Affine Frequency Division Multiplexing: Extending OFDM for Scenario-Flexibility and Resilience

Next-generation wireless networks are designed to provide reliable, high-data-rate communication services for diverse scenarios such as vehicle-to-vehicle, unmanned-aerial-vehicle, and satellite networks. Large Doppler spreads in the underlying time-varying channels induce destructive inter-carrier interference (ICI) in the widely adopted orthogonal frequency-division multiplexing (OFDM) waveform, leading to severe performance degradation. This calls for a new air-interface design that can accommodate the severe delay–Doppler spreads of highly dynamic channels while offering sufficient flexibility to cater to various applications. This article provides a comprehensive overview of a promising chirp-based waveform, Affine Frequency Division Multiplexing (AFDM). Featuring two tunable parameters, AFDM achieves the optimal diversity order in doubly dispersive channels (DDC). We examine the fundamental principles of AFDM, illustrating its intrinsic suitability for DDC; on this basis, several potential applications are explored. Furthermore, the main challenges of AFDM and their corresponding solutions are presented, followed by key directions for future research. Finally, we draw instructive conclusions about AFDM to provide useful insights for its continued development.