Joint Power Allocation for OFDM-Based Non-Concurrent Two-Way AF Relaying

We consider an amplify-and-forward non-con-current two-way relaying for an orthogonal frequency division multiplexing (OFDM) system, where the base station (BS) serves a transmit-only user (TU) and a receive-only (RU) user, whose receive signal is interfered by the TU transmit signal. We design an overhearing-based interference cancellation scheme wherein the RU collects side-information by overhearing the TU transmit signal, and uses that to cancel its interference. We then jointly allocate power at the TU, BS, and the relay nodes across OFDM subbands to optimize the sum-rate, which is a non-convex problem. We solve it using successive convex approximation (SCA), which approximates the non-convex sum-rate optimization as a sequence of convex programs. The SCA approach is shown to converge within few iterations. Numerical results demonstrate the improved performance of the proposed algorithm over other state-of-the-art algorithms.