无线局域网中一种提供服务质量的自适应算法  

A Self-Adaptive Mac Algorithm for Providing QoS on Wlan

作　　者：刘鸿飞[1] 胡九川[1] 李丽君[2] 张宏科[1] 

机构地区：[1]北京交通大学电子信息工程学院,北京100044 [2]重庆工学院,重庆400050

出　　处：《北京交通大学学报》2004年第5期44-48,共5页JOURNAL OF BEIJING JIAOTONG UNIVERSITY

基　　金：国家自然科学基金资助项目(60272010);国家"863"高技术研究发展重大计划资助项目(2001AA121014)

摘　　要：IEEE802.11e在信道负载增加和信道性能恶化的情况下为优先级流提供QoS时,系统性能存在不稳定性.针对该问题提出一种新的自适应MAC算法(MEDCF),站点根据网络中的负载情况和信道的误码率自动调整竞争窗口大小、退避时间及数据帧长度.使信道在不同的负载和变化的信道特性下都能够在稳定系统吞吐量的同时,保证不同优先级数据流对QoS的需求.仿真结果验证了算法的有效性.An adaptive service differenliation scheme for QoS enhancement in IEEE802.11e wireless ad_hoc networks was proposed. EDCF was modified by increasing contention window during deferring periods when channel was busy, and by using an adaptive fast backoff mechanism when channel was idle. The adaptive contention window and packet size were computed automatically. The sheme improves the quality of multimedia applications and increases the overall throughput obtained both in medium and high loading cases. Simulation results show that it is effective.

关 键 词：无线局域网 服务质量 碰撞率 自适应MAC算法 

分 类 号：TN925.93[电子电信—通信与信息系统]