Joint beamforming, resource allocation, and scheduling for multi-cell multi-user MIMO-OFDMA systems

Abstract

In this paper, we formulate an optimization problem for joint transmit beamforming, resource allocation, and user scheduling for multi-cell multi-user multiple-input multiple-output (MIMO) orthogonal frequency division multiple access (OFDMA) networks aiming at total average weighted system throughput maximization. Despite the non-convex and combinatorial characteristics of the resulting problem, we transform it into a standard convex optimization problem by introducing an extra sum interference constraint and certain relaxations, which leads to a lower bound for the original problem. Applying Lagrange dual decomposition, we successfully solve the transformed problem in a distributed manner with closed-form expressions for the optimal beamformers, power adaptation, and subcarrier allocation. Numerical results show that our proposed scheme provides a considerable performance gain compared to other existing strategies in terms of weighted system throughput.