Intelligent reflecting surface-assisted downlink nonorthogonal multiple access systems

Abstract

Recently, intelligent reflecting surface (IRS)-based communication systems are analyzed for 6G and beyond wireless networks. In this paper, we propose an IRS-assisted downlink nonorthogonal multiple access (NOMA) system by considering separate IRS for near users (NUs) and far users (FUs). The optimal power allocation strategy among NUs and FUs is formulated for the proposed downlink IRS-NOMA system. The symbol error probability and the sum-rate performance of the IRS-NOMA system are analyzed. Further, the impact of the modulation order, the number of reflecting surfaces, the number of phase shifts of reflected signals on symbol error, and power allocation between NU and FU is studied. © 2021 John Wiley & Sons Ltd.