Optimal Power Allocation for Multicarrier Secure Communications in Full-Duplex Decode-and-Forward Relay Networks

For full-duplex (FD) relay networks, secure communication is an important issue. In this letter, considering decode-and-forward scheme, we investigate the optimal power allocation for multicarrier secure communication in FD relay networks. Our objective is to maximize the achievable secrecy rate of FD relay network subject to sum power constraint of the source and FD relay. The formulated nonconvex optimization problem is equivalently transformed into a convex problem. Employing Karush-Kuhn-Tucker conditions, we obtain a closed-form solution to the optimization problem. Simulation results have shown that the proposed optimal power allocation scheme for FD relaying outperforms that for conventional half-duplex relaying.