Abstract: When the speed optimization algorithm improves the success rate of switching in high-speed railways, the problem of sharp increase of ping-pang trigger probability exists. To solve this problem, an optimized handover algorithm based on location is proposed by analyzing the influence of hysteresis and location on the ping-pang trigger probability and handover success probability. A subtraction function relationship is established between the hysteresis and the terminal location in this algorithm. The problem of increasing the ping-pang trigger probability or reducing the switching success rate when using the same hysteresis margin in different location of overlapping area is solved by use of the hysteresis decreasing with the increase in distance between terminal and source base stations. The simulation results show that, compared to speed optimization algorithm, the proposed handover algorithm based on position information can improve the switching success rate while avoiding the increase of ping-pang trigger probability.

Key words: high-speed scenario, wireless handover, hysteresis margin, handover success probability, ping-pang trigger probability

摘要： 高速场景下速度优化算法在提高切换成功率的同时，存在乒乓切换触发率急剧增加的问题。为了解决这一问题，通过分析迟滞余量和切换位置对乒乓切换率和切换成功率的影响，提出高速场景下基于位置信息的切换优化算法。该优化算法将迟滞余量与终端位置建立一次减函数关系，利用迟滞余量随终端远离源基站呈递减的趋势，解决在重叠带不同位置使用相同迟滞余量时所引发的乒乓切换触发率提高或切换成功率降低的问题。仿真结果表明，所提出的基于位置信息的切换优化算法与速度优化算法相比，可以实现在提高切换成功率的同时避免乒乓切换率增加。

关键词: 高速场景, 无线网络切换, 迟滞余量, 切换成功率, 乒乓切换触发率