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Main Authors: Yi, Qin, Yang, Ping, Liu, Zilong, Sui, Zeping, Xiao, Yue, Wu, Gang
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2603.29218
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author Yi, Qin
Yang, Ping
Liu, Zilong
Sui, Zeping
Xiao, Yue
Wu, Gang
author_facet Yi, Qin
Yang, Ping
Liu, Zilong
Sui, Zeping
Xiao, Yue
Wu, Gang
contents This paper presents a dual-domain low-complexity expectation propagation (EP) detection framework for affine frequency division multiplexing (AFDM) systems. By analyzing the structural properties of the effective channel matrices in both the time and affine frequency (AF) domains, our key observation is the domain-specific quasi-banded sparsity patterns, including AF-domain sparsity under frequency-selective channels and time-domain sparsity under doubly-selective channels. Based on these observations, we develop an AF-domain EP (EP-AF) detector for frequency-selective channels and a time-domain EP (EP-T) detector for doubly-selective channels, respectively. By performing iterative inference in the time domain using the Gaussian approximation, the proposed EP-T detector avoids inverting the dense channel matrix in the AF domain. Furthermore, the proposed EP-AF and EP-T detectors leverage the aforementioned quasi-banded sparsity of the AF domain and time domain channel matrices, respectively, to reduce the complexity of matrix inversion from cubic to linear order. Simulation results demonstrate that the proposed low-complexity EP-AF detector achieves nearly identical error rate performance to its conventional counterpart, while the proposed low-complexity EP-T detector offers an attractive trade-off between detection performance and complexity.
format Preprint
id arxiv_https___arxiv_org_abs_2603_29218
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A Novel Low-Complexity Dual-Domain Expectation Propagation Detection Aided AFDM for Future Communications
Yi, Qin
Yang, Ping
Liu, Zilong
Sui, Zeping
Xiao, Yue
Wu, Gang
Signal Processing
This paper presents a dual-domain low-complexity expectation propagation (EP) detection framework for affine frequency division multiplexing (AFDM) systems. By analyzing the structural properties of the effective channel matrices in both the time and affine frequency (AF) domains, our key observation is the domain-specific quasi-banded sparsity patterns, including AF-domain sparsity under frequency-selective channels and time-domain sparsity under doubly-selective channels. Based on these observations, we develop an AF-domain EP (EP-AF) detector for frequency-selective channels and a time-domain EP (EP-T) detector for doubly-selective channels, respectively. By performing iterative inference in the time domain using the Gaussian approximation, the proposed EP-T detector avoids inverting the dense channel matrix in the AF domain. Furthermore, the proposed EP-AF and EP-T detectors leverage the aforementioned quasi-banded sparsity of the AF domain and time domain channel matrices, respectively, to reduce the complexity of matrix inversion from cubic to linear order. Simulation results demonstrate that the proposed low-complexity EP-AF detector achieves nearly identical error rate performance to its conventional counterpart, while the proposed low-complexity EP-T detector offers an attractive trade-off between detection performance and complexity.
title A Novel Low-Complexity Dual-Domain Expectation Propagation Detection Aided AFDM for Future Communications
topic Signal Processing
url https://arxiv.org/abs/2603.29218