Subway Passenger Information Display System In The Wireless Communication Transmission Stability Study

The function orientation of Passenger Information Display System(PIDS) is providing the operation and security /anti terrorism information, as well as some subway public service advertising and real time information such as weather ,news and transportation information. In the event of emergency, the highest priority of this system is display of emergency rescue messages and real time information of train monitoring images. Therefore, subways in the country are speeding up delivery of various information, enforcement of operation and management efficiency and expansion of the service scope of subways, in order to increase the service quality for passengers. Meanwhile, the county is increasing the investment to add PIDS systems and realize the effective monitoring of safe conditions of trains through the monitoring system of train carriage and driver's cab.Generally, through Ground Wire Network and Train to Ground Wireless Transmission network, PIDS of subways deliver operation information and other video information( such as entertainment ) to streaming media computers in network of train, then delivers the information to passengers through vehicle display terminals, providing passengers with an information service system.Due to the high speed moving nature and in order to ensure the effective broadcasting of real time information, the requirement for stability, timeliness and wireless switching speed of Train to Ground Wireless Communication Transmission is very high. Moreover, most subway signaling system communication transmission are using Communications Based Train Control (CBTC) technology as most subways are underground where the scope is small and it covers a lot of professional fields. These two systems are using the same band spectrum, resulting the jamming problem between them. All these situations and problems have affected the stability and quality of wireless transmission of PIDS systems.Currently, the major wireless communication transmission technology includes: 1) WLAN, WImax,Mesh and TETRA digital trunking communication method; 2) digital video broadcast communication method; 3) TRainCom, ect. This article aims to research and compare the technique parameters and the calculation and price of wireless broadband of these 6 wireless transmission methods, so as to obtain the best usage and solution.According to the result of analysis and technique comparison, we know that the WLAN technology help realize the high speed and bidirectional communication between the subway train and ground, so as to meet the data transmission need of trains during the course of the high speed moving to the highest extent. Under existing technology condition, this is a train to ground wireless and real time multi media information transmission method that features advancement, timeliness and credibility in subway system.Lastly, this article will also details the construction program, deploying program of interzone wireless base station, wireless communication switching program and anti jamming program of X line of W subway.