Multi-Group Multicasting for mmWave Satellite-Terrestrial System with Rate Splitting

In this paper, we investigate the multi-group multicasting problem for satellite-terrestrial systems through transmit beamforming. In order to enhance multicasting performance, we apply the rate splitting (RS) strategy to the beamforming design. With the consideration of max-min fairness (MMF), the problem is formulated as maximizing the minimum achievable rate among all users subject to a total transmit power constraint. The problem is non-convex and difficult to solve due to the coupled rate constraints. To overcome this difficulty, we propose an efficient algorithm based on the weighted minimum-mean square error (WMMSE) and the alternating direction method of multipliers (ADMM) methods to solve the original problem by repeatedly solving a series of convex subproblems. Simulation results validate the effectiveness of the proposed algorithm.