The demand for precise time synchronization is of great interest in contemporary networked systems, especially in the context of converged networks where seamless communication among devices, actuators, and sensors is imperative. This has led to the development and adoption of Time-Sensitive Networking (TSN) and Wireless TSN (WTSN) technologies, with a particular attention to the IEEE 802.1AS Generalized Precision Time Protocol (gPTP) standard. In this work, we explore the role of time synchronization in a wireless network scenario involving an Unmanned Ground Vehicle (UGV) that has to track a desired time dependent trajectory. The UGV receives trajectory waypoints from a secondary station, emphasizing the importance of precise timing in trajectory tracking. Utilizing the IEEE 802.1AS standard for wireless time synchronization, this study investigates the impact of clock synchronization errors and latency on trajectory tracking. Hence, it demonstrates the capability and benefits of IEEE 802.1AS in managing device clocks and facilitating time correction to ensure precise trajectory tracking despite synchronization errors and latency.

The ever more used and widespread Time-Sensitive Networking (TSN) has changed real-time networks, enabling reliable communication for time-critical applications. At the same time Software-Defined Networking (SDN) has emerged as a solution to ensure proper quality of service for managing dynamic network configurations even in evolving topologies. This paper investigates the integration between TSN and SDN to enable dynamic network re-configuration and improve performance for time-critical applications. We present an experimental setup designed to evaluate this approach. The setup focuses on scenarios where an SDN controller can dynamically reroute critical data flows across different TSN network devices to avoid interference and maintain consistent Quality-of-Service (QoS).

High reliability wireless communications for mission-critical applications often necessitates path diversity through redundant channels. In this context, we explore the combination of the IEC 62439 High-availability Seamless Redundancy (HSR) architecture with IEEE 802.1CB Frame Replication and Elimination for Reliability (FRER) features. While HSR is well-established for wired networks, both HSR and FRER aim to enhance network reliability through redundancy. However, the HSR algorithm assumes frame ordering, which is impractical in wireless networks due to packet ordering and time-based elimination challenges. To address this, we propose integrating the IEEE 802.1CB vector recovery algorithm within the HSR framework. We focus on Wireless Local Area Networks (WLANs), where we modify an existing HSR implementation in Linux to operate over wireless channels. Our experimental analysis demonstrates significant improvements in latency metrics compared to non-redundant communications subject to interfering traffic. The proposed implementation targets industrial applications, such as robotic feedback control with stringent two-millisecond latency deadlines. By considering latency and out-of-order delivery—features not well-supported by the current HSR standard, we demonstrate improved reliability and latency characteristics required for demanding real-time control applications utilizing wireless as a principal communications medium.

Managing Wireless networks, particularly in industrial and factory environments, to meet the escalating demands of time critical applications has become more complex and warrants proactive management strategies. This work introduces an innovative approach to wireless network management enabled by a Digital Twin (DT) designed and continuously enhanced by real-time device telemetry and user inputs through an Extended Reality interface. By collecting real telemetry data from network devices, our methodology defines and calibrates a DT representation of the network, enabling accurate prediction of wireless signal properties and network performance based on simulation models. The DT serves as an automation tool to analyze various scenarios, allowing for informed adjustments to user applications, devices and network configurations. The paper describes a real-life DT implementation of a wireless system in a real enterprise network scenario. Experimental results are provided demonstrating improved performance and user experience enabled by the proposed DT-based network management. The proposed methodology addresses the challenges of real-time network optimization and contributes to advance wireless network management based on device and network telemetry.

The introduction of Time-Sensitive Networking (TSN) is revolutionizing real-time networks and time-critical applications. Recent advancements in this field extended the TSN capabilities to wireless technologies, giving rise to the concept of wireless TSN (WTSN). This paper focuses on the integration of wireless TSN with Software-Defined Networking (SDN) to enable dynamic network configuration and improve the performance of time-sensitive applications. We present a practical test environment that uses a hybrid network configuration consisting of wireless and wired TSN links. The primary objective is to evaluate the effectiveness of combining a TSN-capable network with an SDN controller. This setup enables dynamic configuration and routing within the system, allowing for prompt actions to address network issues, such as seamlessly re-routing data paths between the two links due to an increase in latency or packet loss. A measurement setup using OpenVSwitch in the wireless TSN domain is presented, along with the evaluation of time synchronization and dynamic route selection capabilities.

Industrial Internet of Things (IIoT) use cases have stringent reliability and latency requirements to enable real-time wireless control systems, which are supported by the 5G ultra-reliable low-latency communications (URLLC). However, extremely high quality-of-service (QoS) requirements in 5G URLLC causes huge radio resource consumption and low spectral efficiency, thus limiting network capacity in terms of the number of supported devices. Industrial control applications typically incorporate redundancy in their design and may not always require extreme QoS to achieve the expected control performance. Therefore, we propose both communication-control co-design and dynamic QoS to address the capacity issue for robotic manipulation use cases in 5G-based IIoT. We have developed an advanced co-simulation framework that includes a network simulator, physics simulator, and compute emulator, for realistic performance evaluation of the proposed methods. Through simulations, we show significant improvements in network capacity (i.e., the number of supported URLLC devices), and about 2x gain for the robotic manipulation use case.

