A Wireless Subway Collision Avoidance System Based on Zigbee Networks

A wireless subway collision avoidance system based on zigbee network is proposed in this paper. In the proposal, all the zigbee nodes are divided into two types, fixed nodes and mobile nodes. The fixed nodes are deployed in tree topology networks overlapped with each other along the subway tunnel; the mobile nodes are installed on the trains. The core idea is as soon as a fixed node establishing an association with a mobile node, the fixed node broadcasts the event with MAC address of the mobile node immediately. By listening the broadcasted messages, other nodes can deduce position of the mobile node currently being associated. In such a way, the overlapped zigbee networks can locate positions, detect abnormal stop of trains and broadcast these information to other trains in the tunnel. With each train knowing position of the train ahead of it, the collision can be avoided. The proposed zigbee network system is evaluated by ns-2, simulation results are presented. Index Term—wireless network, zigbee, train collision avoidance