Beamformer Designs for Energy-Efficient Multi-Cell Physical Layer Multicasting

In this paper, we address the problem of energy efficiency for group communications over 5G networks. We consider multicast broadcast multimedia services (MBMS) where Base Stations (BS) cooperate to convey a common information to multiple users. The problem is formulated as the global energy efficiency (GEE) maximization under power constraints. We invoke the principle of sequential convex approximation to tackle the original non-convex problem by providing a conservative approximation. Closed-form solutions are derived and a centralized scheme is designed to find stationary solutions to the original non-convex problem. A distributed implementation with limited communication overhead among the BSs is then proposed. These theoretical findings are further validated through numerical results.