OTA + FreeRTOS Cellular is a power hog; How to use eDRX?

Partners & Sponsors AWS
1

Hi,

I’m using the OTA library in combination with the FreeRTOS cellular interface. I’m running it just as provided in the examples. The continuous cellular connection and the OTA client pings are a real power drain in my battery powered application.
The modem I’m using, the uBlox SARA-R4, features the power saving eDRX function. Can anyone here elaborate on a high level how this should be used in combination with the OTA library? Are there any examples?

2

It is not necessary to keep the connection open the whole time for the OTA library - you can connect periodically to see if there are OTA updates.

3

Ok, so what would be a good approach? Periodically alternate between an active and a low power state, by calling the following to enter low power:

prvSuspendOTA();
prvSocketDisconnect();
powerdowncellular();

And then do this to enter the active state again:

powerupcellular();
prvConnectToMQTTBroker();
prvResumeOTA();

Would that be a good approach?

4

Your approach sounds like it should work.

However before calling prvSocketDisconnect() you should also disconnect the MQTT connection. You can call MQTTAgent_Disconnect as a thread safe API to disconnect ongoing MQTT connection. Once MQTT Agent comes out of the command loop you can then disconnect the underlying socket connection.