为实时业务提供QoS保证的MAC机制性能研究  

Performance Research of MAC Mechanism providing QoS Guarantee for Real-Time Traffic

作　　者：白翔[1] 毛玉明[1] 

机构地区：[1]电子科技大学通信与信息工程学院,四川成都610054

出　　处：《现代传输》2007年第6期62-65,共4页Modern Transmission

摘　　要：分析的MAC机制在IEEE802.11DCF机制的基础上提供了QoS增强。由于实时业务对时延要求敏感,因而提出的实时业务分析模型并未考虑退避重传,和尽力而为业务相比较。实时业务获得了高的饱和吞吐量和低的接入延时,但是以较高的帧丢失率为代价。为了保证实时业务的QoS要求,使用QoS参数P_(0,Qos)来限制帧丢失率。经过分析得出,在保证帧丢失率上限和最大吞吐量的条件下,可求得最优初始窗口,获得较好的网络性能。The analyzed MAC mechanism is based on Distributed Coordination Function（DCF） in IEEE802.11 and contains quality of service （QoS）.In the proposed priority analytical model, retransmission is not used for the real-time traffic, because the real-time traffic is sensitive to the delay. Compared with the best-effort traffic, the real-time traffic has a much better saturation throughput and much less saturation access delay. But the cost is the higher frame-dropping probability for the real-time traffic. To guarantee quality of service（QoS） of the real-time traffic, the paper puts forward a QoS parameter P0.Qos to limit frame-dropping probability. After the analysis of results, we can conclude that a optimal backoff window size will be acquired in accord with QoS guarantee and the maximum throughput to implement good performance of MAC mechanism.

关 键 词：DCF EDCF 退避重传 饱和吞吐量 接入延时 帧丢失率 

分 类 号：TP393.02[自动化与计算机技术—计算机应用技术]