Wireless Time Sensitive Networking (TSN) Capabilities and KPIs for Industrial, Pro AV and XR Applications

Time-Sensitive Networking (TSN) is a set of standards which define how a network should be made timing-aware and enable deterministic communication for time-sensitive data. These standards continue to add features to upgrade existing networks (wireless and wired) – including time synchronization and deterministic latency, robustness, and resource management for time critical applications.

As a part of the IEEE 802 family standards that defines Local Area Networks, such as Ethernet and 802.11 (Wi-Fi), wireless TSN has a lot of potential to make networking fundamentally better. It offers high reliability, plug-and-play user friendliness, and guaranteed latency. These features are required for both the advanced use cases futurists envision for Web 3.0 and Industry 4.0, as well as to serve the needs of today’s AV, automotive, avionic, and industrial applications.

Despite the broad need for wireless TSN, implementation has been scattershot. Before TSN multiple industries have created isolated modified Ethernet and Wi-Fi networks to serve their unique use cases. That fragmentation constrains systems interoperability and stands to slow the growth of the entire TSN ecosystem. Wireless TSN brings the opportunity to leverage core capabilities and interoperable implementations that can support multiple use cases and markets. TSN already benefits a wide range of verticals, and wireless TSN will expand those use cases significantly.

The Avnu Alliance, an organization dedicated to driving industry change and creating an interoperable ecosystem of networked devices using the open IEEE TSN standards, recently produced a whitepaper examining market expectations for wireless TSN capabilities, KPIs, and plans for testing and certification titled Wireless TSN: Market Expectations, Capabilities, & Certification. The results of the whitepaper indicate that converged networks with TSN capabilities are not just desirable, but entirely possible.

WTSN priority use cases

The Wireless TSN: Market Expectations, Capabilities, & Certification whitepaper identifies three priority use cases for wireless TSN: ProAV, Industrial Automation, and AR/VR. The list is not exhaustive, just likely where one can expect to see the first-to-market implementations:

• ProAV:This market currently uses TSN for live audio networking. Enabling Wireless TSN would allow flexibility and mobility of instruments, wearable devices, speakers, and equipment, including controls for pyrotechnics, moving stage/set elements, lights, etc.
• Industrial Automation:The primary TSN application here is communication between robots and a control system, including guidance control, process data, video/images, and emergency stop command. Wireless TSN would allow the wireless control of autonomous mobile robots (AMR) automated guided vehicles (AGV), or other mobile robots.
• AR / VR: Augmented Reality and Virtual Reality applications would greatly benefit from wireless TSN’s guaranteed latency features to reduce nausea resulting from high latency or lack of sync between haptics, audio, and interactive graphics. Wireless connectivity is a key requirement to enable highest usability – the user experience for these applications drastically declines when you’re required to wear a bunch of wired-together components that are then tethered to a console or computer.

Priority capabilities for wireless TSN

Time synchronization, as defined by the IEEE 802.1AS protocol, addresses time accuracy requirements from different applications. Accuracy on the order of 1µsec is a feasible goal over wireless systems, including 5G and Wi-Fi, and it should be expected to cover many wireless use cases.

Traffic shaping is currently defined under 802.1Qbv (Time-aware shaper) for industrial and 802.1Qav (credit-based shaper) for ProAV. 802.1Qbv is expected to be used in most industrial use cases where deterministic data delivery is required. Future ProAV networks may continue to use 802.1Qav in legacy wireless segments but could use 802.1Qbv traffic shaping for wireless segments.

Redundant streams with 802.1CB FRER including wired and wireless links.

In some high-reliability applications (e.g., safety-critical industrial automation applications), traffic delays, lost packets, device and link failures are unacceptable. TSN redundancy, as specified in the IEEE 802.1CB Frame Replication and Elimination for Reliability (FRER) standard, has been defined to enhance reliability by using data replication on multiple streams and paths. The 802.1CB FRER service is transparent to the underlying MAC/PHY link, and it should be able to operate over wireless links.

Wireless TSN KPIs by use case

Across the ProAV, Industrial Automation and AR/VR use cases outlined in the Avnu whitepaper, the wireless TSN KPIs are tightly clustered. We see the necessity for FRER in closed loop control applications, as well as broadly similar time synchronization and bounded latency (which drives traffic shaping requirements) KPIs across applications. This is not to say that Industrial Automation is the same as VR gaming – but it’s undeniable that the two very different applications benefit similarly from TSN capabilities and have similar deterministic performance needs.

The case for convergence

We can recognize that markets have unique needs without fragmenting the entire network landscape or segmenting off all time-sensitive traffic so that it remains forever a niche application. Silicon, software, and device manufacturers can use the base-level common capability and performance requirements to design broadly applicable, interoperable products that can be specialized by market from that common starting point. Wireless TSN applications – indeed, all TSN applications - are more likely to flourish if they can function as part of a standard converged network. Industries working from the same common basis can also share ideas and tools, leading to faster innovation.

How Avnu Alliance supports convergence

The purpose and mission of the Avnu Alliance is to transform standard networks to enable support for many time-sensitive applications and protocols in an open, interoperable manner.  Avnu both builds on the work of, as well as partners alongside, organizations developing protocols and standards that will use TSN across markets. Avnu is participating in the TSN Industrial Automation Conformance Collaboration (TIACC), a collaboration with CC-Link Partner Association, ODVA, OPC Foundation, and PROFIBUS & PROFINET International to develop a single common conformance test plan for the IEC/IEEE 60802 profile of TSN for Industrial Automation.

Avnu develops test specifications for TSN features and is currently working on the integration and validation of IEEE 802.1AS time synchronization and 802.1Qbv test development for both wired and wireless connectivity, with a certification program targeted to open for members this year.

Avnu also hosts plugfest events where vendors can further develop and test wired and wireless TSN products and devices and learn from one another. They also create specifications dedicated to professional audio endpoints to fill in the interoperability gaps for the Milan ProAV market.

Conclusion

Wireless TSN has the potential to drive the next great networking evolution, making advanced applications not only easier to build but more useful and more reliable. The potential for broad convergence at the base transportation level exists. Such convergence would accelerate the adoption of TSN and speed innovation across applications. Avnu invites interested companies to join us in making that happen.