有限负载下大规模无线CSMA网络的性能分析与优化

项目名称： 有限负载下大规模无线CSMA网络的性能分析与优化

项目编号： No.61202459

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 计算机科学学科

项目作者： 开彩红

作者单位： 合肥工业大学

项目金额： 23万元

中文摘要： 作为解决宽带接入"最后一英里"的主流技术之一，WLAN已被广泛应用于人们的工作和生活中。多个物理位置相邻的WLAN按照802.11 DCF机制参与竞争信道，组成大规模的无线CSMA网络。如何分析、理解和优化这类CSMA网络一直是学术界的热点话题。 本课题拟在饱和状态下无线CSMA协议研究的基础上，运用等效链路接入竞争强度法和等效网络冲突图加权叠加法建立有限负载下CSMA网络的数学模型，将链路发送队列为空的状态纳入分析范畴，探讨链路间相互影响和作用的随机过程，理解负载控制和协议参数设置对网络性能的影响；运用置信传播算法，提供链路吞吐量的快速估计算法。更进一步，在最优化理论的框架下，设计通过调整给定负载和CSMA协议参数来实现系统效益最大化的分布式算法。 本课题的研究将建立起一套分析和优化有限负载下无线CSMA网络的理论和算法，为无线网络规划提供参考工具，为优化WLAN提供理论基础和算法支持。

中文关键词： 无线网络；载波侦听多路接入；网络编码；网络体系结构；网络协议性能分析

英文摘要： As one of the key technology for solving the Last-Mile communication problem, WLAN has been widely deployed in our daily life. Numerous co-located WLANs compete with each other for the shared medium according to the IEEE 802.11 DCF mechanism, constituting a large-scale wireless CSMA network. How to analyze, understand and optimize this CSMA network has been a "hot topic" among researchers during recent years. First, this proposal attempts to develop an analytical model for the large-scale wireless CSMA network with unsaturated traffic load. Based on our prior research on saturated CSMA network, we will propose two methods, Equivalent Link Access Intensity and Weighted Summation of Equivalent Network Contention Graph, to model the unsaturated CSMA network. Different from most prior work, we take the status of the link transmit buffer into account while analyzing the interactions among links, and study how the offered-load and protocol-parameter settings impact the network performance. Second, we design quick and simple computation algorithms based on Belief Propagation to calculate the throughput distribution of links. Third, under the framework of the optimization theory, we design distributed algorithms to achieve the optimal system utility, by incorporating the adaptations of the offered-load and the paramete

英文关键词： Wireless Networks；Carrier Sense Multihple Access；Network Coding；Network Architecture；Performance Analysis of Network Protocols