Adaptive User Pairing for Downlink NOMA System with Imperfect SIC

TL;DR

This paper introduces an adaptive user pairing algorithm for downlink NOMA systems with imperfect SIC, demonstrating improved performance over existing methods and highlighting conditions where NOMA may not outperform OMA.

Contribution

The paper proposes a novel adaptive user pairing algorithm for downlink NOMA with imperfect SIC, improving performance over existing algorithms and analyzing when NOMA surpasses OMA.

Findings

NOMA with imperfect SIC does not always outperform OMA.

The proposed A-UP algorithm outperforms state-of-the-art pairing algorithms.

Bounds on channel coefficients and power allocation improve NOMA performance.

Abstract

Non-orthogonal multiple access (NOMA) has been recognized as a key driving technology for the fifth generation (5G) and beyond 5G cellular networks. For a practical dowlink NOMA system with imperfect successive interference cancellation (SIC), we derive bounds on channel coefficients and power allocation factors between NOMA users to achieve higher rates than an equivalent orthogonal multiple access (OMA) system. We propose an adaptive user pairing (A-UP) algorithm for NOMA systems. Through extensive simulations, we show that NOMA with imperfect SIC is not always superior to OMA. Further, the proposed A-UP algorithm results in better performance than state-of-the-art NOMA pairing algorithms in presence of SIC imperfections.