IEEE802.11e无线局域网中的接入延迟分析模型

IEEE802.11e标准为各个服务类别制定了不同的信道竞争参数数值,使得无线局域网具备了业务区分能力。标准中所提出的增强型分布式接入方式主要包括虚拟碰撞、节点回退、最小竞争窗口以及仲裁帧间隔等机制。本文建立三维离散马尔可夫模型分析队列在接入过程中的竞争行为,进而准确估计各个队列的接入延迟。仿真结果表明,该模型能够准确地描述资源竞争情况,接入延迟计算法方法可根据不同系统参数精确地计算接入延迟性能。

Analysis Model of MAC Access Delay in IEEE 802.11e Wireless LAN

The new IEEE 802.11e standard is specified to support service differentiation in wireless local area networks(LAN),and different contention parameters are designated to each type of service.The Enhanced Distributed Channel Access(EDCA) proposed in this standard mainly includes virtual collision,backoff procedure,minimum contention window and different arbitration interframe space(AIFS).This paper establishes 3D-DEM Markov Model to analyze the delay performance of differentiated service traffic,then put forward a recursive method capable of calculating the mean access delay.Simulation results show that this model could describe the contention performance accurately and the recursive method could calculate the access delay precisely according to different parameters.