Joint User Association, Power Allocation and Beamforming for NOMA-Based Integrated Satellite-Terrestrial Networks.

This paper investigated a non-orthogonal multiple access (NOMA)-based integrated satellite-terrestrial network (ISTN), where each user can select to access a terrestrial base station (BS) or the satellite according to the capacity of BS and their individual transmission requirements. A two-stage algorithm is proposed to solve the achievable sum rate maximizing resource optimization problem. In the first stage, user associations are determined based on individual preference lists and the backhaul capacities of the access points (APs).