Affine frequency division multiplexing for next-generation wireless networks

Affine Frequency Division Multiplexing (AFDM) is a new multi-chirp waveform that can be generated and demodulated using the discrete affine Fourier transform (DAFT). DAFT is a generalization of discrete Fourier transform characterized with two parameters which can be adapted to better cope with both doubly dispersive channels and impairments at high-frequency bands. DAFT domain impulse response can indeed convey a full delay-Doppler representation of linear time-varying (LTV) channels, which allows AFDM to achieve the full diversity. Moreover, AFDM signals are maximally spread in time and frequency, thus providing a coverage gain that turns out to be robust against radio frequency impairments, such as carrier frequency offset and phase noise. In this paper, we show that AFDM offers the aforementioned advantages while being compatible with practical pilot-aided channel estimation and low-complexity channel equalization. Our analytical and simulation results evince that AFDM achieves significant throughput and reliability gains over state-of-the-art multicarrier modulation.