF算法——OBS_MCP  

Improved on DCF for wireless local area networks—OBS_MCP

作　　者：何强[1,2] 陈益强[2] 纪雯[2] 

机构地区：[1]湘潭大学信息工程学院,湖南湘潭411105 [2]中国科学院计算技术研究所,北京100080

出　　处：《微计算机信息》2010年第33期115-117,101,共4页Control & Automation

基　　金：国家"863"高技术计划项目(2007AA01Z305);北京市教育委员会共建项目

摘　　要：在对标准的802.11DCF研究的基础上,提出了一种基于最小碰撞概率下的最佳退避时间选择算法(Optimal Backofftime Selection Algorithm based on Min-Collision Probability,OBS_MCP)。标准的IEEE802.11DCF机制采用二元指数退避算法(Binary Exponential Backoff algorithm,BEB),该算法在无线网络节点增加的情况下,容易发生碰撞,从而使网络性能急剧下降。OBS_MCP算法中,每个节点通过获得网络中其他节点退避计时器中剩余的退避时间来选择一个竞争信道的最佳退避值,而不是采用标准IEEE802.11DCF机制中在竞争窗口中随机选择退避时间的方法,这样在有效避免了冲突的情况下使网络达到最佳的吞吐量。最后通过NS-2仿真实验证明了OBS_MCP算法比采用标准的IEEE802.11DCF机制的网络吞吐量有很大的提高。On the deep research of the standard 802.11 DCF, we have proposed an Optimal Backofftime Selection Algorithm based on Min-Collision Probability （OBS_MCP）. The standard IEEE 802.11DCF mechanism has adopted the Binary Exponential Backoff Algorithm （BEB）, and on condition that the wireless network nodes are increasing, this algorithm suffers from frequent packet collisions so as to sharply decrease the network performance. The OBS_MCP can make each node obtain the remaining backoff time of other nodes＇backofftimers in the network to select the optimal backoff value for competing channel, instead of using the standard IEEE 802.11DCF mechanism to select backoff time randomly in competition window so as to achieve the best network throughput without collision. At last, the result of NS-2 simulation experiment show that OBS_MCP would have greatly improved throughput than the standard IEEE 802.11DCF mechanism.

关 键 词：DCF 退避计时器 冲突避免 网络吞吐量 竞争窗口 NS-2 

分 类 号：TP393.17[自动化与计算机技术—计算机应用技术]