Efficient Multipath Differential Routing and Traffic Scheduling in Ultra-Dense LEO Satellite Networks: A DRL With Stackelberg Game Approach

Low Earth orbit satellite networks (LSNs) are envisioned as key enablers of 6G by offering ubiquitous, low-latency connectivity. Their mesh topology enables multipath differential routing, which improves bandwidth utilization and reduces transmission delay. However, the growing demand for data and the dynamic, self-organizing nature of LSNs pose significant challenges for joint multipath routing and traffic scheduling under strict latency and energy constraints. To address these challenges, this paper proposes a multipath routing optimization (MRO) and traffic scheduling method tailored for multipath differential routing. Specifically, a dynamic multi-attribute graph model is developed to precisely capture the dynamic properties of LSNs. Building on this model, a MRO algorithm, integrated with a Stackelberg game framework, is introduced. The MRO algorithm employs a decomposition-based approach to identify multiple optimal paths that minimize delay and energy consumption, while the Stackelberg game framework ensures efficient traffic distribution across these paths. Numerical results demonstrate that the proposed approach significantly outperforms existing baseline methods, achieving cumulative reward improvements of 26.77% to 43.8% across four real-world network topologies and exhibiting better Pareto front coverage. Furthermore, by leveraging the rapid convergence properties of the Stackelberg game model, the proposed method enhances network throughput by 12% to 43% and reduces transmission time by 14% to 49%.