A novel communication-based train control (CBTC) system with cooperative wireless relaying

Communication-Based Train Control (CBTC) system is an automated train control system using bidirectional train-ground communications. Most existing CBTC train-ground communication systems work in the infrastructure mode without train-train communications. Due to unreliable wireless communications and frequent handoff, existing CBTC systems can severely affect train control performance. In this paper, we use recent advances in cooperative relaying to enable train-train communications, and consequently enhance the train control performance of CBTC systems. Linear quadratic cost for the train control performance in CBTC systems is considered as the performance measure. We jointly consider cooperative relaying and handoff decision issues in CBTC systems. Moreover, in order to mitigate the impacts of handoff latency on the train control performance, we propose an optimal guidance trajectory calculation scheme that takes full consideration of the tracking error caused by handoff latency. Simulation result shows that the train control performance can be improved substantially in our proposed CBTC system.