Index Modulation Multiple Access for 6G Communications: Principles, Applications, and Challenges

Index modulation multiple access (IMMA) is a promising sixth-generation (6G) technique to prominently improve the spectral efficiency, energy efficiency, system performance, and support massive connectivity, which is considered as a new extension of conventional non-orthogonal multiple access (NOMA). In this article, we first introduce the basic principle of IMMA, and then investigate the potential applications of IMMA to vehicular networks, reconfigurable intelligent surface (RIS) aided networks, cooperative networks, and secure networks, which demonstrate the flexibility and practicability of IMMA. Finally, we reveal some potential challenges and research opportunities for IMMA. This article aims to draw more attention from academia and industry to IMMA and intends to promote the practical implementation of IMMA in future 6G networks.