Fundamental Limits of Spectrum Sharing for NOMA-based Cooperative Relaying

TL;DR

This paper analyzes the fundamental limits of spectrum sharing in NOMA-based cooperative relaying systems, providing closed-form expressions for key performance metrics under interference constraints, and demonstrating NOMA's advantages over OMA.

Contribution

It offers a novel closed-form analysis of sum-rate and outage probability for NOMA-based cooperative relaying under spectrum sharing constraints.

Findings

CRS-NOMA outperforms CRS-OMA at high interference levels

Derived closed-form expressions for sum-rate and outage probability

Highlights the benefits of NOMA in spectrum sharing scenarios

Abstract

Non-orthogonal multiple access (NOMA) and spectrum sharing (SS) are two emerging multiple access technologies for efficient spectrum utilization in the fifth-generation (5G) wireless communications standard. In this paper, we present a closed-form analysis of the average achievable sum-rate and outage probability for a NOMA-based cooperative relaying system (CRS) in an underlay spectrum sharing scenario. We consider a peak interference constraint, where the interference inflicted by the secondary (unlicensed) network on the primary-user (licensed) receiver (PU-Rx) should be less than a predetermined threshold. We show that the CRS-NOMA outperforms the CRS with conventional orthogonal multiple access (OMA) for large values of peak interference power at the PU-Rx.