Energy-Efficient RIS-Assisted Satellites for IoT Networks

The use of satellites to provide ubiquitous coverage and connectivity for densely deployed Internet of Things (IoT) networks is expected to be a reality in emerging 6G networks. Yet the low battery capacity of IoT nodes constitutes a problem for their direct connectivity to satellites, which are located at altitudes of up to 2000 km. In this paper, we propose a novel architecture involving the use of reconfigurable intelligent surface (RIS) units to mitigate the path loss associated with long transmission distances. These RIS units can be placed on satellite reflectarrays, and, when used in broadcasting and beamforming, they can provide significant gains in signal transmission. This study shows that RIS-assisted satellites can provide up to 10^5 times higher downlink and achievable uplink rates for IoT networks.