Energy Efficient Coordinated Beamforming Design in Multi-Cell Multicast Networks

In this letter, we study energy efficient physical layer multicasting in multi-cell networks where each base station is equipped with multiple antennas, and transmits a common message using a single beamformer to multiple users in the same cell. The goal of our coordinated beamforming design is to maximize the worst case system energy efficiency while guaranteeing that received signal-to-interference-plus-noise ratio (SINR) at each user is above a predetermined threshold. The considered optimization problem is in a non-convex fractional form and hard to tackle. We propose to first transform the original problem into a tractable optimization problem which is then solved by developing an iterative optimization algorithm with provable convergence. Numerical results further validate the effectiveness of our proposed algorithm and show that the developed algorithm converges to a stable point in a limited number of iterations.