Joint Optimization of User Scheduling and Power Control in Multi-Beam NGSO Satellite Systems

In this paper, we investigate the user scheduling and power resource allocation problem for multi-beam NGSO satellite systems with uneven user demand. To effectively manage the spatial-temporal dynamics of user demands with limited power resource, we formulate an optimization problem with the objective of minimizing the system cost, which is the weighted sum of unmet system capacity and energy consumption. This problem is mixed-integer nonlinear programming and cannot be directly solved. To this end, we decompose it into two subproblems and introduce auxiliary variables to reformulate it into a tractable form. Specifically, user scheduling is initially established through a load-balancing scheme and then updated for different time slots using graph theory. Moreover, the successive convex approximation (SCA) technique is employed to achieve a near-optimal power control solution iteratively. Numerical results demonstrate that the proposed method significantly outperforms existing benchmarks, effectively reducing unmet demand and energy consumption.