The Research of Soft Handover Signaling for LTE System in High-Speed Railway Environment

Hard handover (HHO) algorithm has been used for LTE system according to 3GPP specifications. In this paper, a soft handover (SHO) signaling procedure is investigated to validate the feasibility of SHO algorithm for LTE system so as to solve high handover failure ratio in high-speed railway environment. The paper gives an overview of SHO signaling procedure, SHO algorithm and simulation approach for LTE system. The simulation is implemented to select different handover parameter sets for HOM (Handover hysteresis margin) and TTT (Time-to-Trigger), which is investigated the influence to Ping-Pong handover and radio link failure (RLF) in 350 km/h for the high-speed railway simulation scenario. The results suggest that SHO algorithm has better handover performance than A3 event HHO algorithm in 350 km/h.