RIS-Aided LEO Satellite Communications With Two Generalized Spatial Modulation Designs

This paper presents innovative approaches to enhance LEO satellite communications by integrating reconfigurable intelligent surfaces (RIS) with generalized spatial modulation (GSM). We propose two RIS-aided LEO satellite GSM schemes (RIS-LEO-GSM and RIS-LEO-IGSM) that exploit RIS phase modulation to improve transmission efficiency with low power consumption. Both schemes significantly enhance spectral efficiency (SE) and provide flexible antenna configurations. The RIS-LEO-IGSM scheme, in particular, demonstrates superior performance by transmitting multiple constellation symbols per time slot, capitalizing on multi-antenna activation. Analytical performance of SE and average BER is also provided in this paper with some interesting insights. Simulation results confirm the BER and SE improvements of the proposed schemes, showing their potential for 6G satellite systems demanding high through put and reliability.