Resource Allocation Design for IRS-Aided Downlink MU-MISO RSMA Systems

Abstract

In this paper, we consider the max-min fairness (MMF) transmission for an intelligent reflecting surface (IRS)- aided multi-user multiple-input single-output (MU-MISO) rate splitting multiple access (RSMA) downlink system. Our resource allocation design aims to maximize the minimum transmission rate among multiple single-antenna users via optimizing the transmit beamformers at the transmitter and the reflecting phase shift vector at the IRS. To this end, the algorithm design is formulated as a mixed non-convex and combinatorial optimization problem which takes into account the discrete phase shift and the maximum transmit power budget. To address the intractability of the design optimization problem, the successive convex approximation (SCA) technique, the penalty method, and the alternating optimization (AO) approach are exploited to design a suboptimal iterative algorithm for obtaining an effective solution of the considered problem. Simulation results demonstrate the MMF rate performance gains obtained by the proposed IRS-aided RSMA system compared with several baseline schemes.