Spectrum sensing based on angular reciprocity in cognitive satellite communication system

Satellite communication is attracting increasing attention owing to its freedom from geographical constraints. However, its spectrum resources are limited, and it is susceptible to interferences. Therefore, cognitive radio technology can be used to detect and prevent interferences as well as improve spectrum utilization. To improve the spectrum sensing performance, an angle reciprocity-based spectrum sensing (ARSS) scheme is proposed in this study. The scheme exploits the reciprocity between the known beam’s central angle and the unknown signal’s arrival angle, with the reciprocity controlled by the narrow characteristic of the satellite’s beam owing to long-distance propagation. In this scheme, we use the beam’s central angle instead of the signal’s actual angle to process the received signal, and then the processed data are used as the sensing statistics for spectrum sensing. The simulation results show that the proposed ARSS scheme exhibits better satellite spectral sensing performance compared with the energy detector (ED).