EM-Based Channel Estimation for mMIMO LEO SATCOM Under Imperfect Doppler Compensation

Fuente: arXiv
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Auteurs principaux: Darya, Abdollah Masoud, Abdallah, Saeed
Format: Preprint
Publié: 2025
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author Darya, Abdollah Masoud
Abdallah, Saeed
author_facet Darya, Abdollah Masoud
Abdallah, Saeed
contents Massive multiple-input multiple-output low-Earth-orbit communication channels are highly time-varying due to severe Doppler shifts and propagation delays. While satellite-mobility-induced Doppler shifts can be compensated using known ephemeris data, those caused by user mobility require accurate user positioning information; the absence of such information contributes to amplified channel aging in conventional channel estimators. To address this challenge, we propose a data-aided channel estimator based on the expectation-maximization (EM) algorithm, combined with a discrete Legendre polynomial basis expansion model (DLP-BEM), to estimate the channel under imperfect Doppler compensation. The EM algorithm iteratively exploits hidden data symbols for improved channel estimation, while DLP-BEM regularizes the process by projecting the channel estimate onto a lower-dimensional subspace that mitigates estimation errors. Simulation results demonstrate the superiority of the proposed framework over existing methods in terms of normalized mean square error and symbol error rate.
format Preprint
id arxiv_https___arxiv_org_abs_2505_14118
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle EM-Based Channel Estimation for mMIMO LEO SATCOM Under Imperfect Doppler Compensation
Darya, Abdollah Masoud
Abdallah, Saeed
Signal Processing
Massive multiple-input multiple-output low-Earth-orbit communication channels are highly time-varying due to severe Doppler shifts and propagation delays. While satellite-mobility-induced Doppler shifts can be compensated using known ephemeris data, those caused by user mobility require accurate user positioning information; the absence of such information contributes to amplified channel aging in conventional channel estimators. To address this challenge, we propose a data-aided channel estimator based on the expectation-maximization (EM) algorithm, combined with a discrete Legendre polynomial basis expansion model (DLP-BEM), to estimate the channel under imperfect Doppler compensation. The EM algorithm iteratively exploits hidden data symbols for improved channel estimation, while DLP-BEM regularizes the process by projecting the channel estimate onto a lower-dimensional subspace that mitigates estimation errors. Simulation results demonstrate the superiority of the proposed framework over existing methods in terms of normalized mean square error and symbol error rate.
title EM-Based Channel Estimation for mMIMO LEO SATCOM Under Imperfect Doppler Compensation
topic Signal Processing
url https://arxiv.org/abs/2505.14118