DDPG-QoSRA: A Cross-Layer QoS-Optimized Routing Algorithm for Large-Scale LEO Satellite Networks

With the expanding constellation scale and growing demands for Quality of Service (QoS) assurance, satellite networks are evolving toward multi-layer architectures. Traditional single-layer designs fail to ensure link stability and service continuity for emerging applications. This paper proposes a cross-layer communication design for large-scale Low Earth Orbit (LEO) satellite networks oriented toward QoS optimization. Specifically, we establish a dynamic topology model for large-scale LEO satellite networks and define the multitask scenario. The routing problem is formulated as an Integer Linear Program (ILP) to maximum the average link utilization ratio under unsplittable flow constraints. We propose the Deep Deterministic Policy Gradient-Based QoS Routing Algorithm (DDPG-QoSRA) to ensure both path reliability and the transmission performance of critical services. Finally, the simulations show the effectiveness and superiority of the proposed algorithm.