Cooperative Spectrum Sharing in a Co-existing LEO-GEO Satellite System

Low Earth Orbit (LEO) satellites are becoming increasingly important among the existing satellite communication systems. Due to its low orbital profile, the LEO satellites can provide high-speed, low-latency, and ubiquitous services for ground users. However, as the number of satellites continues to increase, frequency bands as non-renewable resources will seriously restrict the future evolution of the LEO networks. In this paper, a flexible spectrum sharing and cooperative service method is proposed to address the collinear interference issue caused by LEO satellites while passing through the coverage area of the GEO beam. By using the continuous power allocation optimization, our scheme ensures that the service of the LEO satellites will not lead to the degradation of the service quality of the GEO beam. Meanwhile, by taking full advantage of the cooperation between LEO satellites, the quality of their service can be significantly improved. Simulation results show that our proposed algorithm converges quickly. The transmission efficiency and the stability of the system can all be guaranteed.