Adaptive Resource Allocation for Improved DF Aided Downlink Multi-User OFDM Systems
In this paper, the authors propose a joint resource allocation algorithm for an OFDM-based multi-user system assisted by an improved Decode-and-Forward (DF) relay. They aim at maximizing the sum rate of the system by jointly optimizing subcarrier pairing, subcarrier pair-user assignment, and power allocation in such a single DF relay system. When the relay does not perform any transmission on some subcarriers in the second phase, they further allow the source to transmit new symbols on these inactive subcarriers. They effectively solve the formulated mixed integer programming problem by using continuous relaxation and dual minimization methods.