Performance analysis of downlink NOMA over η–µ and κ–µ fading channels

Abstract

Non-orthogonal multiple access (NOMA) is recognised as an improved multiple access technique as compared with OMA technique to fulfil the requirements of fifth-generation wireless communication systems. In this study, the outage probability and sum-rate analysis of downlink multi-user NOMA system over the generalised fading channels, i.e. η–µ and κ–µ, are presented. Specifically, the outage probability of NOMA is analysed with fixed target rate and OMA rate. The mathematical expressions for the outage probability and sum rate with a fixed set of power allocation coefficients are derived and verified through the simulation results. The impact of system parameters such as number of users, power allocation coefficients, fading parameters etc. on the performance of NOMA system is investigated. NOMA with given fixed target rate offers better outage performance as compared with OMA. However, NOMA with OMA rate offers better outage performance for the near user only. The sum rate and near user rate of NOMA improves with signal-to-noise ratio; however, the far user rate does not follow the same trend.