Cognitive Non-Orthogonal Multiple Access with Cooperative Relaying: A New Wireless Frontier for 5G Spectrum Sharing

TL;DR

This paper explores the integration of NOMA and cognitive radio technologies into cognitive NOMA networks to enhance spectrum sharing in 5G, proposing architectures and cooperative relaying strategies to improve performance.

Contribution

It introduces three cognitive NOMA architectures and proposes cooperative relaying strategies to mitigate interference and improve network performance.

Findings

Cooperative relaying significantly reduces outage probabilities.

Three cognitive NOMA architectures are proposed for 5G spectrum sharing.

The system aligns with 5G requirements like high efficiency and massive connectivity.

Abstract

Two emerging technologies towards 5G wireless networks, namely non-orthogonal multiple access (NOMA) and cognitive radio (CR), will provide more efficient utilization of wireless spectrum in the future. In this article, we investigate the integration of NOMA with CR into a holistic system, namely cognitive NOMA network, for more intelligent spectrum sharing. Design principles of cognitive NOMA networks are perfectly aligned to functionality requirements of 5G wireless networks, such as high spectrum efficiency, massive connectivity, low latency, and better fairness. Three different cognitive NOMA architectures are presented, including underlay NOMA networks, overlay NOMA networks, and CR-inspired NOMA networks. To address inter- and intra-network interference which largely degrade the performance of cognitive NOMA networks, cooperative relaying strategies are proposed. For each cognitive NOMA architecture, our proposed cooperative relaying strategy shows its potential to significantly lower outage probabilities. Furthermore, we discuss open challenges and future research directions on implementation of cognitive NOMA networks.