地铁无线AP信号质量监测方法研究
摘要：随着无线通信的迅速发展，无线通信在我们的轨道交通中扮演着举足轻重的角色。从ATC（Automatic Train Control）的列控系统一直演变成现在基于通信的CBTC（Communication Based Train Control）列控系统。CBTC列控系统主要运用于我们城市的轨道交通，它能够让远程监控设备得到列车的车次号、运行状态等信息。本文主要研究上海地铁11号线、2号线列车与站台AP（Access Points）无线通信的过程，站台AP设备采用IEEE 802.11无线通信技术，工作频段在2.4GHz。利用Commview以及Wirelessmon软件对无线信号的监测并捕捉列车与站台AP之间数据报文交换，研究它们所产生的数据报文的类型及特点，提出一个可以监测地铁无线AP信号质量的方法，其主要目的是可以提供一种准确有效对于一些故障AP的及时处理，消除一些安全隐患，能够降低维护的盲目性并提升运营的安全性。63495
毕业论文关键词：无线通信；地铁；AP；捕获数据包；802.11
THE RESEARCH OF MONITOR METHOD IN METRO WIRELESS AP SIGNAL QUALITY
Abstract：With the rapid development of wireless communication, wireless communication in our rail transit plays a pivotal role. From the Automatic Train Control has been evolved into theCommunication Based Train Control. Communication Based Train Control system is mainly used in our city rail transit, it can let the remote monitoring equipment to get train number, running status and other information. This paper mainly studies the process of wireless communication between Shanghai Metro Line 11、Line 2 and AP (Access Point). The AP equipment adopts IEEE 802.11 wireless communication technology, and working band is 2.4GHz. Using Commview and Wirelessmon software to monitor the wireless signal and capture the train and the station AP data, we study the type and characteristics of the data packets generated by them, and propose a method to monitor the quality of the wireless AP signal. The main purpose is to provide an accurate and effective method for some faulty AP timely processing, to eliminate some security risks, can reduce the blindness of maintenance and enhance the safety of operations.
KeyWords：wireless communication;metro;AP;packet capture; 802.11;
目录
1 绪论 1
1.1 课题的目的和意义 1
1.2.1国外研究现状与水平 1
1.2.2国内研究现状与水平 2
1.3 发展趋势 2
1.4研究内容及论文组织结构 2
1.4.1 研究内容 2
1.4.2组织结构 3
2 站台通信设备及所用协议 4
2.1 站台AP设备 4
2.2 802.11协议 5
2.2.1 802.11协议建立连接的方式 6
2.2.2 802.11中的帧格式 6
2.2.3 Wi-Fi认证过程 7
3 列车与站台AP通信过程 9
3.1捕捉通信报文 10
3.1.1捕捉报文工具 10
3.1.2 列车进站的状态 11
3.1.3 区分所需要的报文 11
3.2 列车与站台通信的特征 14
3.3 列车与站台的通信过程