IEEE Journal Article on the Digital Triplet for Reliable 6G C-ITS Systems Published

Future Cooperative Intelligent Transport Systems (C-ITSs) will rely on mobile networks that provide low latency, high data rates, and reliable communication despite rapidly changing wireless channel conditions. Testing these systems, however, remains challenging: simulations are highly reproducible and scalable but cannot capture every real-world effect, whereas experiments with full-scale vehicles offer high physical realism but are costly, difficult to reproduce, and subject to safety constraints.

To address this challenge, the article implements the Digital Triplet concept proposed earlier [1]. It interconnects three complementary domains: a full-scale real-world test field, a scaled-down physical replica, and a virtual co-simulation environment. Real, scaled, and simulated vehicles can interact within synchronized scenarios, allowing communication, computation, and vehicle-control solutions to be evaluated at different levels of abstraction. Compared with previous partial implementations [2], the presented architecture advances the Digital Triplet toward a complete cross-domain test environment by integrating the full-scale research vehicle “karl.” [3] and interconnecting a larger fleet of upgraded scaled vehicles via private 5G/O-RAN infrastructure.

The Digital Triplet is demonstrated using two demanding C-ITS applications: remote driving and cooperative vehicular platooning. For remote driving, a full-scale research vehicle and customized 1:10-scale RoboRacer vehicles are connected to modular operator workplaces via public, commercial private, and O-RAN-based private mobile networks. An optimized low-latency video-streaming system based on the RISE concept [4] achieves median Glass-to-Glass latencies below 100 ms. Compared with a related local network deployment, the median Glass-to-Glass latency is reduced by up to 74% despite transmission over a mobile network. At the same time, detailed latency analysis shows that the network delays remain a crucial target for optimization, for example, through the 6GEM+ concept O-RACES [5]. The virtual environment additionally enables the investigation of future millimeter-wave communication systems and Reconfigurable Intelligent Surfaces before the corresponding network infrastructure is available in the test field.

For cooperative platooning, real-world vehicle-localization characteristics are emulated in the scaled test field and combined with a cross-domain Nonlinear Model Predictive Control approach. The controller coordinates lateral and longitudinal vehicle motion and is evaluated in both decentralized configurations, where calculations are performed on the vehicles, and centralized configurations using an edge-cloud system. By combining physical experiments with virtual vehicles and obstacles, complex cooperative-driving scenarios can be investigated safely and repeatedly before being transferred to full-scale deployments.

The results demonstrate the potential of the Digital Triplet to bridge the gap between simulation and real-world experimentation. By combining the scalability and reproducibility of simulation with the physical behavior of scaled platforms and the realism of full-scale vehicles, the framework can accelerate the development and validation of reliable C-ITS applications for future 6G networks.

The work was conducted jointly by researchers from the Chair of Communication Networks and the Chair of Design Automation of Embedded Systems at TU Dortmund University, the Institute for Automotive Engineering at RWTH Aachen University, and the Lamarr Institute for Machine Learning and Artificial Intelligence. The successful collaboration provides a strong foundation for further joint research on reliable 6G-enabled mobility applications within the ongoing 6GEM+ transfer hub.

A video demonstration of the Digital Triplet is available under tiny.cc/digitaltriplet.

Published Article
H. Schippers, N. A. Wagner, L. Reiher, H. Teper, L. Ostendorf, J-J. Chen, L. Eckstein, C. Wietfeld., “Digital Triplet for Developing Future Reliable 6G Cooperative Intelligent Transport Systems: Case Studies from Teleoperation to Platooning, ” In IEEE Access, vol. 14, pp. 89380-89403, June 2026. DOI: 10.1109/ACCESS.2026.3702246. [pdf]  [IEEE Xplore] [Video] [Details]

Acknowledgment
This work has received funding by the German Federal Ministry of Research, Technology and Space (BMFTR) in the course of the research hub 6GEM, the transfer hub 6GEM+, and the GEM-X project under grant numbers 16KISK038, 16KIS2412, and 16KISS005.

Additional References
[1] H. Schippers, C. Schüler, B. Sliwa, C. Wietfeld, "System Modeling and Performance Evaluation of Predictive QoS for Future Tele-Operated Driving", In 2022 Annual IEEE International Sys­tems Conference (SysCon), Virtual Event, April 2022. [pdf] [bibtex] [Details]
[2] C. Krieger, H. Teper, J. Freytag, I. Priyanta, P. Schulte, M. Roidl, J.-J. Chen, C. Wietfeld, "Integration of Scaled Real-world Testbeds with Digital Twins for Future AI-enabled 6G Networks", In 2023 IEEE Globecom Workshops (GC Wkshps), Workshop on Intelligent 6G Architecture: towards network simplicity and autonomy (Int6GArch), Kuala Lumpur, Malaysia, December 2023. [pdf] [Details]
[3] J.-P. Busch, L. Ostendorf, G. Linden, L. Reiher, T. Beemelmanns, B. Lampe, T. Woopen, and L. Eckstein, ‘‘karl. – A research vehicle for automated and connected driving’,’ in Proc. IEEE Intelligent Vehicles Symposium (IV), Detroit, USA, Jun. 2026.
[4] H. Schippers, T. Gebauer, K. Heimann, C. Wietfeld, "RISE: Multi-Link Proactive Low-Latency Video Streaming for Teleoperation in Fading Channels," in IEEE 101st Vehicular Technology Conference (VTC-Spring), Oslo, Norway, June 2025. [pdf] [video] [Details] 
[5] N. A. Wagner, C. Wietfeld, "O-RACES: Proactive AI-driven scheduling in Open RAN for 6G-networked humanoid robots," in IEEE INFOCOM Workshops, NetRobiCS Workshop on Networked Robotics and Communication Systems, Tokyo, Japan, May 2026. (Best Paper Award) (Forthcoming) [pdf] [Video] [Details]