基于纠缠度计算的低轨道量子卫星通信切换算法

为了解决低轨道(Low Earth Orbit, LEO) 量子卫星通信的越区切换问题，提出了基于纠缠度计算的量子卫星通信切换算法。在卫星与终端距离和量子噪声的作用下，得出了环境与量子系统消相干后两粒子系统的纠缠度，并且系统始终选择与终端纠缠度最大的卫星进行切换。仿真结果表明，LEO卫星在700km和1400km轨道上在一定纠缠度下的切换成功率可达到95%以上，这很好的实现了量子卫星的平稳切换，对于构建未来全球量子通信系统及其标准的制定有着重要的技术支撑作用。

Handover Algorithm of Quantum Satellite Communication in Low Earth Orbit Based on Entanglement Degree Computing

In order to solve the problem of quantum satellite communications handover in LEO (Low Earth Orbit), the algorithm of quantum satellite communication handover in low earth orbit based on entanglement degree computing was proposed. After the influence of the distance of quantum satellite and the mobile terminal and quantum noise ,this algorithm obtained the entanglement of two subsystems when environment having the quantum decoherence in quantum systems and always choose the satellite which have the maximal entangled degree to complete real-time handover. Simulation results show that the handover success rate of this algorithm can be achieved more than 95% in both 700km and 1400km with some entanglement dgree,and it is important that can achieve smooth handover of quantum satellite. It has important supporting role in building the future global quantum communication system and its development of standards.