RE: Using PSM with HTTPS Post every minute

Charlie — Mon, 04 Sep 2023 09:40:12 GMT

Hi,

The following two references may help you decide the proper technologies that can be used for your application.

Power saving techniques – Nordic Developer Academy (nordicsemi.com)

nWP044 - Best practices for cellular IoT development

Best regards,

Charlie

RE: Using PSM with HTTPS Post every minute

Achim Kraus — Sat, 02 Sep 2023 17:36:56 GMT

If you really want to send something every minute (60 seconds), PSM may not be the right feature for you. For short quite times eDRX may be a better choice. I would check, if that is available at your network provider.

If you use PSM, the phase your modem will use are:

- RRC connected while exchanging data. That includes also TCP internal ip-messages.

- RRC connected for the networks RRC Active timer (depends on the network, maybe 10s). Or requires RAI. For TCP only AS-RAI may have a chance, but for now I haven't seen, that someone reports success with that.

- RRC idle for the PSM active timer.

I would guess, that you need about 8s for the data exchange (about 80mA), 10s RRC active timer (about 40mA). I don't see, what you request as "PSM active timer". If you add all these times, you will get the PSM time. The saving is then the difference between RRC idle (1mA) and PSM (3µA) for that time. Maybe that calculation already shows, that your savings will be no game changer.

(Just to mention: those who want to run from battery over months usually use UDP, and usually send data much less frequent, e.g. every h and only on events in time.)