A DAFT Based Unified Waveform Design Framework for High-Mobility Communications

TL;DR

This paper introduces a unified waveform design framework for high-mobility communications based on the discrete affine Fourier transform (DAFT), enabling improved bit error rate performance through parameter adjustment.

Contribution

It proposes a novel DAFT-based unified framework that encompasses existing waveforms like OTFS, OCDM, and AFDM for high-mobility scenarios.

Findings

DAFT-based waveform performance improves at high SNR with parameter tuning.

Unified framework simplifies design of multi-carrier waveforms for high-mobility.

Enhanced diversity and robustness in high-mobility channels.

Abstract

With the increasing demand for multi-carrier communication in high-mobility scenarios, it is urgent to design new multi-carrier communication waveforms that can resist large delay-Doppler spreads. Various multi-carrier waveforms in the transform domain were proposed for the fast time-varying channels, including orthogonal time frequency space (OTFS), orthogonal chirp division multiplexing (OCDM), and affine frequency division multiplexing (AFDM). Among these, the AFDM is a strong candidate for its low implementation complexity and ability to achieve optimal diversity. This paper unifies the waveforms based on the discrete affine Fourier transform (DAFT) by using the chirp slope factor "k" in the time-frequency representation to construct a unified design framework for high-mobility communications. The design framework is employed to verify that the bit error rate performance of the DAFT-based waveform can be enhanced when the signal-to-noise ratio (SNR) is sufficiently high by adjusting the chirp slope factor "k".