Joint Frequency Grouping and Noma-Based Spectrum Sharing Scheme for Low Earth Orbit Satellite-Terrestrial Integrated Networks

With the rapid evolution of satellite-terrestrial integrated networks (STIN), spectrum sharing has been proposed as a promising technique to enhance the utilization efficiency of limited frequency resources. However, frequency reuse inevitably introduces Co-channel Interference (CCI), which can significantly degrade the performance of integrated satellite-terrestrial systems, particularly in low Earth orbit (LEO) satellite-terrestrial networks. To address this challenge, we propose a novel spectrum sharing scheme that jointly optimizes frequency grouping and non-orthogonal multiple access (NOMA) techniques for LEO-integrated networks. Furthermore, the Tabu Search algorithm is employed to address the combinatorial optimization problem inherent in resource grouping. The simulation results demonstrate that this scheme improves the throughput of satellite users and takes into account the spectrum efficiency of terrestrial base stations, thus significantly improving the overall utility of the integrated network.