量子卫星通信能够解决量子移动通信在航海、航空领域中对于远距离和大范围的需求, 而星上交换是量子卫星通信的关键技术之一.本文以低轨道量子卫星通信星上交换为研究对象, 提出了一种新的星上交换算法——终端测距法.利用该算法测得终端到相邻小区中心的距离, 并将测得的数据上传给当前服务卫星系统, 再由卫星系统通过比较距离大小决定终端是否切换.数学分析和仿真结果表明, 该算法可靠性高、操作方便, 能够在各卫星之间实现平稳切换.

Quantum satellite communication can meet the requirement of quantum mobile communication among sailing, aviation field with longdistance and extensiveness communications, and onboard switching is one of the key techniques in quantum satellite communication. Based on the onboard switching technique in low earth orbit (LEO) quantum satellite communication, a novel algorithm is proposed that is terminal measuredistance method. By using this algorithm, the distances between terminals and its adjacent cell center are measured, and then the distances data are uploaded to the current satellite system, finnaly the satellite system compares the distances and determines whether to handover or not. Mathematical analysis and simulation results show that the proposed algorithm has high reliability, is easy to operate, and can smoothly switch between the different satellites.