5G technology in manufacturing can enable a more flexible, versatile and efficient usage of production assets, including robots, by shifting the intelligence to the cloud and controlling the devices wirelessly. However, achieving very low cycle times in the range of milliseconds for real-time control of such applications is still a major challenge in currently available 5G networks. In this work, we present a test setup that uses a control-split approach which allows to operate a robotic arm with a variable cycle time by using a piece-wise spline interpolation on the motion trajectory. We verified functionality of this approach over a private 5G network deployed in a factory. Measurement results on the network performance and the robot trajectory accuracy are presented. Our results show that the proposed robot control implementation operates reliably even under high network utilization due to background traffic with only moderate tracking error.

Ethernet-based industrial communication standards are dominating the communication landscape in factories. With the transition towards more flexible and wireless solutions, there is a strong interest to enable existing wired applications, such as control-to-control (C2C) use cases, over a wireless network. In this work, we investigate an example C2C application and validate its performance when operated over 5G. For this purpose, we present measurement results taken from a 5G standalone (SA) deployment in an operational factory. Our results show that 5G can replace existing wired solution, but at the cost of a lowered C2C application efficiency due to longer network latency. We furthermore investigate the impact of cross-traffic to the C2C application and effects of traffic prioritization.

Synchronization is a major aspect in converged wired and wireless time-sensitive networks. Heterogeneous synchronization mechanisms are involved. From an end-to-end perspective, the synchronization of the 5G radio access network between base station and user equipment, is the major source of inaccuracy due to uncertain transmission characteristics. It uses a propagation delay compensation based on a timing advance measurement. We propose a novel propagation delay compensation which uses multiple timing advance measurements to estimate the user equipment position and in that way it is able to achieve a more accurate propagation delay compensation. We compare our proposal with ongoing discussions of improving the propagation delay compensation by enhancing the timing advance granularity.

A key aspect of 5G is the facilitation of network convergence. It enables the support of a broad range of use cases including real-time applications over the same shared network infrastructure. One major challenge in addressing the various latency requirements is the efficient sharing of resources for heterogeneous services under the presence of different scheduling timescales. State-of-the-art solutions propose preemptive approaches to satisfy instantaneous time-critical demands, which however can deteriorate the communication for preempted users as well as the overall rate efficiency in the network. We propose a slicing method tailored for deterministic traffic, as commonly found in industrial applications. By exploiting deterministic properties of resource demands, we determine an optimal share of reserved and preempted resources on a per-slot basis to efficiently satisfy all time-critical demands. Additionally, we introduce a preemption restricted slice to protect users with higher reliability requirements. Under this proposed model, we derive an online scheduling algorithm which maintains a better fairness and higher throughput compared to state-of-the-art solutions under high demand of deterministic traffic.

Wireless control applications will play a fundamental role in future factory environments to enable novel mobility use cases and achieve the desired flexibility in production. The standardized integration of 5G into a time-sensitive networking (TSN) environment defines the joint architecture and communication interfaces between the different networks to support time-critical applications. Managing and scheduling such a network in an end-to-end fashion to guarantee the stringent QoS requirements is however a complex task. In this work, we present an efficient window-based resource allocation method for the end-to-end network. A big challenge in scheduling periodic and time-critical control applications over a wireless system is the uncertainty of the channel. We hence introduce a fading correlation-aware optimization to find robust schedules. Our simulation study shows that this approach is able to reduce peak resource demands and hence improve the schedulability compared to standard channel-unaware TSN scheduling.

The integration of 5G with Time-Sensitive Networking (TSN) promises to support the novel requirements of future industrial communication. A key aspect for the industrial application of converged TSN/5G networks is synchronization. Different synchronization scenarios can be identified which are directly affiliated with a particular grandmaster location. The state-of-the-art scenario is a network-sided grandmaster. We propose an novel synchronization scenario which uses a common grandmaster for both the wired and wireless networks. This uniforms the synchronization in converged networks. Our proposed approach achieves a largely improved synchronization towards device-sided devices while introducing only a minor additional error towards network-sided devices. We present and compare our proposal with the state-of-the-art synchronization scenarios, and conduct a formal analysis to estimate the synchronization quality per scenario and simulations to verify the results.

Many industrial players are currently challenged in building distributed CPS and IoT applications with stringent end-to-end QoS requirements. Examples are Vehicle-to-X applications, Advanced Driver-Assistance Systems (ADAS) or functionalities in the Industrial Internet of Things (IIoT). Currently, there is no comprehensive solution allowing to efficiently program, deploy, and operate such distributed applications. This paper will focus on real-time concerns, in building distributed CPS and IoT systems. Thereby, the focus lies, on the one hand, on mechanisms required inside of the IoT (compute) nodes, and, on the other hand, on communication protocols such as TSN and 5G connecting them. In the authors' view, the required building blocks for a first end-to-end technology stack are available. However, their integration into a holistic framework is missing.

While the industry is continuously evolving towards more flexible and modular manufacturing environments, simultaneously requirements on the industrial network infrastructure are changing. Network convergence, flexibility in configuration with support of hard real-time end-to-end guarantees are playing a key role. A technology supporting these features is Time-sensitive Networking (TSN). The extension with TSN-over-5G to additionally support mobile use cases brings us one step closer towards a unified and converged wireless and wired network architecture, as needed for future manufacturing environments. At the same time, management and configuration of such large converged networks to guarantee real-time capabilities becomes inherently complex. In this work, we present a joint configuration approach that enables end-to-end scheduling optimization over a bridged network consisting of TSN and logical 5G bridges. We derive suitable network constraints and optimization strategies and apply constraint programming to determine feasible scheduling solutions. By providing numerical results from a simulative study, we show the effectiveness of our proposed end-to-end framework in terms of resource efficiency and support of concurrent users in the network.

Converged wired and wireless networks promise to meet both real-time and mobility requirements of factory automation scenarios. Time-Sensitive Networking (TSN) and 5G are auspicious technologies for future industrial communication. Hence, the combination of both wired and wireless communication is extensively discussed for industrial use cases. In this paper, we analyze the time synchronization in realistic wired and converged wired and wireless networks through IEEE 802.1AS. We provide a formulation of the time synchronization mechanisms and a system model for IEEE 802.1AS. Moreover, we investigate the synchronization accuracy for TSN and 5G/TSN networks given the requirements from IEEE, 3GPP, and IEC/IEEE.

Future factory automation scenarios require real-time capable communication networks and most recently expose great demand for mobile and scalable communication. A promising solution is the convergence of wired and wireless networks in order to merge the benefits of both wired and wireless technologies. The industry emphasizes TSN and 5G as technologies for future communication networks. The seamless integration of 5G with TSN as virtual TSN bridge is a focus topic of the 3GPP and IEEE standardization groups. However, the distribution of timing information through converged TSN/5G networks has not yet been investigated.In this work, we propose and analyze a single message mechanism for distribution of timing information in converged TSN/5G networks under consideration of 3GPP and IEEE standard documents.