ORBIT-DT: Bridging Simulation and Reality with Digital Twin Design for O-RAN in Beyond 5G Networks

The increasing diversity of vertical applications in Beyond 5G (B5G) networks has driven widespread adoption of wireless network emulators for developing and evaluating innovative solutions. However, the effectiveness of these solutions heavily depends on the precise parameters configuration, accurate network model design, and the fidelity of the emulation process. Furthermore, achieving real-time resource allocation for heterogeneous traffic remains a significant challenge. To address these complexities, the Open Radio Access Network (O-RAN) concept has gained prominence, leveraging enhanced programmability of RAN functionalities to enable data-driven, intelligent control loops in cellular networks. In this context, we propose ORBIT-DT, an Open RAN-Based Intelligent Twin - Digital Twin, to address the challenges of accurate modeling and resource allocation in B5G networks. Leveraging the open-source Colosseum platform, we design and emulate the ORBIT-DT of POWDER, a publicly available over-the-air sub-6GHz indoor/outdoor testbed. Through extensive experiments, we validate the performance of the proposed ORBIT-DT across various wireless scenarios including eMBB, mMTC, and URLLC slices, comparing it with its Physical Twin (PT). Results demonstrate the ORBIT-DT's ability to support large-scale data collection and achieve a high degree of fidelity, with an average similarity of up to 98.8% in downlink throughput, underscoring its effectiveness as a realistic and reliable representation of the PT.