Developing NOMA to Next Generation Multiple Access: Future Vision and Research Opportunities

As a prominent member of the Next Generation Multiple Access (NGMA) family, Non-Orthogonal Multiple Access (NOMA) has been recognized as a promising multiple access candidate for the Sixth-Generation (6G) networks. This article focuses on applying NOMA in 6G networks, with an emphasis on proposing the so-called One Basic Principle Plus Four New concept. Successive Interference Cancellation (SIC) importance becomes evident, starting with the basic NOMA principle. In particular, this article discusses the advantages and drawbacks of channel-state-information-based SIC and quality-of-service-based-SIC. In addition, it explores applying NOMA to meet the new 6G performance requirements, especially for massive connectivity. Further, this article considers integrating NOMA with new physical layer techniques, followed by introducing new application scenarios for NOMA toward 6G. Finally, the article investigates applying machine learning in NOMA networks, ushering in the machine learning empowered NGMA era.

Introduction

According to the latest Visual Network Index report [1], the global mobile data traffic in 2022 will be seven-fold larger compared to 2017. In addition to this explosive data demand, emerging bandwidth-thirsty applications, for example, space-air-ground-integrated-networks (SAGINs), virtual reality (VR), augmented reality (AR), and so on, requiring strict quality-of-service (QoS) create further challenges for next-generation wireless networks.