A Survey on Non-Orthogonal Multiple Access for 5G Networks: Research Challenges and Future Trends

TL;DR

This survey reviews the latest research on Non-Orthogonal Multiple Access (NOMA) for 5G, highlighting its role in supporting diverse network demands and discussing future challenges and trends.

Contribution

It provides a comprehensive overview of NOMA research, innovations, and applications in 5G, and discusses future research challenges and directions.

Findings

NOMA enables serving multiple users in the same resource block.

Recent NOMA schemes can be viewed as special cases of a general framework.

Future challenges include optimizing NOMA for 5G and beyond.

Abstract

Non-orthogonal multiple access (NOMA) is an essential enabling technology for the fifth generation (5G) wireless networks to meet the heterogeneous demands on low latency, high reliability, massive connectivity, improved fairness, and high throughput. The key idea behind NOMA is to serve multiple users in the same resource block, such as a time slot, subcarrier, or spreading code. The NOMA principle is a general framework, and several recently proposed 5G multiple access schemes can be viewed as special cases. This survey provides an overview of the latest NOMA research and innovations as well as their applications. Thereby, the papers published in this special issue are put into the content of the existing literature. Future research challenges regarding NOMA in 5G and beyond are also discussed.