Hi, I am currently developing a solution to connect a module using BG96 to AWS IOT Core using MQTT over LTE-M. The key criteria of our implementation is that it has to consume as little power as possible, with the module sending an update through MQTT every 10 minutes or so.
We are currently exploring using PSM of BG96 to achieve this but in practice, we have not observe any significant decrease in power consumption when using PSM on our module and it does not wake up upon expiry. In addition, as there is no persistence of the MQTT session, we have to re-establish and authenticate with AWS upon waking up. Is there any way for us to minimize the power consumption further?
I wouldn’t reccomend MQTT for power-constrained devices, the whole handshake consumes a lot of data/power and as you experienced, state is lost between connections.
I’d use CoAP instead, but you’d need a service in the middle for it.
Thank you for the response! Currently exploring CoAP for our devices but the main issue is that our BG96 firmware doesn’t support CoAP natively, but they do have LWM2M enabled. Do you have any experience working with that?
I have sent you the relevant guidance document, you can refer to it. In addition, regarding psm, can you send the ATlog of your configuration execution? I will check if there is any unreasonable place. It is supposed that the power consumption will be significantly reduced when entering PSM.
I don’t have direct experience with LWM2M but it seems suitable to your needs, and it also seems to leverage COAP.