Constrained weighted sum rate maximization for multicast service in downlink OFDMA

Abstract

In this paper, we study the weighted sum rate (WSR) maximization methods for the multicast service in the downlink orthogonal frequency division multiple access (OFDMA) system. Based on Lagrange dual composition, we design several WSR maximization algorithms under both sum transmit power and per-subchannel transmit power constraints. Compared to available results for multicast resource allocation which were suboptimal or involved a large complexity, our methods are asymptotically optimal, stable, and have a low complexity. Three algorithms are developed, a duality method with only sum transmit power constraint, and two duality methods considering both sum transmit power and per-subchanneltrans-mit power constraints. Simulation results show that the proposed method converges very fast and always meets the power constraint strictly. Furthermore, in the case of the per-subchannel transmit power constraint, the improved duality scheme can bring significant performance gain than the conventional duality scheme. © 2012 ACM.