Resource Scheduling for High-Capacity Multicast Service in Ultra-Dense LEO Satellite Networks

Ultra-dense low earth orbit (LEO) network has been envisioned as a promising solution to improve communication coverage and reliability. In this article, we investigate the resource scheduling for the downlink multigroup multicast cooperative transmissions in an ultra-dense LEO network, where multiple LEO satellites serve as aerial base stations to cooperatively offer high-capacity multicast service for ground users (GUs) within the coverage. To obtain the system max-min fair (MMF) capacity, we formulate a weighted MMF downlink beamforming and subchannel assignment problem. As the formulated problem is NP-hard and non-convex, we adopt a many-to-many matching model to solve the subchannel assignment, and apply the successive convex approximation (SCA) coupled with Gaussian randomization and cochannel power control to obtain the downlink beamforming during the matching process. Furthermore, the matching algorithm is guaranteed to converge to a two-side exchange stable matching within finite iteration steps. Extensive numerical results are provided to demonstrate the superiority and effectiveness of the proposed resource scheduling scheme for cooperative multicast transmissions.