Wi-SUN vs. Wi-Fi

An important enabler of smart cities and the smart energy grid is the Wi-SUN Alliance. Perhaps that is why several organizations and government agencies have recently committed to the adoption of the wireless interoperability standard for smart cities, smart utilities, and Internet of Things (IoT) applications. Both Arm and Silicon Labs, two major global semiconductor companies, are now part of the Wi-SUN board of directors.

Still, many engineers outside of the smart energy grid market may not be familiar with the wireless standard. Why this growth in the usage of Wi-SUN protocols? How does Wi-SUN wireless differ from Wi-Fi and other standards? To answer these and other questions, Design News reached out to Phil Beecher, president, and CEO of the Wi-SUN Alliance. 

Design News: How do you explain the recent growth of Wi-SUN related wireless technologies?

Beecher: Wi-SUN Field Area Network Technology has been deployed in the Utility Industry for a long time (more than 10 years).  The alliance has brought about the convergence of best of breed technology from multiple vendors, providing a reliable, resilient, and secure communications architecture suitable for all large scale IoT applications, going beyond just utilities to also address the needs for Smart City automation.

Design News: How does Wi-SUN compare to existing wireless protocols? What advantages does it afford to designers?

Beecher: With cellular and LPWA architectures, devices communicate directly with a base station. If there is no base station in range, a device cannot communicate. Wi-SUN FAN is different: it uses a wireless mesh architecture based on open standards from IEEE, IETF (the internet engineering task force), and other organizations. A mesh network brings much more flexibility to in-device communication.  If a device cannot talk directly to a router, messages can hop through neighboring devices.  This provides excellent connectivity, particularly important in dense urban environments where urban canyons cause connection problems.  If there are partial network failures (for example during power cuts or as a result of natural disaster, earthquake, hurricanes, etc.) then the network will automatically reconfigure to ensure that a maximum number of devices can still communicate.   Mesh networks are not new, it is how the Internet is built to provide great resilience, but Wi-SUN Alliance has defined how to use the relevant open standards in a way to enable multi-vendor secure, resilient, interoperable solutions for large outdoor IoT networks. 

Design News: You mentioned a Wi-SUN supported lighting application in the City of London. How did it go?

Beecher: The city of London is a challenging environment for communications, with a mix of modern, tall buildings and old, narrow streets.  The City of London looked at their options and decided that Wireless Mesh communications would provide the best coverage and flexibility for the future.  Wi-SUN FAN provides a communications infrastructure, not only for the initial streetlighting installation but enables the city to install other devices, e.g. pollution monitoring, parking management, from a choice of vendors, which will integrate into the same network.  For the initial installation, great attention has been given to the location, style, brightness, and color of the lighting, and all this can be controlled dynamically by the city council. LED lighting reduces operating costs through reduced energy use and reduced maintenance. Automated fault detection ensures that lighting can be maintained.  The City of London feels like a safe place to walk, increasing foot traffic and enabling growth in restaurants and other retail outlets.

Design News: What next for Wi-SUN, i.e., what does the future roadmap look like?

Beecher: We are increasing the communications speed to support more demanding applications for utility networks, such as distributed control of the grid, and integration of renewable energy generation and storage. We are also working on reduced power consumption to provide even longer battery life for devices that do not have mains power available, such as water and gas meters and low-cost sensors.  Additionally, our member companies are working on higher integration chips, which will reduce device costs and further improve energy use and battery life.  These developments are all evolution of the technology and will integrate into existing networks.

John Blyler is a Design News senior editor, covering the electronics and advanced manufacturing spaces. With a BS in Engineering Physics and an MS in Electrical Engineering, he has years of hardware-software-network systems experience as an editor and engineer within the advanced manufacturing, IoT and semiconductor industries. John has co-authored books related to system engineering and electronics for IEEE, Wiley, and Elsevier.