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arXiv · 2604.07680

Low-complexity Frequency Domain Equalization for filtered-AFDM over General Physical Channels

Cheng Shen·Chenyang Zhang·Jinhong Yuan
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Abstract

Affine frequency division multiplexing (AFDM) has emerged as a promising waveform for high-mobility communications. However, its equalization remains a practical challenge under general physical channels with off-grid delay and Doppler effects. In this paper, we investigate frequency domain equalization for AFDM by considering a practical filtered-AFDM waveform. We analyze the input-output relations of filtered-AFDM across various domains and show that off-grid effects lead to severe inter-symbol interference in the DAFT domain, limiting the effectiveness of DAFT domain equalization. Motivated by the compactness of the frequency domain channel matrix in wideband systems, we propose a low-complexity two-stage frequency domain equalization scheme. Numerical results demonstrate that the proposed approach achieves performance close to full-block LMMSE equalization with significantly reduced computational complexity, and offers clear advantages over time domain equalization in wideband scenarios.

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Cheng Shen, Chenyang Zhang, Jinhong Yuan. 2026-04-09. Low-complexity Frequency Domain Equalization for filtered-AFDM over General Physical Channels. https://arxiv.org/abs/2604.07680

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