Blog post – Paris, France – February 1st, 2022
Thanks to our ThingPark® IoT platform, developers can set up a LoRaWAN firmware update over-the-air (FUOTA) campaign using an STM32 LoRaWAN® gateway (STM32F7) and client (STM32WL) in under 10 minutes only. A new video walks users through the process and uses ST development boards to lower the barrier to entry. The content is also highly symbolic as it features Actility’s new interfaces that aim to reduce friction.
This an original blog by STMicroelectronics, you can view it here.
Follow the Getting Started video to setup the STM32WL, then watch the Actility FUOTA Demo to quickly understand how launch the FUOTA campaign on ThingPark:
Sub-Gigahertz networks are increasingly popular but firmware updates over the air remain challenging to set up due to their complexity. Without FUOTA, companies need an army on the ground, physically attending to each device to perform maintenance operations, which is costly and impractical. However, securely pushing small packets to update a device safely demands mastery of multiple communication protocols and low-level coding. Actility thus offers back-end and client infrastructures to shift this burden away from developers. Moreover, as an ST Authorized Partner since October 2018, Actility offers solutions compatible with ST’s LoRaWAN stack.
Simply implementing a firmware update over-the-air mechanism isn’t always enough. Many are looking for granularity. For instance, some would need to update a subset of a fleet because of constraints or feature requests. However, few solutions allow for such finesse. The problem is that such a system usually suffers from packet losses or out-of-order deliveries. Hence, Actility developed its ThingPark FUOTA multicast server to solve these challenges. A unicast protocol uses one server to talk to one device. On the other hand, a broadcast system uses a server to talk to all devices at once. RMC can target a subset of devices and doesn’t suffer from the usual pitfalls.
Actility’s ThingPark RMC server features three critical modules: fragmentation, clock sync, and remote multicast setup. The first one breaks down the update into chunks compatible with the traditional LoRaWAN payload (maximum 255 bytes). The solution also includes a forward error correction system and redundant packets to protect against losses or corruption. Engineers often overlook this aspect, but properly fragmenting an update to send it over the air is complex and a vital part of the process.
The clock synchronization helps switch all end devices about to receive an update from Class A to Class C temporarily at the beginning of the multicast session to coordinate packet reception. Finally, the remote multicast setup programs the FUOTA campaign. Developers can remotely setup the multicast identity and distribution window onto end devices to change the subset about to receive the updates if necessary.
Processing a FUOTA is also a sensitive mechanism on the client device. The update cannot brick the system or compromise its security. Hence, to optimize the update process, our developers created an update agent that acts as an intermediary between Actility’s modules and our Secure Boot and Secure Firmware Update (SBSFU) stack. Once the software processes the packages from the RMC server, the update agent ensures that the SBSFU system on the microcontroller writes on the correct memory space before the SBSFU module securely updates the firmware. In a nutshell, by working with Actility, we created a complex update agent that ensures the device’s security and integrity.
The beauty of this whole solution is that it exists within the STM32Cube ecosystem. The demonstration in the video runs on an STM32WL, but it is possible to use another device. Engineers can also utilize our existing LoRaWAN stack (I-CUBE-LRWAN) to start working on their application, and our tutorials show how to set up a LoRa node in 10 minutes. ST’s  B-L072Z-LRWAN1 and I-NUCLEO-LRWAN1 boards will help them prepare for the upcoming public release of our FUOTA solution in collaboration with us.
LoRa Alliance® and LoRaWAN® are marks used under license from the LoRa Alliance.
Learn more about the LoRaWAN technology by downloading the Actility “What is LoRaWAN” white paper