移动终端异系统间切换的改进

在5G网络建设初期, 相比于4G网络的全面覆盖来说, 5G网络的覆盖并不完善, 所以5G终端会频繁在两种网络之间进行切换, 如果终端只是快速经过5G网络的覆盖范围, 那么终端将会执行两次不必要的切换流程, 造成信令和电量的浪费。在分析了移动终端协议栈非接入层的信令流程之后, 提出了采用延迟切换的方法来控制终端进行网络切换, 在切换到5G网络之前先要等待一段时间。对延迟切换方法进行建模和仿真可以发现, 所提方法在有效减少切换次数的前提下，也能保证用户体验质量。通过分析, 给出了如何设置延迟时间的大小能使延迟切换策略的收益更大。

Improvement of handover between different systems of mobile terminals

In the early stage of 5G network construction, compared with the comprehensive coverage of 4G network, the coverage of 5G network is not wide enough. In that case, 5G terminals will frequently switch between the two networks. If the terminals only pass through the area covered with 5G network in a short period of time, the terminals will perform unnecessary switching procedures twice, resulting in waste of signaling and power. After analyzing the signaling flow in the non-access layer of the mobile terminal protocol stack, the method of delayed handover is proposed to reduce the times of unnecessary switches, where the terminals have to wait for a period of time before switching to the 5G network. As can be seen from the modeling and simulation part, the method of delayed handover can guarantee the user experience as well as reducing handover times. Through analysis, this paper also shows the optimal delay time to make the benefits of the delay switching strategy greater.