Key Technology Research Of Train-To-Wayside Wireless Communication Of Modern Tram

Nowadays, cars account for a large proportion in Chinese urban transit tools, which can lead to many problems, such as traffic jam, environmental pollution, etc. To solve these problems, modern trams are widely used in the world with its large capacity, safety and comfort, energy saving and environmental protection, quick and convenient. Train-to-wayside wireless communication system, which works as an important component of Modern Tram Operation Control System, is vital to the safety and running efficiency of tram. Operation control center could achieve the following tasks: overall monitoring the operation status of modern tram and failure warning. Therefore, the research of modern tram train-to-wayside wireless communication system and establishing such a real-time, reliable and stable system have an important significance.Aimed to the real-time and reliability of train-to-wayside data transport, the research goal of this paper is to study the framework of train-to-wayside wireless communication system, to achieve the wireless communication system based on GPRS wireless network and TCP communication protocol and to formulate the reliable data transport mechanism.Firstly, the common network linking method of train-to-wayside wireless communication system of modern tram is analyzed. After compared, GPRS, which is more suitable for this system, is selected and the overall framework of communication system is built.Then, the hardware and software of on-board communication platform and ground communication platform are designed and analyzed respectively. The on-board device is consisted of control unit, wireless communication module, positioning module, storage module and display module. The ground communication platform is consisted of Socket communication server software based on TCP and WEB. To improve the reliability and timeliness of data transmission in further, the reliable data transport mechanism during the communication process is proposed and the packet format is formulated according to the private protocol. Two SIM900 A modules are used to establish dual-redundant TCP connection with TCP server. The transport response mechanism and dual-redundant method using TCP Socket and Http Post are formulated. When the TCP server broke down, the PHP page in certain website can work as the interface to receive the data.Finally, the system is tested and the results display that data transmission is stable and reliable. The probability of error and delay is within the allowable range. The reliable data transport mechanism effectively improves the reliability and timeliness of train-to-wayside communication system.