nRF9160-DK - sometimes busy for 1 minute before entering PSM

[Achim Kraus]

Using the nRF9160-DK together with the Power Profiler Kit 2, I observe sometimes a longer period (1 minute) of a 50mA consumption before entering PSM mode.

Is there a explanation for that? Could that behavior be "forecasted", or better disabled?

[Hakon]

I had the modem team look at the modem log. Here's the response;

The log shows that there is Higher Priority PLMN (HPPLMN) search initiated after one of the RRC connection releases and that caused the delay. The search has been specified by 3GPP and must be done while not in home network. The search is controlled by a timer and if the timer expires while in PSM, then the HPPLMN search must be done when waking up from PSM. But in this log the timer expired already before entering PSM which is why the search was initiated and completed before entering PSM.

[Achim Kraus]

Thanks for analyzing the log.

Is that HPPLMN search timer configurable? Or which time is used for that?