Is the IoT the key to the smart city? Byron BeMiller, director of Smart Building Applications, Wireless and Sensing Products Group at Semtech Corporation, explores how wireless technology is making cities not only smarter, but more efficient.

The Internet of Things (IoT) is becoming the backbone of a smart city. Already, we are seeing buildings connected via scalable networks and ‘intelligent’ road management systems providing the data which smart cities depend on. Of course, once a standalone city is fully connected, it is no major step for it to link with another smart city and another until an entire national – and ultimately international – network is created where devices communicate with each other millions of times a second and data is passed back and forth along extensive long range networks.

Armed with the technology that the IoT delivers, building facilities managers are already able to monitor and control a building’s entire central systems, including those that provide heating, cooling, fire detection, room management, lift management, equipment failure prediction, and more. Among the many benefits of having all of this valuable data to hand in real-time, as well as the ability to act on it, are substantial time savings, labour savings and reduced operational costs.

Instead of carrying out scheduled maintenance programmes at set times and checking everything even though it is working at optimum efficiency, building service managers will be alerted via predictive maintenance if anything is likely to require their attention. Since IoT is based around sensors that collect and feed data every second of every day, facilities managers can be made aware of such issues as air quality, smoke detection and even changes in temperature which may be an indication that something is not right in the building. Apart from equipment not working as it should, alerts can include whether there is a window or door open that should be closed, if there is a leakage of any kind in the building, if there are any unexpected structural vibrations, or even if an unauthorised person is on the premises.

Of course, intelligent building management is not only concerned with overseeing utilities and security systems or operating refuse and waste systems. The efficiency of a building, including where heating, air conditioning or other services would best be targeted, can often be dictated by room usage, office layout and even the location and timing of meetings. Instead of having a reasonable idea of how many people are in a building, where they are and what they are doing, it is now possible to have exact figures and know precise locations.

While some sensors and equipment can be hardwired, it is not practical to install cabling and wiring throughout an entire building in order to connect hundreds or even thousands of sensors (not to mention the cost of powering every sensor). Nor is it sensible for different buildings and various other aspects of a smart city to be connected by cable. There only has to be one broken link to bring down an entire system and finding it among miles of cabling would be nearly impossible. Also, scalability in terms of adding extra sensors is costly and far from straightforward.

The solution, then, is wireless technology. Everyone is used to making connections via cellular networks or Wi-Fi or Bluetooth, but none of these can achieve the distances or provide the degree of security required when connecting buildings and smart cities through IoT. Air quality in a hospital, for example, cannot be allowed to deteriorate or traffic management systems cease to operate simply because there has been a drop in the network signal, or it struggles to pass reliably through a concrete wall.

So far, 5G technology has been found to be suitable for such uses as internal and external vehicle communications, remote healthcare and driverless cars, but no cellular technology on the market, not even 5G, delivers the level of reliability required for full IoT implementation. Another option, narrowband IoT (NB-IoT) will offer the ability to be used across existing mobile networks and to operate in a licensed spectrum, meaning industry support will be widespread when the technology is available.

However, leading smart cities today are taking advantage of low-power wide area networks (LPWAN) enabling IoT devices and smart networks to operate at optimal efficiency on a local, national or global basis. In addition, a long-range wireless radio frequency technology, which enables devices to connect with low-power LPWANs, also ensures data security through end-to-end AES128 data encryption and mutual authentication.

This technology enables communication with sensors which operate at distances of up to 30 miles, have battery life of up to 10 years and can penetrate dense building materials. GPS-free geolocation technology means that no extra power source is required, open network technology means users can connect to their preferred network service provider, and since the technology operates in the unlicensed ISM band, spectrum costs are extremely low or zero.

In buildings and cities around the world, wireless connection to public and private LPWANs is becoming the technology of choice in IoT applications where data is collected and analysed via cloud-based or enterprise- based systems. Whether a local authority is wanting to save energy through smart street lighting, or a building facilities manager is looking to improve customer service, while saving time and unnecessary costs, LPWANs are recognised as the most efficient way of enabling sensors to communicate via gateways and cloud-based platforms. For example, LoRaWAN has been adopted in more than 100 countries, where it has connected roughly 90 million wireless sensors, actuators and tags.

Practical examples of how LPWAN technology has increased efficiency and cut costs include a local authority’s smart waste management system that slashed costs by 83% and boosted recycling by nearly 50%. In another example, the technology enabled a city to increase the output of its solar power facilities to around 750,000 KW/h.

IoT is how the world’s buildings and cities of the future will connect and stay connected. To achieve the goal of making cities and buildings smarter and more efficient, scalable communications will need to rely on wireless technologies that operate over long distances, keeping deployment, as well as operational costs to a minimum.