An Edge-assisted Solution for Reliable Service Continuity in LEO-based Non-Terrestrial Networks

Non-Terrestrial Networks (NTNs) will be of great importance in offloading terrestrial networks, as they will be able to provide services to users deployed anywhere at any time. Specifically, Low-Earth Orbit (LEO) satellite constellations enable global seamless connectivity and service delivery with low latency. Nevertheless, the rapid rotation of LEO satellites around the Earth results in frequent interruptions of the feeder link between a LEO satellite and an NTN Gateway (GW) located on the Earth's surface, thereby triggering the procedure of feeder link switch over (FLSO). The Third Generation Partnership Project has defined two modalities of FLSO. The soft mode entails the simultaneous activation of two feeder links between one satellite and two different NTN-GWs. Differently, only one feeder link is enabled at a time in the hard mode. In the literature, the exploitation of Inter-Satellite Links (ISLs) between LEO satellites has been considered to reduce the required FLSO time when the NTN-GWs are positioned far from each other. In this paper, we propose an edge-assisted algorithm for the dynamic selection of the ISL-based FLSO procedure, which considers the reliability of ISLs to ensure that LEO satellites cooperate in a trustworthy manner, thereby improving service continuity. The performance of the proposed solution is compared to the existing solution, which does not consider the trustworthiness of the ISLs, in terms of the time required for the FLSO.