IEEE 802.11无线局域网性能分析

【作者】 翟临博；

【导师】 张晓敏；

【作者基本信息】 山东大学 ， 通信与信息系统， 2007， 硕士

【摘要】 近年来，由于无线局域网具有使用方便，组网迅速，以及高可靠性等优点，因此得到了飞速的发展。人们对无线局域网的研究也就成为了近年来网络研究中的一个热点。由于IEEE 802.11无线局域网采用无线信道进行数据传输，因此会产生冲突以及各种干扰。为了解决无线信道对数据传输带来的问题，局域网采用了载波监听多路访问机制，但是这种机制引入了很多额外的控制帧。这些额外开销的出现，使人们更加关心802.11局域网实际的吞吐量性能。因此出现了很多分析局域网性能的数学模型。本文从分析802.11无线局域网性能的基本模型入手，在深入分析现有的各种数学模型的基础上，针对它们的不足，利用条件概率和马尔可夫链的数学工具，提出了一种改进的在非理想信道条件下分析无线局域网饱和吞吐量性能的数学模型。这个模型考虑了信道“捕获”和退避“冻结”等问题，同时采用条件概率建立了数学模型。在IEEE 802.11b无线局域网定义的不同数据速率下，利用该模型对基本访问机制和RTS／CTS访问机制进行了分析。该模型适用于理想和非理想信道下各种不同传输速率的802.11无线局域网的性能分析。仿真表明该模型的计算结果精确，并与仿真结果相吻合。更多还原

【Abstract】 In the recent years, Wireless Local Networks (WLANs) have a rapid development of their convenience, quickly establishment and high credibility. These advantages make the research on Wireless Local Networks become an important part in the fields of networks. Because of data transmission of IEEE 802.11 WLANs using a wireless channel, collision and interference are not avoidable. WLANs use a carrier sense multiple access mechanism, which leads to more control frames, to solve the problems brought by a wireless channel. Because of the overhead, people are interested in the real throughput performance of 802.11 WLANs. Then many analytic models appear.We compared and analyzed the analytic models which had appeared comprehensively. To overcome the disadvantages of these models, we propose a improved model to estimate the saturation throughput of IEEE 802.11 for a lossy channel. This model, involved in capture effects and backoff freezing procedures, is based on elementary conditional probability arguments. Then the paper uses this model to analyze the performance of the basic access and RTS/CTS access mechanisms of IEEE 802. 11b.This model, with different data rates, applies to both ideal channel and lossy channel conditions in performance analysis of IEEE 802.11 WLANs. Simulation results show that the analysis accurately predicts the saturation throughput.更多还原