GMR-1卫星通信系统中基于判决的切换算法

Research on handover algorithm based on handover decision in GMR-1 satellite communication system

在卫星移动通信系统中,卫星和用户都处于运动中,当用户穿越波束边界时需要进行切换。切换是卫星移动通信系统中重要的组成部分,切换算法的好坏直接影响移动通信质量。在无线资源受限的卫星移动通信系统中,不必要的切换会造成系统资源浪费。地面和卫星移动通信存在差异,地面移动通信系统中的越区切换算法在卫星移动通信网络中不再适用。针对现有波束切换算法在切换判决时没有考虑当前链路质量,提出一种基于判决的卫星波束切换算法。该算法根据当前链路质量动态地调整切换迟滞值参数的变化,并为不同速度的用户设置不同的切换触发时间。仿真结果表明,与现有的卫星点波束切换算法相比,所提算法能够合理地触发必须切换,避免不必要的切换,从而降低网络的乒乓切换和切换失败率。

In satellite communication system,handover of beam happens when the users cross the boundary of spot beam because of the high speed movement of satellite and terrestrial user. Handover is an important part of satellite mobile communication system,the performance of handover algorithm affects the service quality of users. In resource-constrained satellite mobile communication system,unnecessary handover will cause the waste of resources. There exits differences between terrestrial mobile communication system and the satellite communication system exists difference,terrestrial handover algorithm is not applicable to high-speed users on satellite mobile communication system. For the issue that existing beam handover algorithm does not take the quality of current link into account,a beam handover algorithm based on the quality of current link is proposed. In this handover algorithm,hysteresis parameter value is dynamically adjusted by the current link quality and different time to trigger is set for terrestrial users of different speeds. Simulation results show that the proposed handover algorithm can trigger the handover reasonably and avoid unnecessary handover,thereby reducing the ping-pong effect of the network and the rate of handover failure.