Impact of Satellite Mobility on the Delivery of Multimedia Services over LEO-based NTNs

The Non-Terrestrial Network (NTN) represents one of the major components in future wireless systems. Both academia and industry are interested in Low-Earth Orbit (LEO) satellites orbiting the Earth at low altitudes. Indeed, global connectivity can be achieved through constellations of LEO satellites, which also ensure network access and deliver services anytime and anywhere with low latencies. However, LEO satellite fast speeds around the Earth result in frequent feeder link breaks between the NTN platform and the NTN Gateway (NTN-GW) and, consequently, the network has to perform numerous feeder link switch-over procedures. The Third Generation Partnership Project (3GPP) distinguishes two feeder link switch-over modalities. The soft procedure foresees the establishment of two feeder links with two different NTN-GWs at the same time by releasing the old feeder link once the new one is activated. The hard procedure foresees the establishment of one feeder link per time: first, the old feeder link is released, then the new feeder link is activated, thus causing service interruptions. In this paper, through a simulation campaign conducted by means of the MATLAB tool, we evaluate the system performance in terms of data loss for the two feeder link switch-over modalities. Finally, some future research ideas are considered to tackle the issue of long service disruption above all in the case of hard feeder link switch-over.