Secure Sub-GHz SoC FG25 Ideal for Wi-SUN Smart City Applications

SILICON LABS has a long history of innovation around low-power wireless area networks (LPWAN). The technology is beginning to develop on a worldwide scale, and we’re already on our fourth generation of sub-Gigahertz (GHz) radios, as we helped create some of the first “smart meters” for utility companies.

Now, the needs of utility companies and others that operate connected city operations, such as traffic lights, are looking to get more from their devices. When they first launched, these connected devices were about better monitoring. For example, a smart electric meter on a single-family residential home would tell the utility company how much electricity the household used each month for billing purposes, but not much else.

Like many other industries that are tapping into the IoT, utilities are looking to get more data back from the device itself that can inform how it can better streamline and correct inefficiencies, identify whether maintenance is needed and where it’s required, and predict when the utility network may be under heavy use and therefore need corrective measures to prevent disruption. In the past, utility companies could only predict the quantity of electricity used. With these new advancements, they can now accurately determine when the electricity was used, the rate at which it was being used, and the geographic areas that saw the most demand.

This enables companies to provide rush-hour energy rewards on intelligent thermostats. By opting in for incentives, customers can allow the utility company to control their thermostat while ensuring they stay at a comfortable temperature, and thus more effectively spread the energy load across the grid. This is just one example, and with other use cases including streetlights, asset tracking, environmental monitoring, structural monitoring, and more, the number of potential connections can number in the hundreds of thousands, and in the largest of cities, in the millions. The sheer number of these likely devices needs a very-large, standards-based network and open source to support multiple devices.

Wi-SUN Turns Cities into Stars
This is where the Wireless Smart Ubiquitous Network, or Wi-SUN, comes in. The Wi-SUN protocol delivers a large-scale, standards-based mesh networking solution in long-range sub-GHz frequency bands that is impossible with existing mesh networking IoT standards such as Zigbee, Thread, Z-Wave, and Bluetooth mesh. Silicon Labs was an early adopter of Wi-SUN technology and is taking it one step further with the announcement of our new FG25 SoC and the EFF01 RF front end module.

The FG25 sub-GHz SoC can operate on a coin-cell battery for ten years, making it an excellent fit for Wi-SUN’s ability to form both mesh and star network topologies, thereby optimizing for low power and performance for the network itself and the devices on it. A star topology is when there is a central hub with many different connections coming out from it. Another way to think of it is like a wheel and spokes. That hub is a router, and Silicon Labs is also announcing its Field Area Network (FAN) 1.1 Border Router reference design, which is available for download.

Using a Wi-SUN FAN 1.1 Border Router, users could place their hub on a wired device, like a streetlight or something similar, with little to no power restrictions. That streetlight then becomes the hub to support thousands of other devices that are themselves a mix of line-powered and battery-powered. Those battery-powered devices can then extend the reach of city services. This would allow highway operators to easily monitor the temperature of asphalt in remote stretches of highways or the movement of a distant suspension bridge for any anomalies. By increasing the number of different factors they can monitor and measure, and expanding the volume and types of data they can gather from the device, Wi-SUN and the FG25 SoC and EFF01 FEM can help drive efficiencies, lower cost, improve safety, and more.