Enhanced and Optimized Power-Distance Handover Algorithms for High-Speed Trains for WINNER-II Channel Model

Very high-speed trains (HSTs) undergo a significant number of handovers/handoffs between cells. The handover triggering point varies with train speed. This variation causes too late handover triggering, which results in a radio link failure. In this paper, some solutions are proposed to overcome this problem. The first one is an algorithm for triggering handover based on distance, named “Power-Distance” algorithm. Power-Distance algorithm reduces the overall processing power used in handover. For a further improvement, an optimized reward function algorithm is proposed. It is a multi-objective optimization, measurement handover procedure for HST. It uses a reward function to speed up the measurement process when the train is travelling in the direction of the target (destination) cell, with a velocity greater than the normal, to address the train speed changes. Therefore, the probability of too late handover triggering is decreased, resulting in a substantial lessening in the radio link failure probability. Another proposed procedure is the Optimized Power-Distance algorithm. In which, the optimization procedure is applied to the power-distance algorithm.