Resource allocation for OFDM multiple-access relay channels with network coding

Joint scheduling and resource allocation in uplink orthogonal frequency division multiplexing (OFDM) systems is complicated, and even gets intractable with large subcarrier and user number. This paper investigates the resource allocation for OFDM-based multi-user multiple-access relay channels (MARC) with network coding. We formulate a joint optimization problem considering source pairing, subcarrier assignment, subcarrier pairing and power allocation to maximize the sum-rate under per-user power constraint. The problem is addressed in polynomial time by optimizing three separate subproblems, and afterwards three low-complexity suboptimal algorithms are further proposed. The simulation results demonstrate performance gain of the proposed algorithms versus per-node transmit power and source nodes number, respectively.