Development and Application of LTE-M Wireless Train Access Unit in CBTC System

The stability of urban rail transit vehicle-ground integrated communication system is one of the biggest problems faced by metro operatings. In order to improve the security and reliability of communication, the wireless vehicle-ground communication technology of urban rail transit has been upgraded from WLAN to long-term evolution technology(LTE). On the basis of comprehensive analysis of the LTE technology of urban rail transit vehicles, a train access unit for the LTE-M wireless private network vehicle-ground communication equipment is proposed, according to the requirements specification of urban rail transit vehicle-ground integrated communication system. It adopts 1.8 GHz TD-LTE proprietary mobile network and VPN security access technology to establish a secure and reliable communication link at the vehicle-ground end. Through the communication beating test, the train access unit can communicate with the ground server through the core network of the private network, the communication rate is stable, the delay is less than 150 ms and no packet loss phenomenon appears. It can meet the data access service requirements of carrying CBTC control service, passenger information system, video surveillance system, etc.