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Main Authors: Bui, Duc Tung, Tran, Le-Nam
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2509.25512
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author Bui, Duc Tung
Tran, Le-Nam
author_facet Bui, Duc Tung
Tran, Le-Nam
contents We present the first implementation of a Multi-User Multiple-Input Multiple-Output (MU-MIMO) transmission scheme on the Physical Downlink Shared Channel (PDSCH) for 5G Open Radio Access Network (O-RAN) based on OpenAirInterface (OAI). Our implementation features a fully functional O-RAN-compliant 5G New Radio (5G NR) system, including a 5G Core Network (5G CN), a refined 5G RAN, which is split into a Centre Unit (CU) and an Distributed Unit (DU), and 5G NR User Equipment (UEs). This implementation demonstrates MU-MIMO performance in the downlink while showcasing the disaggregation capabilities of O-RAN. Specifically, the Base Station (i.e. gNB) in our setup is capable of serving two UEs simultaneously over the same downlink Resource Block (RBs). User scheduling is performed based on the Precoding Matrix Indicators (PMIs) reported by the UEs according to the NR Channel State Information (CSI) reporting procedure. The system throughput performance is evaluated using $\textit{iperf}$. The obtained results via simulation and testbed experiments demonstrate that the MU-MIMO scheme achieves significant downlink throughput gains, particularly in the high Signal-to-Noise-Ratio (SNR) regime, while keeping the Block Error Rate (BLER) below the required threshold of $10^{-1}$ for both UEs.
format Preprint
id arxiv_https___arxiv_org_abs_2509_25512
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle An Implementation of Multi-User MIMO Downlink for O-RAN 5G New Radio using OpenAirInterface
Bui, Duc Tung
Tran, Le-Nam
Signal Processing
We present the first implementation of a Multi-User Multiple-Input Multiple-Output (MU-MIMO) transmission scheme on the Physical Downlink Shared Channel (PDSCH) for 5G Open Radio Access Network (O-RAN) based on OpenAirInterface (OAI). Our implementation features a fully functional O-RAN-compliant 5G New Radio (5G NR) system, including a 5G Core Network (5G CN), a refined 5G RAN, which is split into a Centre Unit (CU) and an Distributed Unit (DU), and 5G NR User Equipment (UEs). This implementation demonstrates MU-MIMO performance in the downlink while showcasing the disaggregation capabilities of O-RAN. Specifically, the Base Station (i.e. gNB) in our setup is capable of serving two UEs simultaneously over the same downlink Resource Block (RBs). User scheduling is performed based on the Precoding Matrix Indicators (PMIs) reported by the UEs according to the NR Channel State Information (CSI) reporting procedure. The system throughput performance is evaluated using $\textit{iperf}$. The obtained results via simulation and testbed experiments demonstrate that the MU-MIMO scheme achieves significant downlink throughput gains, particularly in the high Signal-to-Noise-Ratio (SNR) regime, while keeping the Block Error Rate (BLER) below the required threshold of $10^{-1}$ for both UEs.
title An Implementation of Multi-User MIMO Downlink for O-RAN 5G New Radio using OpenAirInterface
topic Signal Processing
url https://arxiv.org/abs/2509.25512