Low-Complexity Channel Estimation for RIS-Assisted Multi-User Wireless Communications
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arXiv
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| Auteurs principaux: | , , , , |
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| Format: | Preprint |
| Publié: |
2025
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| _version_ | 1866929684060569600 |
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| author | Li, Qingchao El-Hajjar, Mohammed Hemadeh, Ibrahim Shojaeifard, Arman Hanzo, Lajos |
| author_facet | Li, Qingchao El-Hajjar, Mohammed Hemadeh, Ibrahim Shojaeifard, Arman Hanzo, Lajos |
| contents | Reconfigurable intelligent surfaces (RISs) are eminently suitable for improving the reliability of wireless communications by jointly designing the active beamforming at the base station (BS) and the passive beamforming at the RIS. Therefore, the accuracy of channel estimation is crucial for RIS-aided systems. The challenge is that only the cascaded two-hop channel spanning from the user equipments (UEs) to the RIS and spanning from the RIS to the BS can be estimated, due to the lack of active radio frequency (RF) chains at RIS elements, which leads to high pilot overhead. In this paper, we propose a low-overhead linear minimum mean square error (LMMSE) channel estimation method by exploiting the spatial correlation of channel links, which strikes a trade-off between the pilot overhead and the channel estimation accuracy. Moreover, we calculate the theoretical normalized mean square error (MSE) for our channel estimation method. Finally, we verify numerically that the proposed LMMSE estimator has lower MSE than the state-of-the-art (SoA) grouping based estimators. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2501_12773 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Low-Complexity Channel Estimation for RIS-Assisted Multi-User Wireless Communications Li, Qingchao El-Hajjar, Mohammed Hemadeh, Ibrahim Shojaeifard, Arman Hanzo, Lajos Information Theory Signal Processing Reconfigurable intelligent surfaces (RISs) are eminently suitable for improving the reliability of wireless communications by jointly designing the active beamforming at the base station (BS) and the passive beamforming at the RIS. Therefore, the accuracy of channel estimation is crucial for RIS-aided systems. The challenge is that only the cascaded two-hop channel spanning from the user equipments (UEs) to the RIS and spanning from the RIS to the BS can be estimated, due to the lack of active radio frequency (RF) chains at RIS elements, which leads to high pilot overhead. In this paper, we propose a low-overhead linear minimum mean square error (LMMSE) channel estimation method by exploiting the spatial correlation of channel links, which strikes a trade-off between the pilot overhead and the channel estimation accuracy. Moreover, we calculate the theoretical normalized mean square error (MSE) for our channel estimation method. Finally, we verify numerically that the proposed LMMSE estimator has lower MSE than the state-of-the-art (SoA) grouping based estimators. |
| title | Low-Complexity Channel Estimation for RIS-Assisted Multi-User Wireless Communications |
| topic | Information Theory Signal Processing |
| url | https://arxiv.org/abs/2501.12773 |