IRS‐enabled NOMA in energy scavenging underlay networks: Performance analysis

Summary By transmitting concurrently signals of different users, non‐orthogonal multiple access (NOMA) meliorates spectral efficiency. Moreover, intelligent reflective surface (IRS) is introduced as a bridge between a NOMA transmitter and a distant NOMA receiver. This role enhances spectral efficiency and communication reliability. Furthermore, energy scavenging underlay networks (ESUNs) enable unlicensed transmitters to operate using scavenged energy on licensed spectrum allotted to licensed transmitters, enhancing both spectral and energy efficiencies. Although IRS‐assisted NOMA further meliorates spectral efficiency and communication reliability for traditional ESUNs, it faces challenges like fading severity and nonlinear energy scavenging (nlES), which directly impact scavenged energy and communication reliability. Thence, the paper assesses three pivotal performance metrics—energy efficiency, outage probability, and throughput—for IRS‐assisted NOMA in ESUNs, shortly RaNOehU, considering realistic factors such as relatively‐general Nakagami‐ m fading and nlES. Demonstrative results reveal that the quantity of reflective elements, fading severity, and nlES dramatically influence the performance of RaNOehU. Notably, appropriate selection of power/time division parameters and desired data rate can hinder complete outage and attain optimum performance. In addition, the proposed IRS‐assisted NOMA is shown to outperform its reference, which is IRS‐assisted orthogonal multiple access, emphasizing the advantages of NOMA.