Affine Frequency Division Multiplexing (AFDM) for 6G: Properties, Features, and Challenges

TL;DR

AFDM is a promising 6G waveform with robustness, compatibility, and security features, suitable for high-mobility environments and integrated sensing, offering advantages over existing waveforms like OTFS and OFDM.

Contribution

This paper provides a comprehensive overview of AFDM's properties, features, and challenges, highlighting its potential as a 6G standardization candidate.

Findings

AFDM offers enhanced robustness in high-mobility environments.

It provides strong backward compatibility with OFDM.

AFDM enables physical-layer security through chirp parametrization.

Abstract

Affine frequency division multiplexing (AFDM) is an emerging waveform candidate for future sixth generation (6G) systems offering a range of promising features, such as enhanced robustness in heterogeneous and high-mobility environments, as well as inherent suitability for integrated sensing and communications (ISAC) applications. In addition, unlike other candidates such as orthogonal time-frequency space (OTFS) modulation, AFDM provides several unique advantages that strengthen its relevance to practical deployment and standardization in 6G. Notably, as a natural generalization of orthogonal frequency division multiplexing (OFDM), strong backward compatibility with existing conventional systems is guaranteed, while also offering novel possibilities in waveform design, for example to enable physical-layer security through its inherent chirp parametrization. In all, this article provides an overview of AFDM, emphasizing its suitability as a candidate waveform for 6G standardization. First, we provide a concise introduction to the fundamental properties and unique characteristics of AFDM, followed by highlights of its advantageous features, and finally a discussion of its potential and challenges in 6G standardization efforts and representative requirements.