中文摘要：

研究了无星际链路低轨卫星移动通信系统中的馈电链路的切换问题，提出了两种馈电切换方案一最短馈电链路切换方案和最长可视时间切换方案。结合两种已有的用户链路切换准则，在构造的非均匀分布全国话务密度模型上进行了系统仿真。仿真结果表明馈电链路切换方案对系统开销影响较大，选择最长可视时间馈电链路切换方案，可以减少切换带来的信令开销，提高服务质量，具有较高的参考和实用价值。

英文摘要：

This paper discusses issues of feeder link handover and user link handover in Low Earth Orbit （LEO） satellite mobile communication systems without Inter-Satellite Links （ISL）. Two feeder link handover schemes are presented. These two schemes are simulated based on two user link handover principles and non-uniform distributed national traffic model of china. Simulation results show that the longest visible duration scheme can greatly reduce the handover frequency of gateway and improve system performance. Consequently this scheme has better value in practice.