NOMA: An Information Theoretic Perspective

TL;DR

This paper analyzes the performance of non-orthogonal multiple access (NOMA) from an information theory perspective, demonstrating its advantages over TDMA in terms of sum and individual user rates, especially with large channel differences.

Contribution

It provides an information theoretic analysis of NOMA's capacity region and compares its performance to TDMA, highlighting scenarios where NOMA outperforms.

Findings

NOMA can outperform TDMA in sum rate.

NOMA achieves higher individual user rates.

Performance gains are significant with large channel differences.

Abstract

In this letter, the performance of non-orthogonal multiple access (NOMA) is investigated from an information theoretic perspective. The relationships among the capacity region of broadcast channels and two rate regions achieved by NOMA and time-division multiple access (TDMA) are illustrated first. Then, the performance of NOMA is evaluated by considering TDMA as the benchmark, where both the sum rate and the individual user rates are used as the criteria. In a wireless downlink scenario with user pairing, the developed analytical results show that NOMA can outperform TDMA not only for the sum rate but also for each user's individual rate, particularly when the difference between the users' channels is large.