We propose a low-power mobile low earth orbit (LEO) satellite communication architecture, employing double reconfigurable intelligent surfaces (RIS) to enhance energy efficiency and signal performance. With a distance between RISs that satisfies the far-field requirement, this architecture positions one small RIS each in the near-field of the satellite's antenna and the user on the ground. Moreover, we develop a path loss model for the double-RIS communication link, considering the near-field and far-field effects. Further, with the help of dual-stage beamforming, the proposed system maximizes the signal power and minimizes power consumption. Simulation results show that the proposed architecture can reduce the power consumption with 40 dB in the uplink, with a small $0.25^2$ $\text{m}^2$ RIS near the user, to communicate in energy-constrained LEO satellite communication circumstances.

翻译：本文提出了一种低功耗移动低地球轨道（LEO）卫星通信架构，采用双可重构智能表面（RIS）以提升能量效率和信号性能。该架构在满足远场条件的RIS间距下，将两个小型RIS分别部署于卫星天线和地面用户的近场区域。此外，我们建立了考虑近场与远场效应的双RIS通信链路路径损耗模型。通过双级波束成形技术，所提系统能够最大化信号功率并最小化功耗。仿真结果表明：在能量受限的LEO卫星通信场景中，采用靠近用户的0.25² m²小型RIS时，该架构可使上行链路功耗降低40 dB。