随机多址接入概率检测函数控制CSMA协议分析

【作者】 吴亮；

【导师】 何敏； 赵东风；

【作者基本信息】 云南大学 ， 电子与通信工程， 2012， 硕士

【摘要】 随着无线通信技术的广泛应用,传统局域网络已经越来越不能满足人们的需求,于是无线局域网(WLAN)应运而生,且发展迅速。在无线局域网中,网络设备通过无线信道来实现彼此之间的正常通信。因此,WLAN网络能够用简单的存取架构使网络用户的信息范围得以延伸,从而达到通信的移动化、个性化和宽带化。尽管目前无线局域网还不能完全独立于有线网络,但近年来无线局域网的产品逐渐走向成熟,正以它优越的灵活性和便捷性在网络应用中发挥日益重要的作用。在卫星通信、计算机通信、移动通信等众多现代通信网络中,网络实际登记的用户数目往往要比同一时刻实际请求服务的用户数量大得多。由于公共信道数量有限,当无线局域网中的多个用户与其他用户进行通信时,难免会对同一个信道进行竞争占用。这时,为解决这种情况造成的网络拥堵,我们必须采用随机多址技术。本文对现有的随机多址技术和基于随机竞争的无线局域网通信协议进行了一定的分析,并在概率检测函数控制随机多址通信接入CSMA无线局域网通信协议的基础上,采用平均周期的分析方法,定义每个传输周期为TP,将信息分组的传输周期TP进行划分,即信息分组发送时间1、信息分组传输线路延时时间α、ACK信息时间τA三部分,对整个周期TP内到达的所有信息分组都以p概率检测函数控制的方式接入信道。在终端节点,到达的信息分组以概率值p持续侦听信道,以概率(1-p)放弃侦听信道,通过选取不同的概率p值动态控制休眠节点数目。本文以此为切入点,提出了随机多址通信接入CSMA无线局域网通信协议的改进分析,并对其性能进行仿真验证,说明其有效性。论文共分为五个章节：第一章,主要介绍了论文课题的研究背景,对无线局域网的相关理论知识和协议标准进行了详细说明。通过对课题研究工作的简要阐述,强调了本课题研究的目的和意义,概括地叙述了全文的主要内容和创新性。第二章,介绍随机多址通信接入协议的相关知识,对概率检测函数控制的CSMA无线局域网通信协议的工作原理进行认真分析。第三章,简要描述基于概率检测的无线局域网随机多址通信接入通信协议的相关内容,并对该协议模型进行分析,对协议吞吐量等性能指标进行理论推导。第四章,深入了解协议的工作原理及机制,通过仿真实验对文中的理论推导进行验证分析。第五章,总结全文研究工作和成果,对研究过程中存在的不足和缺陷进行反思,并对今后课题的深入研究做出展望。全文紧紧围绕随机多址通信接入CSMA无线局域网通信协议这一研究课题,对其发展现状和应用前景做了简要说明,并在现有协议基础上做了相关改进。更多还原

【Abstract】 With the wireless communication technology has been widely used, people can not be satisfied with traditional local area network, and then a new communication method appeared, it is named wireless local area network or WLAN and developing with a high speed. In the wireless local area network, network equipment realizes the normal communication between each other through a radio channel. Therefore, the scope of users obtaining information is expanded by the simple access architecture in the WLAN, and then the communication service can get mobility, personality and broadband features. Although at present the WLAN can not independent of the cable network completely, but the products of WLAN is maturing gradually in recent years. Because of their excellent flexibility and convenience, these products are playing an important role in the network applications increasingly.The number of registered users is more than the number of who apply for network services frequently in many modern communication network like satellite, computer, mobile and so on. Because of the restrictions on the quantity of public channel, users have to compete to use the same channel when they need to communicate with others in the WLAN. The competition would cause network congestion. In order to solve this problem, we must use a random multi-access technologies.In this paper, the author analyzed the random multiple access technology and communication protocol based on the random competition in the wireless local area network. It was controlled by a probability function what communication protocol of random multi-access communication access CSMA in the WLAN. Using the analysis method of the average period, a transmission cycle was defined as the TP, and the TP of information group was divided into three parts. They are time of sending information group, delay time in transmission lines, and time of produce ACK information. Their length were1, a and τA.The information packets access channels with testing way of p probability function which arrived in the cycle of TP. In the nodes, the information packets keep watch on channel with probability value of p, or give up with probability value of (1-p). The number of dormancy node will be controlled by choosing different p value. Based on this starting point, the paper put forward an improved analysis of communication control protocol based on random multi-access communication access CSMA for WLAN, and verified the performance with the simulation experiments to prove its effectiveness.The thesis is divided into five chapters:The first chapter mainly introduced the research background, and illustrated theory knowledge and protocol standards related to the wireless local area network in detail. The article also expounded on this subject’s research briefly, emphasize the subject research of purpose and meaning, generally describes the main contents of the full text and innovative.The second chapter introduced the knowledge of random multi-access communication access CSMA, and analyzed the principle of communication protocol in WLAN with probability function detection.The third chapter described contents of communication protocol for random multi-access communication access CSMA based on the probability of detection in WLAN briefly, analyzed the protocol model, and got some properties like throughput with logic reasoning.Chapter IV, there are some simulation experiments about the theory of protocol in the article. These experiment show the correctness of the analysis and reasoning in this paper.Chapter V is the summary of the paper. The writer rethink how to solve the problems and defects in the course of the study, and made a outlook of re search in the future.The paper’s topic is communication protocol based on random multi-access communication access CSMA for WLAN. It explained its development present situation and application prospects, and improved the existing protocol.更多还原