The integration of IoT technology into industrial environments has sparked a new industrial revolution that seeks to create smart, automated processes. But current wireless internet technologies such as Wi-Fi will not be able to handle the mass integration of such IoT devices. Thus another technology, LTE (4G), provides a possible alternative.

IIoT Processes

While industrial processes have undergone many changes over the years, the introduction of IoT technologies has triggered an industrial revolution, Industry 4.0. The ability to gather mass amounts of information from all aspects of every single industrial process provides engineers with invaluable data that, if combined with AI technologies, can a smart system. Such as system would be able to minimise waste by making different processes work better with each other, it would be able to adjust task times to provide better flow between different production steps, and it would give predictive capabilities which can not only determine when a piece of machinery may require maintenance but also adjust its use to maximise lifespan and reduce machine downtime. The gathering of such data can also provide critical insight into the final quality of products and factors that are often not considered to be necessary could be linked. 

Achieving such a goal requires large amounts of data from every possible process, and getting data between these processes and a central control system requires an internet connection. Processes that are fixed in place can rely on wired Ethernet connections which are both high-speed and easily allow for large numbers of devices connected to a single network, but processes that are mobile or have a degree of movement cannot rely on such wired technologies. In these instances, wireless technology is required, which allows for a mobile device to retain a network connection while on the move. One standard connection method that currently exists is Wi-Fi which is found in most homes, offices, and industrial sites but the many limitations of Wi-Fi make it far from ideal for future IIoT use.

The Faults Of Wi-Fi

Wi-Fi as wireless internet technology is practical for home and offices, but when implemented into industrial environments quickly becomes impractical. The first issue that Wi-Fi presents is the maximum number of supported devices which is 255 in an ideal world (this is often lower depending on the network controller used and other devices that are connected to the network via LAN). While most homes rarely have more than a handful of WI-Fi devices, an industrial unit can easily reach this maximum if all process are connected via Wi-FI as well as transportation stages and floor workers. 

The second issue that Wi-Fi suffers from is its bandwidth, whose peak data transfer rate is 300mbps. This bandwidth is perfectly adequate for houses with four or five Wi-Fi devices, but an industrial location with over 200 devices will quickly see the download speed of each device dramatically drop and thus be unsuitable. While 5GHz Wi-Fi can increase this to 900mpbs, the range is significantly reduced as 2.4GHz signals can travel further than 5GHz (see radio propagation vs wavelength). This is where the third issue comes in, range, which Wi-Fi suffers from poorly. While Wi-Fi does have a stated maximum range of  46 meters, this is in good conditions (i.e. open-air with no obstacles), and industrial environments can easily be far more significant than this thus requiring multiple access points with the use of Wi-Fi repeaters. The use of repeaters demonstrates the fourth issue with Wi-Fi; repeaters do not provide flawless roaming. When a device falls out of range of a Wi-Fi network, it has to perform a reconnect to the next Wi-Fi network that is now in range which can be lengthy and unreliable. Anything mobile (such as an automated forklift) and requires a constant uplink to a control system will periodically lose connection during network changeovers and not be able to function reliably or safely. 

Overall, Wi-Fi is low bandwidth, low device count technology that is suitable for homes and offices but not for locations which involve hundreds of internet-enabled devices that may roam between different networks. This is where another technology is proving to be ideal, LTE.

Private LTE

4G LTE is a cellular technology that is deployed globally for mobile connections and provides both cellular phone calls as well as the internet. However, recent government moves such as the FCC opening up the 4G band has resulted in telecommunication companies start to implement private LTE networks for large corporations and industry partners to aid with the growth of IIoT and automation. But why is LTE a superior technology than Wi-Fi, and are there any real-world examples of its integration?

To understand why LTE is an appropriate technology when compared to Wi-Fi it is best first to understand what environment LTE is deployed in. In order for mobile communications to be practical, the network that they connect to needs to be able to handle a few criteria. The first is that the network needs to be wireless with a range that removes the need for an access point every few hundred meters. The second requirement is that those who move from one cell network to the next can do so with no noticeable effects such as call drop or connection loss. The third requirement is that the network can handle large loads with as many as several thousand devices connected to a single cell. All of these criteria are easily met with 4G thanks to its cellular range being up to 45 miles,  up to 1200 devices being supported at once, and data speed rates up to 150mbps. 4G networks also support advanced features such as MIMO allowing for a large number of simultaneous connections, beam forming to improve signal connections to devices, and roaming capabilities whereby a device moving from one LTE cell to the next has no effect on connection performance. 

When LTE technologies are applied to IIoT applications, it quickly becomes apparent that it is a highly suitable technology. The ability to have robotic systems move between cells with no performance loss, many thousands of devices simultaneously sending and receiving data, and a range that can reliably cover an entire industrial facility. The use of such technology also reduces complexity when compared to a Wi-Fi setup as a private 4G network may only require a single mast whereas a Wi-Fi-based system would require frequent access points all connected to a single network (possible via Ethernet). The use of a single mast also helps to improve security by keeping the number of access points minimised whereas Wi-Fi routers typically have default passwords, no protection over Ethernet, can be snooped to determine passwords, and a large number of access points increases the likely hood that one is configured incorrectly providing an entry point for cybercriminals.

Conclusion

The use of private LTE networks is currently ongoing with major telecommunication companies such as Nokia and Cisco working hard to implement them into all environments ranging from hospitals to mining. The advantages that private LTE offers far outweighs its cons of price and complexity, especially when compared to technologies such as Wi-Fi which are designed for lightweight use only. The future of automation will be heavily reliant on reliable communications that will need to be wireless and until private LTE becomes mainstream the world of IIoT will have to continue on relying on Wi-Fi but will only realise its full potential when LTE is established.