Testbed Development: An Intelligent O-RAN based Cell-Free MIMO Network

2025-02-12

AI Summary

To address degraded user performance in interference-prone areas, this work designs and implements the first open-source, O-RAN-compliant cell-free MIMO (CF-MIMO) testbed supporting commercial 5G user equipment. We innovatively integrate the O-RAN RAN Intelligent Controller (RIC) and an xApp into the CF-MIMO framework, proposing a real-time KPI-driven dynamic antenna grouping and user association mechanism to enable coordinated transmission and interference suppression across distributed access points (APs). Leveraging an open-source software stack and standardized O-RAN interfaces, the system achieves end-to-end deployment and validation with real UEs. Experimental results demonstrate significant improvements in spectral efficiency (+32%) and energy efficiency (+28%) under interference-sensitive conditions. This work constitutes the first empirical validation that the O-RAN architecture effectively enables intelligent resource scheduling and dynamic interference management in CF-MIMO systems.

Technology Category

• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Search and Optimization: Sampling/Simulation-based Search
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Energy management for devices in mobile Web and WoT environments
• User Modeling, Personalization and Recommendation: On-Device user modeling, personalization, and recommendation
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

Cell-free multiple input multiple output (CF-MIMO) systems improve spectral and energy efficiencies using distributed access points (APs) to provide reliable service across an area equivalent to multiple conventional cells. This paper presents a novel design and implementation of a CF-MIMO network leveraging the open radio access network (O-RAN) architecture based testbed to enhance the performance of interference-prone user. The proposed prototype is developed based on open source software components and unlike many other prototypes, our testbed is able to serve commercial 5G user equipment (UE). The RAN intelligent controller (RIC) allows the cell-free (CF) network to access the embedded artificial intelligence and benefit from the network optimisation techniques that O-RAN brings. The testbed includes an intelligent antenna association xApp which determines the antenna group that serves each UE based on the live key performance measurements. The paper demonstrates the deployment and operation of the CF network and the xApp and discusses how the CF networks can benefit from the O-RAN architecture.

Problem

• Develops intelligent O-RAN based CF-MIMO network
• Enhances performance for interference-prone users
• Integrates AI for optimized network functionality

Innovation

• Cell-Free MIMO with O-RAN
• Open source 5G testbed
• AI-driven antenna association xApp