End-to-End Scheduling of Space-Air-Ground Integrated Networks for High-Speed Railways

Space-air-ground integrated networks (SAGINs) offer seamless coverage and have emerged as a promising solution for high-speed railway (HSR) communications, which traverse various environments. This paper investigates a SAGIN architecture wherein the low earth orbit (LEO) satellite interfaces with multiple high altitude platforms (HAPs), establishing connections with high-speed trains. Operating such a mobile network requires a coordinated design of both the radio access and backhaul networks. The flows transmitted by the trains are accessed through HAPs and routed by the LEO satellite to reach the destination trains. Our objective is to maximize the number of scheduled flows while satisfying quality of service (QoS) requirements. To address this, we propose a joint transmission scheduling scheme for access and backhaul communications, facilitating multi-hop transmissions in this scenario, thereby enhancing network performance and efficiency. Simulation results show that the proposed scheme outperforms existing schemes in meeting the flow's QoS requirements.