Performance analysis of NOMA systems over Rayleigh fading channels with successive‐interference cancellation

Abstract

In this study, non-orthogonal multiple access (NOMA) is considered for multiusers wireless communications over Rayleigh fading channel. The base station (BS) utilises NOMA technique to secure connectivity, users fairness and high spectral efficiency for multiusers with different channel conditions. Moreover, a power allocation mechanism is applied at the BS by giving each user its required power allocation factor (PAF) in order to share the available power. Therefore, this technique allows the users of interest to communicate with the BS over the same frequency band simultaneously in the power domain. Moreover, successive interference cancellation is applied for users with the lower PAF to remove the strong signal of the other users. Furthermore, exact expressions are derived for different performance metrics, and the probability density function of the signal-to-interference-plus-noise ratio is derived at each terminal and then exploited to obtain the outage probability and the probability of error. The performance analysis is verified via Monte-Carlo simulations demonstrating closed-match with theoretical analysis.