A seamless dual-link handover scheme suitable for high-speed rail

LTE with large capacity and high speed is the most promising standard of wireless data communications technology to be used in Chinese high-speed rail(HSR). Because of over-frequent handover in HSR, the experience of passengers is highly degraded. Wireless Quality of Service (QoS) provisioning in such high speed movement is more difficult to be tackled than in a fixed-wired environment. Seamless handover attempts to provide a given QoS during the process of migration from one cell to another. It can reduce the interruption period to nearly zero. In this paper, we revised an existent seamless dual-link handover scheme where the Train Relay Station relays the data of users in the train and two antennas are mounted in the top of the train and designed a set of new handover procedures suitable for HSR communications. We defined a velocity threshold(VT). If the speed of train exceeds VT, two target base stations are prepared for user equipment(UE) when handover is triggered. The simulation results show that in the proposed scheme the communication interruption probability is under 0.01 when the train is at speed of 350 kilometers per hour.