Affine Frequency Division Multiplexing for 6G Networks: Fundamentals, Opportunities, and Challenges

Sixth-generation (6G) are expected to introduce new usage scenarios, along with enhanced and new capabilities. In 6G networks, high-mobility communications that enjoy high reliability and operate at high carrier frequencies will play a critical role. However, orthogonal frequency division multiplexing, widely used in current wireless networks, suffers from significant performance degradation in high-mobility scenarios, since frequency dispersion resulting from Doppler shifts destroys the subcarrier orthogonality and causes inter-carrier interference. Therefore, this article highlights a recently proposed modulation scheme, called affine frequency division multiplexing (AFDM), which can achieve the optimal diversity order over doubly dispersive channels. Specifically, after revisiting the characteristics of doubly dispersive channels, we present the fundamentals of AFDM, and describe a range of potential AFDM applications for future wireless networks. Finally, some open challenges in the practical implementation of AFDM are discussed. The purpose of this article is to attract greater attention from both academia and industry to AFDM, with the intention of advancing its practical applications in upcoming 6G networks.