Performance analysis of Spectrum Sensing based on Distributed Satellite Clusters

This paper investigates the spectrum sensing performance of a distributed satellite clusters (DSC), where the sensing signals received by each cooperative satellite can be fused at the signal-level to enhance the sensing ability of weak signals. In particular, by assuming that the satellite-relay link undergoes shadowed-Rician (SR) fading, we first derive a closed-form expression for correct detection probability $(P_{d})$ of the considered system with maximum ratio combining (MRC). However, when the channel state information can not meet the requirements, equal gain combining (EGC) provides an alternative to slightly reduce the complexity. Therefore, we provide another closed-form expression of $P_{d}$ based on EGC, using the specially derived probability density function of the sum of SR random variables with independently identical distribution. Simulation results are provided to validate our theoretical analysis and to show that the proposed scheme can achieve the best spectrum-sensing performance, comparing with the traditional energy detection, eigenvalue ratio test and the generalized likelihood ratio test.