Resource allocation for IRS‐assisted MC MISO‐NOMA system

Abstract

Abstract In this paper, a downlink multi‐user communication of an intelligent reflecting surface (IRS)‐assisted multiple‐input single‐output (MISO) power‐domain non‐orthogonal multiple access (NOMA) system is investigated. Considering multi‐carrier (MC) transmission and to enhance user fairness, two users are assigned to the same subcarrier. For such a system, the authors optimize active beamforming at the base station (BS), subcarrier allocation policy, and phase shifts at the IRS to maximize the system throughput. A semi‐definite relaxation (SDR) is applied to tackle the non‐convex optimization problem, and an alternating optimization (AO) algorithm is proposed to obtain a suboptimal solution. Numerical results illustrate the higher throughput of the proposed MC multi‐user IRS‐aided MISO‐NOMA system as compared to the conventional IRS‐assisted orthogonal multiple access (OMA) system.