Energy-efficient coordinated beamforming for multi-cell multicast networks under statistical CSI

In this paper, we investigate the problem of energy-efficiency for physical layer multicasting in multi-cell network under the assumption that only downlink channel distribution information (CDI) is available at the base station. Each BS, equipped with multiple antennas, uses a single beamformer to convey a common information to a group of single antenna users. The problem is formulated as the global energy-efficiency maximization under each active user' outage constraints. To circumvent the high computational complexity incurred by investigating the NP-hard problem, we leverage the concept of successive convex approximation to tackle the original non-convex problem. We provide an analytical solution for the beamformer design that allows solving the original centralized problem in a distributed manner with limited signaling exchanges. Furthermore, extensive simulation analyses are provided to corroborate the validity of the theoretical findings and demonstrate the efficiency of our proposed algorithm.