Rate-Splitting Multiple Access Networks Assisted by Aerial Intelligent Reflecting Surfaces

Abstract

This paper investigates rate-splitting multiple access (RSMA) networks assisted by aerial intelligent reflecting surfaces (AIRS) and assuming a downlink multiple-input single-output (MISO) scenario (AIRS-RSMA) with imperfect successive interference cancelation (SIC). An optimization problem is formulated in order to maximize the total achievable rate by optimizing the transmit beamforming and common achievable rate of the users. By using approximation and transformation techniques, we convert the optimization problem into a semi-definite program (SDP) problem. To solve this problem, an algorithm based on alternating optimization (AO) is proposed to iteratively solve the transmit beamforming problem. Simulation results are provided to demonstrate the efficiency of the proposed method, in which it is revealed that the performance gains in terms of sum-rate of AIRS-RSMA networks with robust beamforming are significantly greater than the non-optimized AIRS-RSMA and conventional non-orthogonal multiple access (NOMA) schemes.