Beyond MMSE: Rank-1 Subspace Channel Estimator for Massive MIMO Systems

Fuente: arXiv
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Main Authors: Li, Bin, Wei, Ziping, Yang, Shaoshi, Zhang, Yang, Zhang, Jun, Zhao, Chenglin, Chen, Sheng
Format: Preprint
Published: 2024
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author Li, Bin
Wei, Ziping
Yang, Shaoshi
Zhang, Yang
Zhang, Jun
Zhao, Chenglin
Chen, Sheng
author_facet Li, Bin
Wei, Ziping
Yang, Shaoshi
Zhang, Yang
Zhang, Jun
Zhao, Chenglin
Chen, Sheng
contents To glean the benefits offered by massive multi-input multi-output (MIMO) systems, channel state information must be accurately acquired. Despite the high accuracy, the computational complexity of classical linear minimum mean squared error (MMSE) estimator becomes prohibitively high in the context of massive MIMO, while the other low-complexity methods degrade the estimation accuracy seriously. In this paper, we develop a novel rank-1 subspace channel estimator to approximate the maximum likelihood (ML) estimator, which outperforms the linear MMSE estimator, but incurs a surprisingly low computational complexity. Our method first acquires the highly accurate angle-of-arrival (AoA) information via a constructed space-embedding matrix and the rank-1 subspace method. Then, it adopts the post-reception beamforming to acquire the unbiased estimate of channel gains. Furthermore, a fast method is designed to implement our new estimator. Theoretical analysis shows that the extra gain achieved by our method over the linear MMSE estimator grows according to the rule of O($\log_{10}M$), while its computational complexity is linearly scalable to the number of antennas $M$. Numerical simulations also validate the theoretical results. Our new method substantially extends the accuracy-complexity region and constitutes a promising channel estimation solution to the emerging massive MIMO communications.
format Preprint
id arxiv_https___arxiv_org_abs_2404_13603
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Beyond MMSE: Rank-1 Subspace Channel Estimator for Massive MIMO Systems
Li, Bin
Wei, Ziping
Yang, Shaoshi
Zhang, Yang
Zhang, Jun
Zhao, Chenglin
Chen, Sheng
Information Theory
Signal Processing
To glean the benefits offered by massive multi-input multi-output (MIMO) systems, channel state information must be accurately acquired. Despite the high accuracy, the computational complexity of classical linear minimum mean squared error (MMSE) estimator becomes prohibitively high in the context of massive MIMO, while the other low-complexity methods degrade the estimation accuracy seriously. In this paper, we develop a novel rank-1 subspace channel estimator to approximate the maximum likelihood (ML) estimator, which outperforms the linear MMSE estimator, but incurs a surprisingly low computational complexity. Our method first acquires the highly accurate angle-of-arrival (AoA) information via a constructed space-embedding matrix and the rank-1 subspace method. Then, it adopts the post-reception beamforming to acquire the unbiased estimate of channel gains. Furthermore, a fast method is designed to implement our new estimator. Theoretical analysis shows that the extra gain achieved by our method over the linear MMSE estimator grows according to the rule of O($\log_{10}M$), while its computational complexity is linearly scalable to the number of antennas $M$. Numerical simulations also validate the theoretical results. Our new method substantially extends the accuracy-complexity region and constitutes a promising channel estimation solution to the emerging massive MIMO communications.
title Beyond MMSE: Rank-1 Subspace Channel Estimator for Massive MIMO Systems
topic Information Theory
Signal Processing
url https://arxiv.org/abs/2404.13603