Application Research Of The WLAN In Metro CBTC

With the rapid development of large urban metro, signal system is undoubtedly the brain and the core of the whole subway system, moving block system is the development direction of the signal system, the application scale is also growing. Moving block signaling system is mainly based on the wireless communication technology of the train control system(CBTC), the CBTC system in radio communication technology and automatic control technology in one, using the high accuracy of train positioning(does not depend on the track circuit), bidirectional continuous, high capacity of vehicle data communication and vehicle and ground security function processor implementation of a continuous automatic train control system, realize the use of rail cable, leaky cable and wireless technology or their combination of.Most of the communication technology of CBTC is used in the WLAN 2.4G network structure. On the other hand, with the introduction of 2G, 3G, 4G mobile signal in Guangzhou Metro and the rapid development of mobile technology, 3G to MIFI, i Beacon and other 2.4G devices more and more. The subway as a mileage of hundreds of kilometers, the huge underground space of huge traffic, the mobile phone signal coverage is more prominent. 2G mobile communications signal has been achieved in the domestic three operators within the scope of the Guangzhou Metro extension and coverage, including mobile GSM900 signal, China Unicom GSM900 signal and CDMA800 signal[1]. Provincial and municipal departments have repeatedly issued a document to accelerate the construction of The Metro 3G. Since the end of 2011, The Metro Inc and China Unicom, China Mobile and other units jointly set the subway 3G construction.Based on this background, this paper analyzes the characteristics of WLAN system structure and signal system based on CBTC and CBTC system based on the CBTC signal system in The Metro. At the same time, this paper describes the 2.4G frequency band equipment introduced by The metro, through a large number of field survey, literature search, field data and other research, combined with the The Metro signal system equipment status, from the experimental test data, the introduction of 2.4G frequency band signal system and the impact of the device, focusing on packet loss rate, delay and other aspects of CBTC. Finally, according to the theoretical calculation, test data analysis and research results, this paper summarizes the application value of WLAN in Metro CBTC, and puts forward some improvement suggestions and prospects, which provides data support and test experience for the promotion of WLAN in Metro CBTC.