RE: Roaming implications on power usage

Thomas — Tue, 14 Jun 2022 08:10:53 GMT

Thanks Håkon, this was very helpful.

RE: Roaming implications on power usage

Håkon Alseth — Tue, 14 Jun 2022 07:32:52 GMT

Hi,

[quote user=""]My question is, how frequently does the nrf9160 do another full band scan in search of a home network, if ever? Does it only do another full band scan if the roaming network it was connecting to is lost?[/quote]

The period of the higher priority PLMN search is read out from the SIM card. The minimum is 2 hours, as per 3gpp 23.122 chapter 4.4.3.3.1.

This is a search that can occur while you're connected to a roaming network, but only when the link is idle.

However, the same chapter also mentions:

periodic attempts may be postponed while the MS is in power saving mode (PSM) (see 3GPP TS 23.682 [27A]).

Meaning that you will not see such a search while in PSM.

[quote user=""]My question is, how frequently does the nrf9160 do another full band scan in search of a home network, if ever?[/quote]

This depends on what values are programmed into your SIM card. Min. 2 hours, but only if the link is idle (for instance in eDRX/RRC idle etc)

[quote user=""]Does it only do another full band scan if the roaming network it was connecting to is lost?[/quote]

It can do this if the lte link is in an idle mode (ie. not currently in PSM), but only in the intervals that are read out from the SIM.

This also depends on your power profile settings, for instance what's set in this AT command:

https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/mob_termination_ctrl_status/xdataprfl_set.html?cp=2_1_4_13_0

Kind regards,

Håkon