IRS-NOMA Transmission in Cooperative Networks

In this letter, we propose a novel scheme that utilizes a hybrid relay and intelligent reconfigurable surface (IRS) to enable simultaneous transmission of two symbols from a source to a destination using a non-orthogonal multiple access (NOMA) scheme. As the proposed scheme benefits from the advantages of the multiplexing technique, the spectral efficiency increases. In the devised scheme, the achievable sum-rate is maximized by optimizing the IRS coefficients and the NOMA power allocation coefficients. We derive closed-form expressions for these optimal coefficients based on the channel state information. Simulation results demonstrate the superiority of the proposed scheme compared to benchmark scenarios.