Joint Beamforming and the Artificial Noise Security Scheme Based on Successive Convex Approximation in Multi-relay Cognitive Network

Abstract

Abstract. To solve the transmission problemof physical layer security(PLS) in relay cognitive radio network (CRN), this paper investigates the PLS transmission scheme of multiple relays CRN, which contains two pairs of secondary nodes without direct link each other. Compared with the model that consists ofa pair of secondary node users and a single relay in terms of theoretical analysis and optimization, the proposed scheme is more complicated. To maximizethe joint secret rate of the secondary users,power allocation of the twosecondarysource transmission node withbeamforming andartificial noise assist (PBNAS) is obtained. Furthermore, exploiting the semidefinite programming theory (SDR) and the successive convex approximation (SCA) method, the original complex nonconvex problem is transformed into a convex optimization problem, and the iterative procedure is summarized.Finally, the security transmission rate versus different number relays andrelays total power is simulated. The simulation results show that the security performance of the PBNAS scheme is the best.