Intelligent Reflecting Surface Aided Multiple Access Over Fading Channels

This paper considers a two-user downlink transmission in intelligent reflecting surface (IRS) aided network over fading channels. Particularly, non-orthogonal multiple access (NOMA) and two orthogonal (OMA) schemes, namely, time division (TDMA) frequency (FDMA), are studied. The objective is to maximize the system average sum rate for delay-tolerant transmission. We propose adjustment dynamic phase one-time adjustment. power budget, minimum data rate, discrete unit modulus reflection coefficient considered as constrains. To solve problem, shifters algorithms with low complexity proposed obtain near optimal solutions. With given satisfaction of time-sharing condition, resource allocations obtained using Lagrangian dual decomposition. numerical results reveal that: i) NOMA by IRS outperforms conventional channels; ii) continuous block, TDMA scheme performs better than FDMA scheme; iii) increasing user requirement has less impact on IRS-NOMA IRS-OMA system.