DFT-spread Affine Frequency Division Multiplexing for Transmission over Doubly Dispersive Channels

Abstract

Affine Frequency Division Multiplexing (AFDM) has recently attracted substantial attention as a promising modulation scheme for high-mobility wireless environments because of its resilience to doubly dispersive channel effects. In this paper, we propose a DFT-spread AFDM framework and evaluate its effectiveness in mitigating impairments caused by doubly selective channels and in reducing the peak-to-average power ratio (PAPR). A detailed system model is developed, supported by mathematical analysis and comprehensive simulation studies. The performance of the proposed DFT-spread AFDM scheme is compared with conventional OFDM and OTFS waveforms. Simulation results show that DFT-spread AFDM significantly reduces the bit error rate (BER) across a wide range of signal-to-noise ratios (SNRs), primarily due to enhanced frequency diversity and lower PAPR. These gains are supported by comparative BER curves for conventional AFDM and DFT-spread AFDM, to-gether with the corresponding PAPR evaluations. These findings highlight the suitability of DFT-spread AFDM for high-mobility applications, such as UAV-assisted and railway communication systems, characterized by doubly selective channel conditions.