基于速度触发的提前切换算法在LTE-R中的应用研究

随着高铁的快速发展，铁路移动通信系统对切换时延、切换成功率等要求更为苛刻。该文针对铁路长期演进(LTE-R)系统提出基于速度触发的提前切换算法，通过提前进行信令交互、设置切换预承载点切换的方式抑制过早或过迟切换所带来的通信中断、掉话等问题。通过信令流程图进行理论分析，并对长期演进(LTE)各结构类型数据计算可知，该算法均可缩短切换时延，其中TDD帧结构类型2时效果最为显著。最后通过仿真对比得到提前切换算法相比传统切换算法有着更高且更稳定的切换成功率，验证算法的有效性，为LTE-R在未来铁路专网的应用提供技术支持。

Advance Trigger Handover Algorithm Based on the Speed in LTE-R

With the rapid development of high-speed railway, the railway mobile communication system has more demands on the handover delay and handover success rate. This paper proposes an advance trigger handover algorithm based on the speed in LTE-R. It is designed to suppress communication interruption and dropped calls caused by that the signaling interaction and setting pre-bearer switching point get rise to handover too early or too late. The theoretical analysis is established in the signaling flow chart, and it is shown that the advance handover algorithm can shorten the handoff latency, which TDD frame structure type two has the most significant time effect. Finally, the simulation shows that compared with the conventional handover algorithm, the advance handover algorithm has a higher and more stable handover success rate. It provides a technical support for the future railway private network applications to LTE-R.