Outage and average sum‐rate analysis of intelligent reflecting surface assisted nonorthogonal multiple access system over η−μ fading channel

Summary Intelligent reflecting surface (IRS) is evolved as a one of key technology by enabling a reconfigurable, intelligent, and low power for the sixth‐generation (6G) wireless communication. In this research, an IRS‐assisted NOMA network is explored over fading channel, where IRS is placed on top of the base station (BS). IRS aids in fine‐tuning the phase of the incoming signal from BS in a meticulous way, which improves the performance of the system. The statistical channel modeling of downlink IRS‐NOMA system is proposed and validated with Monte Carlo (MC) simulation. Also, analytical expressions of OP and average sum‐rate are derived for user in IRS‐NOMA system over fading channel. Furthermore, the influence of performance factors such as number of reflecting elements (M), power allocation factor, and imperfect successive interference cancelation (I‐SIC) on OP are examined. Simulation results reveal that the IRS‐NOMA system experiences less outage compared to IRS‐OMA and conventional relaying techniques.