5G is being hailed as the key to Industry 4.0 and commercial public networks are already beginning to roll out with great fanfare. Unfortunately, what often isn’t said is that 5G’s specific industrial features are not expected to be part of the 5G standard until 2021. Even then, there will be a lag as 5G chip and device vendors bring industrial 5G devices to market. Add a few more years before they are integrated into production processes and stabilized for commercial deployment and it looks as if 5G is at least five to six years away for most manufacturers. So, do you put your Industry 4.0 plans on hold?
As the title of this piece suggests, you can still get started today with 4G/LTE private wireless. Many industrial applications can be supported on 4G/LTE. In effect, with a single network, 4G/LTE can support:
- High-bandwidth mobile broadband applications such as video-based quality control or AR assembly assistance
- Low data rate, long battery life IoT communications with narrowband IoT (NB-IoT)
- Adding new sensors to old machines with LTE-M
- Worker critical communication such as PMR-type applications like Push-To-Talk (PTT) and Push-to-Video (PTV)
- Low-latency industrial applications such as remote operations of machines and vehicles.
Private LTE network solutions with various deployment options are available today and new spectrum is being released in a number of countries specifically to support it.
But CAT cables are secure and predictable — why then make the move to wireless? To start with, connecting lots of machines, sensors, workers, and moving assets is either difficult or just plain impossible without wireless. In effect, there are quite a few applications around the factory floor that need wireless, such as next-generation autonomous guided vehicles (AGVs), smart connected tools, wearable sensors, and smart personal protective equipment (PPE). But even for non-mobile applications that need to be digitalized, the cost of wiring is significant (e.g., factory IoT sensors for monitoring and predictive maintenance of brownfield machines). Just like at home, a wireless alternative to Ethernet makes things a lot simpler and helps cut costs.
Wi-Fi is an alternative, but even the pending Wi-Fi 6 standard will not satisfy all the network performance requirements for business- and mission-critical communications. Wi-Fi was designed for home and business office LAN connectivity. It is a best-effort networking protocol that doesn’t provide the reliability, security, latency, and quality control of IP/MPLS over Ethernet. 4G/LTE and 5G, in contrast, can provide comparable performance. Recognizing this, more and more manufacturers have already made the move to 4G/LTE.
Security. While Wi-Fi is notoriously insecure, LTE provides end-to-end security through encryption together with a robust ciphering algorithm and IPSec from the device to the network. All devices and users on the network are securely authorized and authenticated using SIM cards or an embedded SIM (eSIM) that cannot be removed.
Interference and reliability. LTE is designed specifically to deal with interference while Wi-Fi has a “round-robin” type scheduler that deals with it by avoiding it, which isn’t always possible in busy industrial settings without creating significant latencies (see discussion below). The LTE cell scheduler prioritizes radio resources in both frequency and time domains within milliseconds to maximize radio efficiencies. With private LTE in a manufacturing setting, the devices, the cellular network and applications all are self-contained, and the radio environment is very well understood (as compared, for instance, with a public network with varying traffic loads/patterns). Thus, very high reliability levels, up to 99.999% (five 9s) uptime, can be achieved.
Better spectrum options. Today’s Wi-Fi shares its spectrum with many other applications in either the 2.4 GHz or 5 GHz bands. This is okay for typical office environments. However, in manufacturing environments, there is a lot more potential interference. Private LTE networks can be deployed using a number of available frequency bands, either in partnership with an operator through leasing arrangements, or using one of the other shared or unlicensed band options. Even using shared CBRS bands in the US (3.5 GHz) or unlicensed band options, such as MulteFire (5 GHz), LTE coverage area is approximately twice that of Wi-Fi and reliability remains much higher.
Consistent latency/throughput. Business-critical communications in manufacturing environments require predictable latency and consistent throughput, especially for automation. Because LTE is designed with a robust scheduler, the typical latency experienced in private LTE is between 9 to 15 ms and, with new LTE advancements, latencies of 2 to 8 ms will be possible. As discussed, with Wi-Fi’s priority allocation, latencies on the network will vary widely depending on the number of devices attached that are simultaneously transmitting data. Wi-Fi throughput can drop by 90 to 95 percent with up to 15 s latencies seen in congested, noisy environments or during hand-over.
Scalability. LTE provides significantly higher device density per small cell than Wi-Fi access points, again due to its robust time and frequency domain scheduler. Commercially available small cells can support in excess of 800 simultaneously active devices. Wi-Fi cannot support more than 30-50 connected devices before its throughput plummets.
One of the key characteristics of Industry 4.0 is the extensive use of Industrial IoT (IIoT). Think of thousands of devices having to be connected to the wireless network all actively communicating at the same time. These could include…
- Asset tracking for tools
- Spare parts and inventory
- Environmental monitoring
- Condition-based monitoring of existing machines to measure performance
- Autonomous AGVs
- Digital personal protective equipment (PPE)
The list goes on. Wi-Fi is not designed to scale for this, whereas private LTE, capable today of reliably supporting 100k-plus spectators tightly squeezed in a stadium, has proven its capabilities when it comes to lots of connected devices with heavy broadband loads.
IIoT is a key part of Industry 4.0, but there are other advantages to having robust and reliable wireless connectivity on the factory floor. 4G/LTE can replace Ethernet or extend CAT cables’ reach for many applications providing a compelling use case for many manufacturers. More frequencies are becoming available with governments allocating new or shared bands and unlicesned bands freed up for industrial use. Finally, private, industrial-strength wireless connectivity with 4G/LTE is as easy or easier to install and operate as a Wi-Fi network. It gets your Industry 4.0 transformation started with plenty of room to grow and is designed to transition, when the time comes, to 5G.
David Nowoswiat is a sr. product and solutions marketing manager for Nokia.
