IEEE802.16中一种基于初始退避窗的冲突解决方案

A Collision Resolution Algorithm Based Initial Backoff Window in IEEE 802.16

IEEE802.16在上行链路采用时分多址接入方式,并引入了按需分配多址接入方式用于资源竞争与预留,这使得各用户站(SS)之间存在冲突,导致系统性能下降。本文根据I EEE802.16协议推荐采用的冲突解决算法,利用二维马尔可夫链描述二进制退避算法,分析了吞吐量与延时,并通过归一化处理,定义了代价函数。通过仿真,获得了系统性能达到最优时,最佳初始退避窗口值与用户数的关系。

IEEE 802.16 adopts TDMA （Time-Division Multiple Access） in uplink layer, introducing DAMA（Demand Assignment Multiple Access） at the same time to contention-based reservation of resource. Thus, there are contentions and collisions between SSs （Subscriber Station） and the performance is inevitably deteriorated. In the paper, according to the collision resolution algorithm that IEEE 802.16 recommended to resolve collision, we utilize the description of binary exponential backoff algorithm with the method of planar Markov and analyze the throughput and delay. Also, cost function is defined by transforming throughput and delay. The relationship of optimal initial backoff window and the number of users is obtained by simulation.