The lightbulb moment for future smart cities


Sooner rather than later, smart cities will provide urban populations with a healthier, safer and greener lifestyle. But when and how will this dream be attainable?

By Alf Helge Omre, Business Development Manager – Smart Lighting, Nordic Semiconductor 

While it’s impossible to predict a precise timeline, because the technology already exists to make the promise of smart cities a reality we shouldn’t have to wait too long. But challenges remain. 

To fulfil their potential, smart cities will need to piggyback street-lighting infrastructure. As a platform capable of uniting multiple applications gathering information about city activity and environmental conditions, street lighting offers the best foundation for rapidly rolling-out smart technology. 

How exactly will this happen? The answer lies in converting existing street lights to power-efficient LED bulbs, then adding wireless connectivity and supporting devices such as sensors for air quality analysis and congestion management. Once rolled-out, street light-based smart infrastructure could support various use cases including traffic control and flow, noise and air pollution, pedestrian security and even things like gunshot detection. 

The difficult journey to smart cities

By 2050, seven out of ten people are expected to live in a city. If those cities are smart, the new urban populations will benefit from a higher quality of life. However, the smart city concept has stalled by roadblocks such as the prohibitive cost of new infrastructure. Smart cities are problematic to cost, fund and build. For example, calculating the impact of lower pollution on health services is a far from a simple task - making it difficult to justify air quality monitoring infrastructure. These challenges combine to ensure the concept of integrated city-wide digital operations has remained largely out of reach. 

But change is afoot. The transition from sodium-vapour lights to LEDs is encouraging a rethink of smart-lighting infrastructure. Around 90 percent of the planet’s 300 million street lights will use LEDs by 2027, according to research by smart infrastructure analyst Northeast Group. Lighting and sensor makers suggest the new technology will lead to a 50-70 percent reduction in the management and maintenance costs associated with street-lighting infrastructure. Around half of those savings will be achieved just by switching to LED, with the rest coming from connecting and controlling the luminaires, and feedback of useful intelligence about their working status. The promise of significant cost savings justifies the expense of upgrades and at the same time provides an opportunity to fit out the poles with wireless sensors.

From such a foundation, cities can become truly smart. Some are already well on the way; San Diego in the U.S. and Copenhagen in Denmark are among an increasing number of cities across the globe with smart street-lighting projects leveraging an array of sensors in modular hardware units affixed to light poles. Out of around 200 cities tracked by analyst firm, Guidehouse Insights, to gauge the pace of urban change, a quarter are rolling out smart lighting initiatives. Meanwhile over two-thirds of new street-light installations will be tied in with central management platforms as early as 2021, says ABI Research, in order to integrate data from multiple smart city sensors. 

Dual-mode IoT connectivity

Smart city wireless connectivity will team short-range wireless networks with Low Power Wide Area Networks (LPWANs) to gather sensor data and forward it to the Cloud. Short-range wireless—such as Bluetooth LE, interoperable with almost all smartphones on the market, or Zigbee—offers low cost, low power consumption, mesh networkable foundation technology for ‘Lighting as-a-Platform’ (LaaP). (LaaP is the use of light fixtures as the foundation for an array of connected sensors.) Short-range wireless networks have a range of just a few hundred meters and are not interoperable with Internet Protocol (IP). LPWANs provide the kilometre-plus range and IP interoperability needed to forward short-range wireless network data to the Cloud.

Of the various LPWAN alternatives, only cellular IoT (NB-IoT/LTE-M) can leverage the mature 4G networks widespread through many cities around the world. NB-IoT and LTE-M support the infrequent and low-throughput transmissions typical of IoT applications, making it possible to connect several tens of thousands of devices to a single base station. And as cell towers typically host several base stations, deployment density is multiplied and massive scale promoted.

The smart city will demand many different applications each making various demands in terms of coverage, throughput and security. By employing complementary wireless technologies it is possible to satisfy all these demands. Further, by embedding short-range wireless and cellular IoT in the same hardware, LaaP developers can bring tighter technological integration and lower acquisition costs to their design – characteristics which are prime considerations for smart cities. 

The market is already heading in this direction. Low power wireless solutions vendor, Nordic Semiconductor, for example, has already combined short-range wireless and cellular IoT connectivity in hardware and software, at the developer level, for engineers to experiment with the technologies in test applications. Certain Nordic products are ideally suited to smart city applications. For example, Nordic’s nRF52840 System-on-Chip (SoC) supports Bluetooth LE, Bluetooth mesh and Zigbee, as well as Thread and proprietary 2.4 GHz protocols, while the company’s cellular-based nRF9160 SiP offers both LTE-M and NB-IoT. The Nordic Thingy:91 prototyping platform combines the nRF52840 SoC and nRF9160 SiP on the same PCB, allowing developers to immediately begin prototyping dual-technology smart city and LaaP solutions. 

Powered by low power wireless technology, street lights are set to support the smart cities of the not-too-distant future. It could well be that using smart street-lighting infrastructure as a platform for smart cities will be lightbulb moment for the planet.

Street light-based smart infrastructure could support various use cases including traffic control and flow, noise and air pollution, and even things like gunshot detection