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arXiv · 2511.12308

ISAC with Affine Frequency Division Multiplexing: An FMCW-Based Signal Processing Perspective

Jiajun Zhu·Yanqun Tang·Cong Yi·Haoran Yin·Yuanhan Ni·Fan Liu·Zhiqiang Wei·Huseyin Arslan
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Abstract

This paper investigates the sensing potential of affine frequency division multiplexing (AFDM) in high-mobility integrated sensing and communication (ISAC) from the perspective of radar waveforms. We introduce an innovative parameter selection criterion that establishes a precise mathematical equivalence between AFDM subcarriers and Nyquist-sampled frequency-modulated continuous-wave (FMCW). This connection not only provides a clear physical insight into AFDM's sensing mechanism but also enables a direct mapping from the DAFT index to delay-Doppler (DD) parameters of wireless channels. Building on this, we develop a novel input-output model in a DD-parameterized DAFT (DD-DAFT) domain for AFDM, which explicitly reveals the inherent DD coupling effect arising from the chirp-channel interaction. Subsequently, we design two matched-filtering sensing algorithms. The first is performed in the time-frequency domain with low complexity, while the second is operated in the DD-DAFT domain to precisely resolve the DD coupling. Simulations show that our algorithms achieve effective pilot-free sensing and demonstrate a fundamental trade-off between sensing performance, communication overhead, and computational complexity. The proposed AFDM outperforms classical AFDM and other variants in most scenarios.

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Jiajun Zhu, Yanqun Tang, Cong Yi, Haoran Yin, Yuanhan Ni, Fan Liu, Zhiqiang Wei, Huseyin Arslan. 2025-11-15. ISAC with Affine Frequency Division Multiplexing: An FMCW-Based Signal Processing Perspective. https://arxiv.org/abs/2511.12308

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