Optimal power allocation for secure multi-carrier relay systems

Abstract

We study the multi-carrier decode-and-forward relay communication system, where an eavesdropper exists. The source power and relay power are optimized over all subcarriers to maximize the sum secrecy rate under a total system power constraint. From the power allocation result, an optimal transmission strategy is determined among no transmission, direct transmission, and relay transmission on each subcarrier. In numerical results, the performance of the optimal power allocation is evaluated and compared for various scenarios.