RIS-assisted Multiuser MISO Transmission and the Impact of Imperfect Channel Estimation

Fuente: arXiv
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Hauptverfasser: Moreno-Locubiche, Ainna Yue, Vidal, Josep, Pascual-Iserte, Antonio, Muñoz, Olga
Format: Preprint
Veröffentlicht: 2026
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author Moreno-Locubiche, Ainna Yue
Vidal, Josep
Pascual-Iserte, Antonio
Muñoz, Olga
author_facet Moreno-Locubiche, Ainna Yue
Vidal, Josep
Pascual-Iserte, Antonio
Muñoz, Olga
contents This paper proposes the joint design of reconfigurable intelligent surfaces (RIS) and zero-forcing (ZF) precoding for the downlink (DL) multiuser multiple-input single-output (MU-MISO) setup in millimeter-wave (mmWave) bands, where ZF is particularly attractive due to its ability to suppress inter-user interference by exploiting the large antenna arrays and sparse directional channels characteristic of mmWave systems. This ensures efficient spatial multiplexing with manageable complexity, making ZF a practical and in modern 5G/6G deployments. However, a careful design is necessary to overcome potential rank deficiency in the channel matrix. For the MU-MISO case, rank deficiency may arise if users exhibit significantly different channel gains or if, being in far-field, they are aligned with the position of the transmitter. On the other hand, the deployment of a RIS introduces artificial scattering which can shape the radio environment to address those situations. We explore the joint design under perfect channel knowledge, assess the impact of imperfect channel estimation on the bit error rate (BER) and propose a robust design of pilot transmissions that equalizes multiuser interference across users in the presence of channel errors in the precoder design. This evaluation shows the advantages of optimized RIS-aided ZF MU-MISO communication for the DL of wireless systems.
format Preprint
id arxiv_https___arxiv_org_abs_2605_10660
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle RIS-assisted Multiuser MISO Transmission and the Impact of Imperfect Channel Estimation
Moreno-Locubiche, Ainna Yue
Vidal, Josep
Pascual-Iserte, Antonio
Muñoz, Olga
Signal Processing
This paper proposes the joint design of reconfigurable intelligent surfaces (RIS) and zero-forcing (ZF) precoding for the downlink (DL) multiuser multiple-input single-output (MU-MISO) setup in millimeter-wave (mmWave) bands, where ZF is particularly attractive due to its ability to suppress inter-user interference by exploiting the large antenna arrays and sparse directional channels characteristic of mmWave systems. This ensures efficient spatial multiplexing with manageable complexity, making ZF a practical and in modern 5G/6G deployments. However, a careful design is necessary to overcome potential rank deficiency in the channel matrix. For the MU-MISO case, rank deficiency may arise if users exhibit significantly different channel gains or if, being in far-field, they are aligned with the position of the transmitter. On the other hand, the deployment of a RIS introduces artificial scattering which can shape the radio environment to address those situations. We explore the joint design under perfect channel knowledge, assess the impact of imperfect channel estimation on the bit error rate (BER) and propose a robust design of pilot transmissions that equalizes multiuser interference across users in the presence of channel errors in the precoder design. This evaluation shows the advantages of optimized RIS-aided ZF MU-MISO communication for the DL of wireless systems.
title RIS-assisted Multiuser MISO Transmission and the Impact of Imperfect Channel Estimation
topic Signal Processing
url https://arxiv.org/abs/2605.10660