A Decentralized BF Scheme for Downlink NOMA Transmission in Integrated Satellite and Aerial Networks

This paper proposes a robust decentralized beam-forming (BF) scheme for downlink non-orthogonal multiple access (NOMA) transmission in an integrated satellite and aerial network (ISAN) to reduce both power consumption and signaling overhead. By employing the imperfect channel state information (CSI) and the imperfect successive interference cancellation (SIC), we formulate an optimization problem to minimize the total transmit power, subject to the rate requirements of both satellite and aerial terminals, and the transmit power budget of satellite and aerial platforms. To address this complex problem, we adopt S-procedure to transform the nonconvex constraints into convex ones and then propose a decentralized BF algorithm using Lagrange duality to obtain the satisfactory solutions in an efficient way. Finally, simulation results demonstrate that our proposed scheme can achieve a similar performance but at a lower signaling overhead as compared with the centralized BF method, and confirm the superiority of the proposed scheme in terms of power consumption over other existing works.