IJSRP, Volume 4, Issue 7, July 2014 Edition [ISSN 2250-3153]
C. Binu Jeya Schafftar
Communication-Based Train Control (CBTC) system is an automated train control system to ensure the safe operation of rail vehicles using data communication. Bidirectional wireless train–ground communications is used to transfer control data between trains and wayside equipment. Wireless local area network (WLAN) based CBTC has impact on train control performance while taking handoff decisions. This may leads to communication interrupt and long latency. Inorder to minimize the handoff latency and to improve the performance, a handoff scheme in CBTC system based on WLANs with multiple-input-multiple-output is proposed. In this channel estimation errors and the tradeoff between MIMO multiplexing gain and diversity gain are considered in making handoff decisions. Handoff decisions and physical layer parameters are optimised to improve the train control performance in CBTC systems. The handoff problem is formulated as a partially observable Markov decision process (POMDP), and the optimal handoff policy can be derived to minimize the handoff latency. The handoff decision and physical layer parameters adaptation problem is formulated as a stochastic control process. Simulation result shows that the proposed approach can significantly improve the control performance in CBTC systems.