Until the launch of 5G, every previous generation of mobile phone technology was primarily intended to improve the operation of the handset. It was not until 4G technology was adopted in 2008 that real smartphone capability was enabled and 4G mobile broadband led to the development of smartphone apps, a proliferation of multimedia and streaming services, and high-speed internet access on-the-go.
The installation today of 5G networks marks the first time that a new generation of mobile technology has been built around the needs of machines and systems rather than of handset users. The telecoms industry’s plan for 5G envisaged technical breakthroughs in three main parameters – latency, reliability and determinism; the density of connections; bandwidth, and speed of data transfer.
The reason for enhancing performance in these parameters was to enable real-time monitoring and control of dense concentrations of devices communicating concurrently.
The requirement for latency, density and bandwidth is met by three technology enhancements embodied in the 5G standard specifications. These are:
- Ultra-reliable low latency communication (URLLC) for real time-control systems.
- Enhanced mobile broadband (eMBB) to support new bandwidth-dependent use cases including augmented and virtual reality.
- Enhanced/massive machine type communications (eMTC) for low-power, wide-area wireless networking.
These features make 5G technology capable of supporting the requirements of factory control systems for real-time determinism and ‘six 9s’ (99.9999%) availability. Yet the real-world experience of most mobile handset users accessing 2G, 3G or 4G networks is still, to this day, of black spots where coverage is weak or non-existent, and of occasional and unpredictable dropped connections.
So is there a realistic prospect that mobile phone technology will be used to connect mission-critical, time-sensitive industrial machines?
Longevity of 4-20mA
For all the hype around state-of-the-art 5G technology, the reality is that most new process equipment installations today include provision for control via wired 4-20mA links – a proven, dependable technology. This speaks to industry’s need for certainty and the avoidance of risk when implementing mission- or safety-critical control systems.
The tides of change cannot be beaten back forever, and innovations in the way factories operate give control system designers good reason to evaluate 4-20mA alternatives. As Industry 4.0 accelerates the pace at which factory operations evolve, two trends are driving the introduction of new networking technologies: the introduction of autonomous mobile machinery, and the development of more flexible manufacturing facilities to meet growing consumer demand for personalized or configured products.
In factory and warehouse settings, the use of autonomous guided vehicles (AGVs), collaborative robots and other autonomous mobile devices offer an effective way to increase efficiency and productivity.
The new generation of autonomous mobile devices such as AGVs requires a wireless communications connection which offers low latency for real-time control, high bandwidth to carry the signals from multiple sensors such as LiDAR scanners and video cameras, and high immunity to interference – the hallmarks of 5G mobile networks.
When a factory operator replaces wired with wireless connections, they also gain the flexibility to reconfigure factory equipment quickly to meet new or varied demands from consumers. The rise of e-commerce has driven rising expectations from consumers for near-instant delivery of ordered products, and for the ability to choose from a wider range of product options than ever before. The ability to move production or process equipment more quickly and easily is growing in value. A fixed, wired communications infrastructure is less flexible than a wireless network to which equipment can connect from any location. Wireless networks also reduce the cost, inconvenience and technical difficulty involved in installing communications cabling.
Over the long term, then, factory operators are open to the benefits of wireless control capability alongside established wired communications technologies. In the immediate future, however, industry has to make a priority of its most important requirements, for high reliability and availability; security; robustness to cope with challenging industrial operating conditions; and ultra-low latency.
These factors underlie the longevity of the 4-20mA standard for factory communications. And, while factory operators are looking to replace 4-20mA technology, their focus today is on the implementation of the Time-Sensitive Networking (TSN) standard for wired industrial Ethernet communications, rather than for anything wireless.
TSN has emerged as the preferred standard for high-bandwidth, wired data communications in the factory, since it offers the ideal combination of reliability, robustness, a high data-transfer rate, low latency measured in microseconds, and easy integration with enterprise IT network systems.
Because the TSN specification is a standard benefiting from cross-industry support, it is rapidly developing a rich ecosystem of suppliers of TSN components and systems.
Validating the claims
Alongside the implementation of TSN networks, however, the scope for enhancing factory operations through the implementation of wireless networking is also coming under active evaluation. Some early adopters in the industrial community have already begun the work of testing, validating and evaluating the operation of 5G networking systems inside the factory, while concurrently replacing legacy 4-20mA systems with new TSN Ethernet networks. This validation process will find the most suitable applications for 5G technology.
So, factory operators are now starting to test innovative features of the 5G specification, such as ‘massive MIMO’ capability – the use of arrays of antennas to provide multiple physical transmission paths between transmitter and receiver. An array may be configured to form multi-antenna beams transmitting to multiple receivers. This allows the implementation of techniques such as channel hardening, beamforming, rapid channel estimation, and antenna (spatial) diversity, the effects of which are to dramatically improve reliability and reduce latency compared to 4G mobile networking.
One of the aims of the developers of the 5G standard was to enable wireless networks to achieve six 9s reliability for packet delivery, comparable to that of a wired Ethernet network, and equivalent to a packet error ratio of 1:1,000,000. Latency of 1ms is also possible, which is well within the limit imposed by many industrial control applications.
The question is, can this performance be achieved in the real-world conditions experienced inside a factory, where communications equipment might be subject to multiple sources of high-amplitude radio-frequency interference, transient voltage events, high temperatures and other disturbances?
In validating the real-world performance of a 5G installation, factory system designers have a choice: they can take advantage of 5G coverage provided by mobile network service providers. The 5G standard also makes provision for the implementation of private systems, or so called non-public networks (NPNs) covering, for example, an industrial campus or a large factory complex. Different industrial users and use cases will favor a different choice of public or private network.
The implementation of 5G networking in the factory is also facilitated by the development by mobile network operators of the OpenRAN (open radio access network) specification. This has opened up the market for 5G radio and core equipment to a broader range of suppliers in addition to those which have traditionally served the telecoms equipment market. This has the potential to broaden the choice of equipment available to meet the needs of use cases different from those of the mass-market public network operators, and to encourage the development of 5G products by suppliers which are focused on the industrial market.
While the immediate future clearly belongs to wired industrial Ethernet technology, it is easy to imagine a future in which AGVs and robots inside the factory transmit and receive time- and mission-critical data payloads via a 5G network – and the availability of 5G network coverage means that this is an actual rather than a theoretical possibility today.
To learn more about Radwell International
This article originally appeared on Control Engineering Europe
View the original article and related content on Control Engineering