5G meets Time Sensitive Networking
Connectivity will play an important role in factory automation and Industry 4.0. Reliable and secure transport of data in a timely manner is one of the key requirements on industrial communication technology. Time sensitive networking (TSN) defines a set of IEEE standards primarily developed for Ethernet. TSN is a promising enabler for satisfying the requirements, as is the 5G mobile technology, standardized by 3GPP. Our experts foresee that interworking of 5G and TSN will enable holistic communications for industrial automation.
Why 5G makes sense in an industrial environment
5G technology can reduce costs relating to the cabling infrastructure, support mobile units like autonomous carts or moving Automated Guided Vehicles (AGVs), and increasing flexibility in industrial applications.
In manufacturing, there is an increasing demand for custom made products, which drives a trend towards more flexible production sites.
With 5G, new production cells can be introduced without the need for cables. The new installations do not need to be at the same site, since 5G can support connectivity to remote sites. This allows connectivity of dispersed factories across different locations.
A brief introduction to the TSN world
The main goal of a Time Sensitive Network is to provide deterministic services over IEEE standard 802.3 Ethernet wired networks. This means guaranteed packet transport with low and bounded latency, low packet delay variation, and low packet loss. TSN features can be enabled for specific data streams in a network that also handles best effort type of traffic, for example, converged industrial networks, where data streams from different operations technology (OT) applications with varying timing requirements are carried together with information technology (IT) flows on the same network infrastructure.
TSN standards can be applied in many verticals, for example industrial automation and automotive in-vehicle networks. IEEE and the International Electrotechnical Commission (IEC) are together developing a so called dual logo standard to define TSN profiles for industrial automation: IEC/IEEE 60802. The following figure summarizes the potential TSN components and corresponding IEEE 802.1 standards for industrial automation.
Bringing the two worlds together, 5G integration with TSN
5G is the right solution to connect devices (industrial sensor/actuators) wirelessly to a TSN network. The new features of 5G, especially in the Radio Access Network (RAN), provide even better reliability and transmit latencies compared to 4G, and the new 5G system architecture allows flexible deployments. As a result, 5G can extend TSN networks to avoid the limitations of cable installations.
To support TSN services over 5G systems, the main challenge is to enable interworking of the TSN and 5G network. The below figure shows an example: how the 5G network expands a TSN wired network.
A machine is connected to the industrial controller via a 5G network. To support end-to-end Quality of Service (QoS), the 5G network requires strong inter-networking with TSN.
3GPP activities towards TSN
The first steps were taken with 4G enhancements to support low latency, in preparation for moving towards 5G. Our previous blog post, “LTE latency reductions: preparing for 5G”, gives details on how new techniques like fast uplink access reduces average radio delay by 50% in LTE.
In the 3GPP Release 15 specifications, further latency reductions were introduced or enhanced. Examples include flexible numerology, mini-slots, and fast acknowledgments that effectively support low-latency applications. Reliability was also improved by allowing the network to use duplications schemes and repetitions, including new antenna techniques introduced to enable URLCC in 5G New Radio (NR) – in essence, features to support TSN.
For Release 16, the 3GPP has started a new study on NR Industrial Internet of things (IIoT), targeting the integration of 5G and TSN networks. Ethernet services, TSN integration, further enhanced reliability, flexible uplink scheduling, precise time synchronization, and support for industrial automation traffic types are features included in the scope.
One of the key areas in Release 16 is to further enhance 5G system to satisfy the requirements of industrial applications supported by TSN. These are as described in 3GPP Technical Specification 22.261 on service requirements for the 5G systems. The focus is to provide new device capabilities to support time synchronization and dual connectivity. One example: according to the requirement specification, the time critical industrial application scenario might require latency of 1 millisecond, packet delay variation (jitter) of 1 microsecond, and reliability requirements of 99.9999%.
The summary of possible enablers for TSN over 5G are presented below.
Ericsson is currently a leading contributor in 5G standardization to introduce new features for TSN.