Study of Clustered Robust Linear Precoding for Cell-Free MU-MIMO Networks

Fuente: arXiv
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Main Authors: Flores, A., de Lamare, R.
Format: Preprint
Published: 2024
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author Flores, A.
de Lamare, R.
author_facet Flores, A.
de Lamare, R.
contents Precoding techniques are key to dealing with multiuser interference in the downlink of cell-free (CF) multiple-input multiple-output systems. However, these techniques rely on accurate estimates of the channel state information at the transmitter (CSIT), which is not possible to obtain in practical systems. As a result, precoders cannot handle interference as expected and the residual interference substantially degrades the performance of the system. To address this problem, CF systems require precoders that are robust to CSIT imperfections. In this paper, we propose novel robust precoding techniques to mitigate the effects of residual multiuser interference. To this end, we include a loading term that minimizes the effects of the imperfect CSIT in the optimization objective. We further derive robust precoders that employ clusters of users and access points to reduce the computational cost and the signaling load. Numerical experiments show that the proposed robust minimum mean-square error (MMSE) precoding techniques outperform the conventional MMSE precoder for various accuracy levels of CSIT estimates.
format Preprint
id arxiv_https___arxiv_org_abs_2407_05517
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Study of Clustered Robust Linear Precoding for Cell-Free MU-MIMO Networks
Flores, A.
de Lamare, R.
Information Theory
Precoding techniques are key to dealing with multiuser interference in the downlink of cell-free (CF) multiple-input multiple-output systems. However, these techniques rely on accurate estimates of the channel state information at the transmitter (CSIT), which is not possible to obtain in practical systems. As a result, precoders cannot handle interference as expected and the residual interference substantially degrades the performance of the system. To address this problem, CF systems require precoders that are robust to CSIT imperfections. In this paper, we propose novel robust precoding techniques to mitigate the effects of residual multiuser interference. To this end, we include a loading term that minimizes the effects of the imperfect CSIT in the optimization objective. We further derive robust precoders that employ clusters of users and access points to reduce the computational cost and the signaling load. Numerical experiments show that the proposed robust minimum mean-square error (MMSE) precoding techniques outperform the conventional MMSE precoder for various accuracy levels of CSIT estimates.
title Study of Clustered Robust Linear Precoding for Cell-Free MU-MIMO Networks
topic Information Theory
url https://arxiv.org/abs/2407.05517