Optimal spectrum sensing in cooperative cognitive two-way relay networks

This paper investigates a network consisting of some CR terminals distributed between two primary transceivers. In the proposed network model, CR nodes assist the primary transmission as a two-way amplify-and-forward relaying scheme when the primary transceivers are in operation. By using distributed beamforming techniques among CR nodes, we propose an optimal solution to maximize the performance of spectrum sensing in terms of signal-to-noise ratio (SNR) at the CBS while satisfying the quality of service requirements of primary receivers. We demonstrate the superiority of sensing performance in the proposed method by relaxing the problem into the semidefinite form and we achieve the maximum value of SNR in the CBS by using an iterative algorithm.