【摘要】 卫星通信能够提供超视距、大容量的通信服务，但在城市区域、峡谷森林等视线受遮蔽严重的区域，会出现视距衰落严重、多径效应显著等问题，影响通信质量。近年来出现的智能超表面(RIS)可以通过动态控制反射单元的电磁性质，构建可控电磁环境，为改善低轨(LEO)卫星通信质量提供新的思路。本文基于RIS基本原理与优势，对RIS用于LEO卫星通信中信道建模、信道估计、波束成形等关键技术进行探讨，最后分析了目前RIS在实际应用中面临的主要挑战，以期为LEO卫星场景下的RIS研究提供参考。更多还原

【Abstract】 Satellite communication can provide over-the-horizon, large-capacity communication services. Nevertheless, there will be serious line-of-sight fading and significant multipath effect in urban areas, canyons, forests and other areas where the line of sight is seriously obscured, which will result in the degradation of network communication performance. Recently, an emerging technology―the Reconfigurable Intelligence Surface(RIS) is capable of dynamically altering wireless channels by flexibly controlling the electromagnetic properties of passive reflecting elements, providing a novel route for improving the quality of Low Earth Orbit(LEO) satellite communication. Based on the basic principles and advantages of RIS, the key technologies such as channel modeling, channel estimation, and beamforming in the RIS aided LEO satellite communication are discussed. Finally, the main challenges faced of RIS in practical applications are analyzed. This work can provide a reference for research in the field of RIS aided LEO satellite communication.更多还原