LoRaWAN cannot support FOTA

This post was originally published on this site

LoRaWAN is unable to meet a key IoT network deployment requirement: bi-directional communication to upgrade firmware-over-the-air and update security patches to end-devices that have already been deployed in the field. To not be deceived by “demonstrations” of FOTA using LoRaWAN. It is indeed possible but not reasonable in a real world. What I mean: it is possible for a base station to do downlink to a single end device but in an actual REAL deployment there could be hundreds if not thousands of end devices….

Let’s first take a look at the three reasons why LoRaWAN is unable to support Firmware-Over-The-Air (FOTA) for a real IoT deployment.

1. With very stringent downlink limitations, LoRaWAN would take an unreasonably long time to update the firmware for a single end device. There are a few elements to take into consideration including the distance of gateway to end device and spreading factor utilised but It could potentially take weeks to send a 200K update to ONE end-device given 20 bytes on a 5-minute polling.

2. LoRaWAN gateway transmissions are uncoordinated. This means if a gateway attempts firmware downlink transmission, it will not be able to listen and receive messages from the rest of the end devices in the network. When you have thousands of end devices deployed, the end-devices won’t know the gateway is conducting a firmware upgrade and all messages being sent will be lost.

3. LoRaWAN gateways are duty cycle limited. LoRaWAN gateways can only transmit 1% of the time (ETSI), and will need all of the downlink resource for acknowledgements and MAC control messages. Very, very little would be left over for FOTA multicast. In the US, the 1% duty cycle limit does not apply so the network basically stops functioning to facilitate uplink.

Weightless-P is a narrowband LPWAN technology which looks like it can support FOTA and true bi-directional communication. Duty cycle limitations do not apply as Weightless-P utilises spectrally efficient narrowband operation and frequency hopping.

There have been so many early adopters who have rushed into deploying LoRa gateways without taking into consideration the major drawback of LoRa’s inability to support firmware-over-the-air.

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