NOMA-Oriented Spectrum Sensing for LEO Satellite-Terrestrial Downlink Communications

The collaboration of terrestrial infrastructure and satellites has become one of the main features of 6th-Generation (6G) mobile communication networks. While promoting the integration of these architectures with different dimensions, the scarcity of spectrum resources becomes a key factor restricting further development. Confronted with such a significant challenge, it is imperative to develop effective strategies aimed at comprehensively enhancing the efficiency of spectrum utilization. This letter introduces a Non-Orthogonal Multiple Access (NOMA)-oriented spectrum sensing technique, which serves downlink scenarios of multi-satellite in terrestrial-satellite communications. We propose the corresponding operational principles and deduce the sensing threshold in different mobile coverage scenarios of Low Earth Orbit (LEO) satellites. Simulation results manifest that compared with the Orthogonal Multiple Access (OMA) system, the proposed technique achieves a maximum 18.6% throughput gain under the given conditions.