When does the nrf9160 modem decide to perform an LTE network search?

[EDLT]

Hello,

I'd like some clarification on the nrf9160 modem behavior. What is the criteria for the modem to perform a network search?

I've used the default search pattern for ultra-low power profile and subscribe to modem events. When I put the device into a shielded enclosure and it disconnects, I don't see any subsequent search events. However, when I remove the device from the enclosure, I am connected again to the network quickly.

What is the modem doing when it is disconnected? I would expect to get a number of search events within the first few minutes of not being connected. 

Apologies in advance if I'm missing something clearly stated in the 3GPP spec that the describes what is actually going on there.

Thanks!

P.S. Using MF 1.3.1 with NRF Connect 1.9.1

[Michal]

Hello,

How are you checking for the connection events? Have you done a modem trace?

Best regards,

Michal

[EDLT]

Hi Michal,

We're doing the standard async connection event handling. I'm not sure the modem trace is relevant to my inquiry.

I'm really asking for an understanding of the default modem behavior when doing network searches.

[EDLT]

I've spent some time with the power analyzer which was informative. I've come to the conclusion based on power usage that searches are being performed as expected.

However, we are only notified of the search's completion after the first search of its kind (light or full). This seems like a bug in the lte_lc or modem event reporting...not sure which. This is what was confusing me and caused the initial inquiry.

Do you guys see the same behavior of only the first modem search event is report to the LTE even handler?

[Achim Kraus]

In my experience, these "Search Events" are good hints, but not that complete . E.g. HPPLMN searchs are not covered, at least not with mfw 1.3.2 .  

[gjoasen]

I'm also seeing this, only get notified of the first search.  I'm on modem fw 1.3.4 and nrf connect v 2.2.0. 

Michal, is this a known bug and something that might be resolved in later releases?

[Michal]

I will ask the experts about it and get back to you.

Best regards,

Michal