A Sensor-Based Seamless Handover Solution for Express Train Access Networks (ETANs)

Express train transportation is becoming a major tool for carrying approximately one million passengers daily in China today. To provide broadband information services for train passengers, the greatest challenge is achieving a seamless handover solution to guarantee wireless service continuity. This motivates us to incorporate sensor technology into Radio over Fiber architecture to construct an Express Train Access Network (ETAN), where the deployed sensor network captures the train movement status, which can indicate the wireless signal strength. Since the train moves on a fixed rail with fixed direction, it is possible to form an intelligent handover decision system, in which a critical movement state can exactly trigger an optical switch unit in the central station to carry out the handover procedure. Theory analyses and simulation results demonstrate that the proposed architecture can perform handover within 22 ms at a train speed of 350 km/h, providing wireless services for users without disruption, even for a cell radius as small as 100 m.