A Novel Cognitive Scheme based on Dual-threshold Energy Detection in Satellite Systems

Abstract

With the development of Spatial Information Network (SIN), the number of satellites in space continuously increases. However, the available spectrum resources are scarce. To address the spectrum scarcity, sharing the spectrum between different communication systems is a promising option. In this paper, a novel cognitive satellite scheme with geostationary earth orbit (GEO) and low earth orbit (LEO) broadband systems is studied. First, we present the concept of Cognitive Satellite Positioning (CSP) to describe the LEO satellite motion relative to the ground. Then, due to the uncertainty of space noises and absence of priori knowledge, an optimization algorithm with dual-threshold energy detection becomes a preferred candidate for satellite system, and a soft/hard fusion strategy is adopted so as to achieve a good balance between the traffic load of the dedicated links and the accuracy of Spectrum Sensing(SS). Finally, in conjunction with Radio Environment Mapping (REM) to improve the spatial reliability of SS. Numerical results show that the spectrum recognition scheme similar to the detection performance of cooperative SS only using soft fusion, which has strong robustness under environment with high uncertainty. The work here provides theoretical basis and technical support for the spectrum sharing strategy between GEO and LEO satellite system.