Double-RIS Assisted Cooperative Spectrum Sensing for Cognitive Radio Networks

This letter investigates a double-reconfigurable intelligent surface (RIS) assisted cooperative spectrum sensing (CSS) system. We formulate the phase shift optimization problems of the two RISs to maximize the cooperative sensing performance for two CSS schemes, namely, data fusion and decision fusion. Based on the alternating optimization technique, we show that these intractable non-convex problems can be successfully tackled by jointly using the successive convex approximation and penalty convex–concave procedure methods. Simulation results demonstrate that the double-RIS assisted CSS system with the proposed phase shifts optimization algorithm achieves significant detection performance improvement compared to other baselines.