LTE-R Handover Point Control Scheme for High-Speed Railways

LTE-R is a new standard under development to serve future high-speed railway systems (HSRs) with reliable real-time train control and management system support as well as passenger safety, convenience, and infotainment services. The QoS of LTE communications is significantly degraded in HSRs due to rapid channel variations that exceed the variation range of LTE systems, resulting in delayed handover or handover failure due to radio link failure. Therefore, a handover decision scheme optimized for HSRs to ensure the QoS requirements for communications is necessary. In this article, a new H2 scheme for HSRs is proposed, which improves the handover performance of high-speed moving LTE systems. The H2 scheme monitors the reference signal received power variation level of the serving evolved node B and handover target evolved node B to prevent late handover and stably execute handover in rapidly changing conditions. Simulation results demonstrate that the proposed H2 scheme can significantly lower the handover failure probability for HSRs compared to the handover schemes currently used in LTE.