Modeling Queueing and Channel Access Delay in Unsaturated IEEE 802.11 Random Access MAC Based Wireless Networks
Modeling Queueing and Channel Access Delay in Unsaturated IEEE 802.11 Random Access MAC Based Wireless Networks
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DOI：
10.1109/tnet.2007.904010
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发表时间：
2008-08
期刊：
影响因子：
--
通讯作者：
Omesh Tickoo;B. Sikdar
中科院分区：
文献类型：
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作者：
Omesh Tickoo;B. Sikdar
本文提出了一种基于IEEE 802.11分布式协调函数（DCF）作为MAC协议的无线网络节点队列延迟和信道访问时间的分析模型。该模型可以考虑任意到达模式、数据包大小分布和节点数量。该模型给出了获得延迟和队列长度特征的封闭表达式，并将每个节点建模为离散时间G/G/l队列。队列的服务时间分布是通过考虑许多因素得来的，这些因素包括由共享介质引起的通道访问延迟、数据包冲突的影响、产生的回退以及数据包大小分布。该模型还扩展到正在考虑的802.11e提案，其中一旦通道被访问，可能会在突发中传输许多数据包。我们的分析结果通过大量的模拟得到验证。我们模型的结果还可以用于提供服务质量的概率保证，并确定在满足给定延迟约束的情况下可以容纳的节点数量。
In this paper, we present an analytic model for evaluating the queueing delays and channel access times at nodes in wireless networks using the IEEE 802.11 Distributed Coordination Function (DCF) as the MAC protocol. The model can account for arbitrary arrival patterns, packet size distributions and number of nodes. Our model gives closed form expressions for obtaining the delay and queue length characteristics and models each node as a discrete time G/G/l queue. The service time distribution for the queues is derived by accounting for a number of factors including the channel access delay due to the shared medium, impact of packet collisions, the resulting backoffs as well as the packet size distribution. The model is also extended for ongoing proposals under consideration for 802.11e wherein a number of packets may be transmitted in a burst once the channel is accessed. Our analytical results are verified through extensive simulations. The results of our model can also be used for providing probabilistic quality of service guarantees and determining the number of nodes that can be accommodated while satisfying a given delay constraint.