FIRST-ORDER FAST ALGORITHM FOR STRUCTURALLY OPTIMAL MULTI-GROUP MULTICAST BEAMFORMING IN LARGE-SCALE SYSTEMS

We consider multi-group multicast beamforming in large-scale systems to minimize the transmit power subject to the signal-to-interference-plus-noise ratio (SINR) requirements. Based on the optimal multicast beamforming structure, we propose a fast first-order algorithm to obtain the beamforming solution. The algorithm utilizes the successive convex approximation (SCA) method and solves each SCA subproblem by dual reformulation along with the extragradient method for fast closed-form updates. Initialization methods are also explored, including an extragradient-based fast initialization approach that is proposed to generate initial feasible points for SCA. Simulations show that the proposed algorithm provides a near-optimal performance with substantially lower computational complexity for large-scale systems than the existing algorithm.