As a key technology for 5G, non-orthogonal multiple access (NOMA) can improve system capacity and connection densities. In this article, Release 16 study on NOMA in 3GPP is overviewed, which encompasses the transmitter side processing, receiver types and complexity, channel structure, and performance evaluations. Compared to the technical report of the NOMA study item, this article also highlights the relevant use cases and explains the performance relationship between link and system levels. In addition, the article touches some fundamental theory as well as very practical engineering. The aim is to provide readers a comprehensive picture of the technical essence of the NOMA study item, with insight into how to balance between cost, complexity, performance, and analytical pursuit. Some future directions are also provided.

中文翻译：

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3GPP 中的 5G 非正交多址研究

作为5G的关键技术，非正交多址（NOMA）可以提高系统容量和连接密度。在本文中，Release 16 对 3GPP 中 NOMA 的研究进行了概述，其中包括发射机侧处理、接收机类型和复杂性、信道结构和性能评估。相对于 NOMA 研究项目的技术报告，本文还重点介绍了相关用例，并解释了链路和系统级别之间的性能关系。此外，文章涉及一些基础理论以及非常实用的工程。目的是让读者全面了解 NOMA 研究项目的技术本质，深入了解如何在成本、复杂性、性能和分析追求之间取得平衡。还提供了一些未来的方向。