1. Home
  2. Blog
  3. What Lies Beneath

What Lies Beneath


Reliable functioning of city infrastructure will become even more critical after COVID-19. That makes wireless condition monitoring essential

Nordic Semiconductor

City living was once replete with simple pleasures. A cup of coffee at a café with friends. Mingling among crowds in a vibrant town square. The excitement of exploring an immense urban metropolis.

Sadly, COVID-19 has radically reshaped city life, placing many of these pleasures on hold, at least for now. In their place, lockdowns and social distancing – the inhibiting but necessary precautions for containing a virulent disease. But now, vaccines are rolling out and residents are daring to dream of the old city life.

Yet it’s not a given that cities can effortlessly resume normal function. Even before COVID-19, moving large numbers of people around was hard. Much depends on crucial machinery working reliably – on equipment like elevators, escalators, travelators and conveyors ceaselessly churning, turning and shunting crowds back- and-forth over sprawling geographies and up-and-down towering urban centers.

In a post COVID-19 world, this critical equipment will have to work even harder and smarter. Among other things, transit systems now must account for social distancing. There are more trips to make because of fewer people allowed per trip. More uptime demands. More wear and tear. And a shrinking pool of skilled maintenance specialists. Efficient and livable cities made possible by reliable, intuitive and connected equipment is no longer a vision, it’s a mandate.

In some areas, change is long overdue. Take elevators. A pivotal force behind urbanization since their commercial introduction 200 years ago, reliability hasn’t been their strong suit. The industry annually experiences over 24 million breakdowns and 190 million hours of downtime.

The entire maintenance model is in need of repair. Elevator servicing today is largely reactive. Elevator components degrade towards failure, without intervention, resulting in sudden but inevitable breakdowns, disruption for passengers and heartache for building managers. Technicians are dispatched only after the fault is apparent. This approach does nothing for passenger convenience nor the elevator supplier’s bottom line. It also creates a “reactive Murphy’s Law situation” for elevator mechanics, says Chris Smith, Vice President for Service Innovation with leading elevator company, Otis. “[A mechanic will be] in the middle of a detailed maintenance routine at one building and get a service call [for a malfunctioning elevator elsewhere]. Now they have to leave, pack up their tools and drive—the most unproductive time you can have—to another building,” Smith told the IoT Podcast.

Scheduled servicing, in which maintenance is proactively carried out at fixed times to get ahead of equipment failures, is only marginally better. It incurs high costs due to premature replacement and disposal of working parts and the operational costs of closing perfectly-functioning elevators for servicing. With only 18 percent of equipment failing due to age, scheduling maintenance based on fixed timeframes doesn’t seem that smart.

Flawed maintenance strategies such as these translate to productivity losses of between five and 20 percent, according to Deloitte, to say nothing of the frustration it brings customers. “Customers tell us they want predictive, proactive and transparent [servicing],” says Otis’ Smith. “[They say] ‘I don’t want things to break, I want the elevators to be up and running’.”

Now, through a concept called predictive maintenance, the goal of radically extended uptime for critical equipment like elevators could be within reach. Powered by advancements in wireless sensor and network technologies, predictive maintenance lets service teams see the future state of their equipment and respond proactively. Here’s how it works: Wireless sensors placed on the equipment capture data about a spectrum of performance indicators. That data is locally analyzed by edge processors, and the critical information about the health of equipment is sent to technicians via the Cloud.

For example, for elevators, sensors might report on the distance an elevator has traveled. This could predict the elevator’s need for service based on usage since the last service. But the analysis can be even more granular. Consider that issues with doors account for 70-90 percent of elevator breakdowns (perhaps unsurprising, given doors contend with everything from the dirt and grime of city streets being deposited into their tracks to impatient office-workers forcibly holding them open). With connected tech, engineers can monitor this problematic mechanical part directly. The number of times a door has opened and closed, changes in power consumed to close doors, noise and vibration generated by the moving parts – all of these indicators can be monitored by wireless sensors and, when run through clever algorithms, can proactively reveal signs of deterioration.

