A Lyapunov Optimization Framework for Green Satellite Communications

Renewable-powered multibeam satellite systems are increasingly expected to support edge-like service provisioning in remote and infrastructure-limited environments. In such systems, the satellite payload buffers stochastic service requests, accounts for onboard processing constraints, and delivers queued workloads through adaptive multibeam downlink transmission subject to renewable-energy availability. The coexistence of fast-varying wireless channels, stochastic service queues, and slowly evolving energy supply creates a cross-timescale online control challenge. This paper develops a Lyapunov-based online control framework for queue-aware and energy-adaptive multibeam satellite service provisioning. An energy-deficit virtual queue is incorporated into the Lyapunov drift-plus-penalty procedure to track the accumulated gap between payload energy consumption and harvested renewable energy, enabling transmission decisions to respond to both service backlog and long-term energy availability. The resulting policy is implemented through LONE, a low-dimensional scalar-search algorithm with SDR-based beamforming evaluation. Theoretical analysis establishes service-queue stability, energy-deficit virtual-queue stability, and the corresponding delay–energy tradeoff. Simulations show that LONE provides tunable delay–energy performance under stochastic traffic, time-varying channels, and renewable-energy dynamics.