Dynamic MBSFN Beam Area Formation in 6G Multi-Beam Non-Terrestrial Networks

Providing innovative services and ensuring ubiquitous, ultra-high density, extreme speed, and very-low latency communications are essential for future Sixth-Generation (6G) systems, where the importance of Non-Terrestrial Networks (NTNs) will incredibly rise. However, the management of both capacity and radio spectrum remains one of the main challenges when a huge number of devices requires access to dissimilar broadcast services at the same time. To cope with these issues, traditional single-beam satellite systems have been replaced with Very-High Throughput Satellite (VHTS), where multi-beam transmissions increase the capacity, improve the spectrum utilization while limiting inter-beam interference. In this paper, we propose a Dynamic MBSFN Beam Area Formation (D-MBAF) algorithm that dynamically groups beams into dedicated MBSFN Beam Areas (MBAs) to increase the Aggregate Data Rate (ADR) of the multi-beam NTN system and deliver a given video content to all the interested NTN terminals. The D-MBAF leverages multicast subgrouping by clustering the NTN terminals into different MBAs that are simultaneously served with different data rates. Furthermore, the D-MBAF algorithmdelivers the video content in different flows: the base layer with a lower resolution and a set of enhancement layers with upper resolutions. Radio resources are efficiently allocated to avoid interference among the beams belonging to different MBAs. A simulation campaign is carried out under different scenarios to assess the effectiveness of the proposed D-MBAF algorithm w.r.t.Single-Frequency Multi-Beam Transmission scheme and multi-layer video delivery over multi-beam NTN system based on three frequency reuse schemes. Such approaches are exploited as benchmark by evaluating mean throughput, ADR, resource block utilization, and number of sent layers. Obtained results confirm that the D-MBAF algorithm outperforms the other existing schemes.