Modelling and Compensation of SIC Imperfection in IRS-NOMA based 5G-System

Abstract

This article considers the impairments in the application of successive interference cancellation (SIC) at the detection phase of non-orthogonal multiple access (NOMA) users. A practical approach is proposed to model the SIC impairment which takes into account the number of multiplexed users in NOMA’s power domain, in addition to the overall number of shared radio resources. In such case the imperfection of the SIC varies in accordance with the number of users. This strategy is closer to the situation in practice than the case where the SIC is modeled with fixed error factor as in the previous research articles that already considered the matter. A channel estimation approach is also proposed, which depends on the user’s channel gain variations to predict the change in its peers’ channel so as to compensate for the error resulting from SIC imperfection. The outcome of the proposed compensation strategy is promising as the simulation results reflect significant improvement in the achievable rate and energy efficiency.