The same approach could detect disrepair in other critical elevator parts including sheaves, bearings and sliding components that guide the cabin. This approach extends beyond elevators to other moving machinery, such as escalators and travelators (also known as moving sidewalks). The City of London is there already, using sensors to identify unusual vibration patterns in escalators that might indicate mechanical issues in advance of a fault. They’re also applying the principle to elevators, heating and cooling systems and communication networks.


For complex machinery with hundreds of parts—like elevators or escalators—wireless sensors can collect a large variety of data indicators such as heat, friction, noise, vibration and location. Transferring all this raw data to a service technician is cumbersome and impractical, not to mention costly in terms of bandwidth, says Lorenzo Amicucci, Business Development Manager at Nordic Semiconductor.

“A smarter approach is to perform edge processing, using machine learning to analyze the data locally and only send anomalies or patterns that reflect meaningful insights about the equipment,” he says.

Capabilities to do this exist in IoT devices such as Nordic’s nRF9160 SiP, which incorporates a powerful Arm Cortex M33 processor capable of sensor data acquisition, edge computing and basic AI data analysis. To get the data to remote technicians, the nRF9160 also supports the cellular IoT standards LTE-M and NB-IoT. These LPWAN technologies are ideal for predictive maintenance applications, because their low power consumption is critical for solutions using sensors that will run for years on battery power. The longer the batteries last, the easier the sensor maintenance becomes. In the future, low power wireless sensors might even be able to do without batteries at all by harvesting energy from the very vibrations they are monitoring.

While proprietary options exist, the value proposition of cellular IoT is compelling among LPWAN options. End users have immediate access to existing network infrastructure with global coverage. Mobile operators also continue to invest in cellular IoT networks, delivering solutions that are scalable and standardized. They’re also building ecosystems and open application platforms around these networks to foster partnerships which will be critical for development of IoT and predictive maintenance solutions. It all breeds confidence.

Moreover, in this connected age, malicious cyber actors have shown a willingness to disrupt cities by targeting critical infrastructure. Cellular is perhaps the most securecommunications technology around. Says McKinsey of these low power cellular networks: “Ultra-low latency and strong security will create the confidence to run ‘mission- critical’ applications that demand absolute reliability and responsiveness—even in vital infrastructure systems and in matters of life and death.”

But that’s not enough by itself; connectivity devices that are secure-by-design are also vital. Nordic’s nRF9160 SiP is one example; it makes use of Arm TrustZone’s additional layers of security to provide high levels of protection.

A final tipping point for cellular IoT LPWANs has been the maturing of the specific low-power cellular technologies, LTE-M and NB-IoT. Global standards recognition of LTE-M and NB-IoT is no small thing. This recognition will spur their continued evolution, not to mention uptake. Global ICT company Ericsson predicts LTE-M and NB-IoT will comprise about 45 percent of cellular connections by 2026.

Choosing between LTE-M and NB-IoT depends on the application and coverage, says Amicucci. “LTE-M offers higher bandwidth and is designed for more complex devices. It suits the elevator use as well as predictive maintenance of complex industrial assets. That said, NB- IoT could suit the elevator use case when it is located in a deep indoor location beyond LTE-M signals’ reach.”

Amicucci notes that for predictive maintenance, the nRF9160 SiP’s multimode support conveniently ensures industrial engineers can design solutions for both LTE-M and NB-IoT using the same component. He notes predictive maintenance will likely run on a dedicated specific comms module, while emergency calls services will be on different boards supported by, for example, LTE Cat1.


Predictive maintenance has long been heralded the IoT’s ‘killer app’. It’s easy to see why. Consulting firm McKinsey estimates predictive maintenance could reduce maintenance costs by 10-to-40 percent, equipment downtime by 50 percent and equipment capital investment by three to five percent by extending the useful life of machinery. The savings could translate to an economic impact of nearly $630 billion per year in 2025.

There are implications beyond the savings. Courtesy of predictive maintenance approaches, the green shoots of smarter, more livable cities may be starting to emerge.

