Enhancing Communication Availability with Hybrid Networks

Communication-Based Train Control (CBTC) systems have been adopted worldwide to maximize traffic capacity and enforce railway safety. In CBTC systems, wireless communication between trains and the control station is typically realized by homogeneous networks, such as 802.11 WLANs or GSM-R. As a safety-critical application, communication availability is of paramount importance in CBTC systems and is enhanced by component redundancy. We present a novel solution to enhance communication availability in CBTC systems by exploiting heterogeneous networks to provide alternative communication paths. We employ overlay networks over the heterogeneous networks. Experimental results show that overlay networks over LTE networks are an advisable alternative communication path. We design a joint horizontal and vertical handoff decision algorithm which utilizes historical measurements. The proposed algorithm demonstrates effectiveness at reducing number of handoffs, service interruption and low QoS, eliminating ping-pong effects, increasing handoff intervals, and maintaining robustness to partial network failure or degradation.M.A.S.2017-06-21 00:00:0