Wireless technologies and IoT applications have made the quest to build smarter cities very achievable, instead of a distant, lofty vision.

Across the globe, smart city technology spending is expected to boom to $327bn by 2025, up from $96 billion in 2019. More cities are digitising utilities, transportation, traffic and waste networks to improve security, infrastructure, energy efficiency and sustainability – but new and different challenges come with this transformation.

Even though these critical networks can become connected, cities are ironically facing a massive disconnect: the smart city applications on these networks are relatively isolated and often can’t connect that well with each other because networks are oftentimes proprietary and therefore, non-interoperable. Imagine, how can smart city sensors on streetlights collecting data transmit it back to a traffic monitoring application effectively if the sensors and applications aren’t integrated on the same network?

Proprietary networks can be complex, fragmented and limiting, in terms of adding new devices easily from a wide variety of ecosystems. They are also more susceptible to cybersecurity breaches – a growing, global concern as seen with ransomware attacks to systems in cities such as Las Vegas and New Orleans.

Scaling Obstacles to Connect Everything

To modernize the grid infrastructure and enable innovation across industries, cities need flexible wireless standards to deploy IoT applications securely and at scale. Enter: Wi-SUN, one of the world’s first public protocols for smart city and smart utility applications. Launched in 2011, Wi-SUN, which stands for Wireless Smart Ubiquitous Networks, is an IPv6-based mesh technology designed for large-scale IoT wireless communication networks in a wide range of applications covering both line-powered and battery-powered nodes. Market leaders such as Landis + Gyr, Cisco, Toshiba, Renesas, Itron and more also join Silicon Labs as members of the Wi-SUN Alliance.

Wi-SUN is opening doors as a standard, interoperable network, enabling a self-forming mesh with thousands of end nodes connecting dynamically with each other.

The protocol features low latency, higher data throughput benefits, further catering to complex device requirements in low power, long range devices such as streetlights or battery-operated gas and water meters. Streetlights, for example, are becoming increasingly digitized with sensor nodes that can monitor environmental air quality, parking, waste management, manhole cover detection and other uses. Analysing real-time data from these sensors can help inform solutions to reduce energy consumption, reduce greenhouse gas emissions and provide higher quality civic services to more people across the entire city landscape.

The mesh architecture offers significant latency gains as opposed to a typical star wireless network centered around a central server hub. Wi-SUN’s IoT network offers 0.02 -1 second latency, compared to other low-power wide-area networks such as LoRaWAN, offering 1 – 16 seconds and NB-IoT offering 2 – 10 seconds. Wi-SUN is currently governed by the FAN 1.0 specification, with the next version FAN 1.1 expected to be ratified later this year. Wi-SUN’s FAN 1.1 specification delivers enhancements such as OFDM support allowing data rates up to 2.4 Mbps to support demanding low-latency applications, leaf-node support for longer battery life of up to 20 years, as well as mode-switching that allows for dynamic data rate negotiation.

Wi-SUN enables utility providers to serve all their metering needs on one network. FAN 1.1 enables use of the same network for line-powered electric meter devices as well as battery operated water and gas meters. Essentially, having all applications interoperable on one Wi-SUN network creates an opportunity to scale existing infrastructure relatively quickly without modification, which can be time consuming and expensive, or limiting if connectivity is required outside of one network. One can think of Wi-SUN FAN as a true Internet-like infrastructure optimized for IoT devices. Recently, the Wi-SUN FAN specification was adopted by the IEEE Standards Association, further demonstrating the network’s capability to be accepted globally for open standards communications and cybersecurity standards.

Securing Critical City Infrastructure

Mesh networks like Wi-SUN with multiple connections provide stronger protection and reliability. If one node is down or compromised due to an attack or an extreme weather event like a hurricane or ice storm, the mesh network is self-healing and can reroute data to an unaffected connection. Massive loads of data within applications will always attract adversaries; therefore, expanding smart city means ramping up protection in critical infrastructure against vulnerabilities.

Based on IEEE 802.15.4g/e standards, Wi-SUN is also attractive from a security lens because the network devices authenticate all the way back to the cloud provider through a certificate chain that is cryptographically linked. Wi-SUN’s certificate chain provides the secure identity that is required for continuous authentication to meet the Zero Trust security architecture – which is beginning to dominate the industry, as seen with the Biden administration’s executive order on improving cybersecurity.

Strong certificate-based identities that authenticate to a cloud service have been common in the utility space for many years. However, this advanced continuous device authentication method being integrated into a wireless protocol like Wi-SUN is new, transformational and necessary as smart city devices will represent as enticing publicly accessible targets for cyber criminals looking to exploit public infrastructure for ransom payments.

As pressure mounts to address aging infrastructure that is increasingly vulnerable to cyberattacks and warming climate conditions, Wi-SUN’s scalable, resilient and secure wireless technologies serve as an accessible solution to create a more sustainable future.

Author details: Soumya Shyamasundar is a Product Manager with the wireless IoT group responsible for Wi-SUN markets at Silicon Labs.