In Japan, 34 million people ride the Yamanote Line around Tokyo each week. Trains leave every two minutes and run from early morning until late. Because breakdowns and ad hoc servicing won’t suffice, the East Japan Railway Company is now using sensors and IoT technology to forecast failures and efficiently schedule maintenance.

Elsewhere, flights in and out of our major cities will soon again be the norm. But can an industry decimated by the pandemic afford to resume paying annual unplanned maintenance costs of $20 billion annually? A piece of the aforementioned savings of predictive maintenance may be essential for this vital global industry to revive.

Cities, which often own and run airports, can benefit too. Düsseldorf Airport is using cellular IoT paired with heavy-duty sensors to prevent fuel supply bottlenecks that could cripple flight schedules. Each day more than 120 heavy fuel trucks, each carrying 30,000 liters of jet fuel, travel along a critical access road. Averting erosion and damage is important, but preventative maintenance approaches can be disruptive. Using Deutsche Telekom’s NB-IoT network to capture data on temperature, humidity and erosion from sensors in the road, maintenance crews now identify damage and schedule maintenance for the times when the trucks aren’t rolling.

These are just some of the possibilities. But think of any critical service in the modern city—sewers, water tanks, bridges, ATMs, even vending machines and automated parking gates—and a maintenance revolution driven by sensors and cellular networks beckons.

The timing is just right. “Using sensor technology like this is not new,” says Amicucci. “What is new now is the scale at which we can deploy these technologies, coming together with the emergence of low-power connectivity solutions to support our ambitions.”

Wireless sensor-based predictive maintenance might also spur the uptake of infrastructure that’s both more reliable and more environmentally sustainable. For example, Nordic’s nRF9160 SiP is now supporting smart power grids, using sensors to monitor for issues such as fires or a power surge and relaying this data via the LTE-M/NB-IoT modem.

Amicucci cites a further example: “Think about the emergence of electric vehicle charging stations – and you can see the role cellular IoT devices will play in safeguarding these and the health of other critical infrastructure in cities of the future,” he says.


Beyond practical benefits and financial savings, the use of cellular IoT for equipment monitoring may open up a new commercial dynamic between the industry’s suppliers and their customers.

Firstly, we might expect better relationships. The ability for suppliers to monitor equipment while in use creates a feedback loop for continuous improvement in equipment design and more tailored services. Customers get better products and suppliers can extract greater value from those products.

More profound is a shift in the very nature of the solution. With access to data on the use and performance of equipment, suppliers are sensing an opportunity to shift from selling equipment as a product to selling equipment ‘as-a-service’. Picture elevator companies selling a number of elevator trips rather than elevators themselves, or transit companies selling rail miles traveled rather than rail cars.

For customers, this new business model converts large up-front capital expenditures into a ‘pay-as-you-go’ operating expense. Further, payments can be contractually linked to the meeting of performance metrics such as uptime, availability and efficiency.

For suppliers, the as-a-service model delivers stickier relationships, by focusing on better customer experiences. This creates “a more intimate tie with customers that competitors would find difficult to disrupt,” says Mckinsey. Servicing is also more lucrative – in the elevator business, maintenance provides profit margins of up to 25 percent, compared with sales margins of five to 10 percent, according to The Wall Street Journal.

Shifting to these new models won’t be easy. While the benefits are clear, McKinsey observes that connectivity solutions and predictive maintenance will require: “Technical skills and an organization that is prepared to embrace data-driven decision making”.

Some say manufacturing and engineering companies may need to re-invent themselves as technology service providers. That may be overstating it. What does seem true for these solutions to flourish is strong collaboration across manufacturers, network operators, technology service providers, data analytics companies and others.

Ironically, there may be a silver lining to COVID-19. The pandemic shattered conventional molds for businesses, industries and economies. Those that survive have done so by being adaptable, resilient and determined, but perhaps more importantly, open to new ideas and collaborations.

This may be exactly the spirit required to finally realize the dream of smarter, reliable and sustainable cities.

This article is republished from Nordic Semiconductor’s Wireless Quarter with permission. www.nordicsemi.com/News/Wireless-Quarter