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.