A Low-Complexity Joint Fractional Delay and Doppler Frequency Estimator for AFDM-Enabled Vehicular LEO-ICAN Systems

Fuente: arXiv
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Hauptverfasser: Chen, Zhenyu, Xiao, Ke, Tang, Xiaomei, Lei, Jing, Yuan, Muzi, Sun, Guangfu
Format: Preprint
Veröffentlicht: 2026
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author Chen, Zhenyu
Xiao, Ke
Tang, Xiaomei
Lei, Jing
Yuan, Muzi
Sun, Guangfu
author_facet Chen, Zhenyu
Xiao, Ke
Tang, Xiaomei
Lei, Jing
Yuan, Muzi
Sun, Guangfu
contents Low-Earth-orbit (LEO) satellites and vehicle-to-everything (V2X) networks are driving integrated communication and navigation (ICAN) toward next-generation intelligent transportation. Affine frequency division multiplexing (AFDM) is a promising waveform for high-mobility LEO scenarios owing to its Doppler robustness, simple modulation, and low pilot overhead. However, applying existing high-accuracy AFDM fractional delay-Doppler estimators to LEO-ICAN entails substantial search or inference complexity, while the spectrum-wrapping-induced envelope structure in line-of-sight (LOS)-dominated channels remains underexploited. This paper analyzes and exploits the spectrum-wrapping-induced envelope structure of the fractional AFDM response, and proposes a low-complexity joint estimator that combines minimum-entropy fractional Doppler estimation with closed-form fractional delay estimation. Simulation results show that the proposed estimator approaches the root Cramér--Rao lower bound (RCRLB) and achieves root-mean-square error (RMSE) performance comparable to that of matched filtering (MF), matched filtering with generalized Fibonacci search (MF-GFS), and off-grid sparse Bayesian learning (OG-SBL), while requiring substantially lower computational complexity and runtime. This favorable accuracy-complexity profile highlights the potential of the proposed estimator for real-time ICAN processing in high-mobility LEO-assisted vehicular networks.
format Preprint
id arxiv_https___arxiv_org_abs_2602_04316
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A Low-Complexity Joint Fractional Delay and Doppler Frequency Estimator for AFDM-Enabled Vehicular LEO-ICAN Systems
Chen, Zhenyu
Xiao, Ke
Tang, Xiaomei
Lei, Jing
Yuan, Muzi
Sun, Guangfu
Signal Processing
Low-Earth-orbit (LEO) satellites and vehicle-to-everything (V2X) networks are driving integrated communication and navigation (ICAN) toward next-generation intelligent transportation. Affine frequency division multiplexing (AFDM) is a promising waveform for high-mobility LEO scenarios owing to its Doppler robustness, simple modulation, and low pilot overhead. However, applying existing high-accuracy AFDM fractional delay-Doppler estimators to LEO-ICAN entails substantial search or inference complexity, while the spectrum-wrapping-induced envelope structure in line-of-sight (LOS)-dominated channels remains underexploited. This paper analyzes and exploits the spectrum-wrapping-induced envelope structure of the fractional AFDM response, and proposes a low-complexity joint estimator that combines minimum-entropy fractional Doppler estimation with closed-form fractional delay estimation. Simulation results show that the proposed estimator approaches the root Cramér--Rao lower bound (RCRLB) and achieves root-mean-square error (RMSE) performance comparable to that of matched filtering (MF), matched filtering with generalized Fibonacci search (MF-GFS), and off-grid sparse Bayesian learning (OG-SBL), while requiring substantially lower computational complexity and runtime. This favorable accuracy-complexity profile highlights the potential of the proposed estimator for real-time ICAN processing in high-mobility LEO-assisted vehicular networks.
title A Low-Complexity Joint Fractional Delay and Doppler Frequency Estimator for AFDM-Enabled Vehicular LEO-ICAN Systems
topic Signal Processing
url https://arxiv.org/abs/2602.04316