Ergodic Sum-Rate Maximization for Multi-LEO Satellite Cooperative Beamforming Systems

We investigate a downlink communication system with multiple low Earth orbit (LEO) satellites, where inter-satellite links (ISLs) enable cooperative transmission. To address the difficulty of acquiring instantaneous channel state information (CSI), we exploit statistical CSI and formulate a precoding optimization problem to maximize the ergodic sumrate. To overcome the complexity of ergodic rate computation, we approximate the ergodic rates and propose a weighted minimum mean squared error-based algorithm. Numerical results demonstrate that the proposed method achieves performance close to a benchmark scheme based on perfect CSI and significantly outperforms non-cooperative transmission.