Efficient Data Download for LEO Satellite Networks Based on Inter-satellite Offloading

The high dynamism and limited-energy of low-earth-orbit (LEO) satellite make it difficult to download massive data to Ground stations (GSs) within limited and rapidly varying contact time. To address this challenge, this paper proposes an efficient data download scheme for LEO satellite networks based on inter-satellite offloading, which optimizes the long-term trade-off between energy consumption and data downloads under on-board power and backlog stability constraints. Specifically, the long-term stochastic optimization problem of data downloading is transformed into multiple deterministic single-time slot problems through Lyapunov optimization theory. Furthermore, a distributed solving strategy is developed to enable each satellite to independently determine the transmit power allocation and data processing decisions in closed-form with low computational complexity. Finally, simulation results demonstrate the superiority of the proposed scheme over benchmarks, e.g., achieving asymptotically optimal trade-off between energy consumption and data downloads, while maintaining stability of the on-board backlog.