Time-sensitive networking (TSN) is emerging as a viable means to achieving deterministic quality of service (QoS) communications within mission critical industrial applications such as feedback control systems, robotics, and precision sensing and actuation. Originally developed for Ethernet-based audio-video applications using the User Datagram Protocol (UDP). TSN assume unidirectional flows from source (talked) to destination(listener) and it is most easily implemented using UDP in which packets are transmitted without an acknowledgment from the recipient. However, most existing industrial protocols are implemented using the reliable Transport Control Protocol (TCP) in which each transmission is explicitly acknowledged. In this work, a bandwidth efficient TSN schedule is developed to accommodate the TCP traffic flow between two synchronized robots collaboratively moving an object. We then demonstrate an IEEE 802.1Qbv TSN schedule over an IEEE 802.11 wireless medium that guarantees robot performance requirements are maintained while accommodating concurrent best-effort traffic flows. The process for schedule selection and experimental data collection is discussed, and TSN configuration parameter tuning and experimental results are provided.

Mobile and autonomous robots are among the most critical technology applications requiring wireless connectivity with deterministic performance, including bounded latency with high reliability, even under congested network conditions. Emerging Wireless Time-Sensitive Networking (WTSN) capabilities over Wi-Fi and 5G can enable time synchronization and bounded low latency through time-aware scheduling mechanisms. Such Wireless TSN capabilities have been demonstrated in several industrial/robotic use cases, but under static conditions. Mobility introduces new challenges due to the roaming events and associated network outages owing to signaling between client devices and network infrastructure during these events. In this paper, we show how we can take advantage of the TSN redundancy capability (as defined in the IEEE 802.1CB standard) to eliminate outages or delays due to events like roaming and interference in a mobile robot use case enabled by Wi-Fi 6 TSN. We demonstrate the roaming performance with no delay impact on the applications though simulations of a mobile robot in a factory scenario and experimental results with a mobile robot connected via multiple Wi-Fi 6 radios in a warehouse environment.

Time-sensitive networking (TSN) is an emerging topic for the advancement of wireless networking for industrial applications. TSN, as defined under the umbrella of IEEE 802.1 working group standards, addresses issues related to providing deterministic communications over IEEE 802-based Local Area Networks (LANs). TSN was originally designed to support real-time audio/video applications over Ethernet providing better reliability and lower, more deterministic latency with traffic shaping capabilities. TSN has since expanded its scope and applicability to other applications such as those in industrial environments and automotive applications. Industrial examples include machine-machine communications for robot control, end-effector actuation, real-time sensing, and safety integrated systems. Applications utilizing a wireless local area network (WLAN) can also benefit from scheduling and traffic shaping as defined in the 802.1Qbv standard; however, factors such as clock stability, synchronization, resource requirements and protocol options come into play when selecting a schedule to support multiple application types on the same network. In this article, we present a scenario for a collaborative robot heavy lift operation, in which, two robots communicate over an IEEE 802.11 WLAN with TSN capabilities to lift a rigid body in three dimensions. Scheduling is performed using 802.1Qbv over WLAN with the robot operating system (ROS) used as the software middleware utilizing the transport control protocol (TCP). As a part of the research, we describe our process for schedule selection to accommodate the time-sensitive traffic of the robotic scenario while allowing an industrial internet of things (IIoT) high data rate traffic to coexist. We then provide an analysis of the impacts of TSN schedule selection on the operational performance of the collaborative robot application.

In this article, we describe a methodology and associated models to evaluate a time sensitive collaborative robotics application enabled by wireless time sensitive networking (WTSN) capabilities. We also present a method to configure WTSN scheduling to meet the application time budget and validate it in a realistic industrial use case. We detail the methodologies for implementing and characterizing the performance of key WTSN capabilities, namely time synchronization and time-aware scheduling, over an IEEE 802.11 based network. We deploy the WTSN capabilities with a collaborative robotic workcell consisting of two robotic arms, which emulate a material handling application, known as machine tending. We further explore configurations and measurement methodologies to characterize application performance of this use case and correlate it to the performance of the wireless network.

In this paper, we describe a collaborative robotic workcell testbed enabled by Wireless Time Sensitive Networking (WTSN) technologies and discuss deployment, performance measurement and management guidelines challenges. We detail the methodologies for implementing and characterizing the performance of key WTSN capabilities (time synchronization and time-aware scheduling) over IEEE 802.11/Wi-Fi. We deployed WTSN capabilities on the National Institute of Standards and Technology (NIST) collaborative robotic workcell testbed consisting of two robotic arms that emulates a material handling application, known as machine tending. We further explore configurations and measurement methodologies to characterize Quality of Experience (QoE) of this use case and correlate it to the performance of the wireless network.