Optimization in distributed cooperative spectrum sensing for cognitive radio

In this paper, we consider optimizing cooperative spectrum sensing in cognitive radio scenario, where two secondary users (SU) collaborate with each other via relaying scheme. Instead of directly assuming amplify-and-forward (AF) or decode-and-forward (DF) at each SU, the signal processing function is optimized via functional analysis considering both the average and the peak power constraints. We find that the optimal function acts like AF in low signal-to-noise ratio (SNR) region, while it behaves like DF in high SNR region. Furthermore, a novel estimate-and-forward (EF) processing function is proposed. Simulation results show that the proposed protocols achieve superior performance over existing protocols.