Intelligent reflecting surface‐assisted downlink nonorthogonal multiple access systems

Abstract

Summary 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.

An efficient algorithm for resource optimization in IRS-mmWave-NOMA B5G wireless networks

“…Although mmWave and NOMA technologies greatly enhance system performance, there are also certain disadvantages. MmWave signals often experience significant route loss and are easily obstructed by objects [ 23 , 24 ]. The application potential of millimeter-wave NOMA technology will be reduced due to interference between strong and weak NOMA users [ 25 , 26 ].…”

Multiple reconfigurable intelligent surfaces assisted downlink NOMA system

“…Reconfigurable intelligent surfaces (RISs) have emerged as a critical enabling technology for sixth‐generation (6G) networks to improve network coverage and spectrum and energy efficiencies (SEEs) 1 . RIS panels are equipped with many low‐cost passive elements, which reconfigure propagation environments by adjusting the phase of reflecting elements 2,3 . Therefore, it enhances the received signal‐to‐noise ratio (SNR) of users.…”

“…1 RIS panels are equipped with many low-cost passive elements, which reconfigure propagation environments by adjusting the phase of reflecting elements. 2,3 Therefore, it enhances the received signal-to-noise ratio (SNR) of users. Non-orthogonal multiple access (NOMA) is a promising technology that connects many users in a network, thereby offering low latency, massive connectivity, and more reliability.…”