Resource Allocation for Secure Multicarrier AF Relay System Under Total Power Constraint

In this letter, we consider an amplify-and-forward-relay-aided secure multicarrier communication between two nodes with an eavesdropper. We solve the sum secrecy rate maximization problem by solving the following two problems: 1) subcarrier usage policy at the source and the relay; and 2) power allocation among subcarriers between the source and the relay under a total system power constraint. We provide a suboptimal closed-form solution to the problem that involves mixed-integer variables and a nonlinear fractional function. The numerical results demonstrate an improved sum rate by the proposed scheme over a scenario without relay.