Performance Assessment of Millimeter-Wave NOMA System With Intelligent Reflecting Surface

Abstract

This paper analyzes the performance of millimeter-wave (mmWave) non-orthogonal multiple access (NOMA) system with the aid of an intelligent reflecting surface (IRS). We derive the outage probability (OP) expressions at two users D₁ and D₂ of the IRS aided mmWave-NOMA system (the IRS-mmWave-NOMA system in the following). We validate the derived expressions via computer simulations. By considering the Nakagami- $m$ fading channels and the path loss model proposed for 5G standard in the IRS-mmWave-NOMA system, our results are more suitable in practical scenarios. Specifically, numerical results observe that even the carrier frequency is extremely high ( $f_{c}=90$ GHz) and the transmitter-receiver distances are further than 50 m, the OPs at D₁ and D₂ can achieve 10⁻⁴ when the transmit power of base station (BS) is 30 dBm (dB in the following). Moreover, the OPs at D₁ and D₂ with IRS are greatly lower than OPs without IRS. This result demonstrates the huge benefits of utilizing IRS in mmWave-NOMA system. In addition, we can use an IRS with larger number of reflecting elements to maintain the OP performance at D₁ and D₂ when the distances are increased and $f_{c}$ is higher. On the other hand, we should choose a suitable value of power allocation coefficients to obtain the same performance at D₁ and D₂.