Seeking Recommendations for LTE Network Timeout Configuration

RE: Seeking Recommendations for LTE Network Timeout Configuration

Hakon — Mon, 07 Jul 2025 11:56:41 GMT

[quote user="tareq_itx"]I am trying to understand what is the deference between the two attempts and why the current consumption in the second one is higher than in the first one? [/quote]

The reason you are seeing a higher current draw in the second graph is because in the second attempt the modem actually finds a signal. And when the modem receives a signal it will try to send out a connection request. Those are the 300 mA spikes you are seeing the second graph.This is also why you get

[23:19:10.506,195] <inf> modem_service: LTE_LC_EVT_CELL_UPDATE: MCC: 0, MNC: 0, TAC: 44934, RSSI: -140 dBm

in the log. That's from the received signal.

In the first attempt the modem does not detect any signal whatsoever, so it just keeps scanning with 40-50 mA RX output.

But -140 dB RSSI seems rather low, so that can be the reason why it is not able to connect. I think the CONEVAL command can be useful for determining the energy efficiency of your searches, and evaluating the signal conditions before trying to connect. This is something you should consider using in your application.

RE: Seeking Recommendations for LTE Network Timeout Configuration

tareq_itx — Mon, 07 Jul 2025 11:27:29 GMT

Hakon Thank you very much for your response, i will have a look at the periodic search config.

I still have questions regarding the current consumption during attempting to connect to the network (with 10 min timeout). Most of the time in case there is no network coverage i record the following pattern of the current consumption during the 10 min attempt. Can you explain what the modem exactly do in these 10 min? Does it continuously scan/search for a network, does it use different band for the search ... ?

Logs of this failed attempt:

[00:10:01.715,026] <dbg> modem_service: modem_service_start_modem: Next connection attempt in 1 seconds
[00:10:02.715,118] <dbg> modem_service: modem_service_start_modem: Reattempting to establish LTE connection ...
[00:10:02.725,982] <inf> modem_service: LTE_LC_EVT_MODEM_SLEEP_ENTER: FLIGHT_MODE (-1 ms)
[00:10:02.756,805] <inf> modem_service: LTE_LC_EVT_MODEM_SLEEP_EXIT
[00:13:25.742,156] <inf> modem_service: LTE_LC_EVT_NW_REG_STATUS: UNKNOWN
[00:20:02.856,781] <inf> lte_lc: Network connection attempt timed out
[00:20:02.875,610] <inf> modem_service: LTE_LC_EVT_NW_REG_STATUS: NOT_REGISTERED
[00:20:02.901,794] <wrn> modem_service: LTE connection attempt number 1 failed!

Another 10 minutes failed attempt but with slightly different pattern and higher current consumption was recorded

The logs from this attempt are also slightly different from the first one

[11:11:16.849,822] <dbg> modem_service: modem_service_start_modem: Next connection attempt in 43200 seconds
[23:11:16.849,945] <dbg> modem_service: modem_service_start_modem: Reattempting to establish LTE connection ...
[23:11:16.860,900] <inf> modem_service: LTE_LC_EVT_MODEM_SLEEP_ENTER: FLIGHT_MODE (-1 ms)
[23:11:16.891,784] <inf> modem_service: LTE_LC_EVT_MODEM_SLEEP_EXIT
[23:11:18.673,736] <inf> modem_service: LTE_LC_EVT_NW_REG_STATUS: SEARCHING
[23:14:26.226,898] <inf> modem_service: LTE_LC_EVT_NW_REG_STATUS: UNKNOWN
[23:19:10.506,134] <inf> modem_service: LTE_LC_EVT_NW_REG_STATUS: SEARCHING
[23:19:10.506,195] <inf> modem_service: LTE_LC_EVT_CELL_UPDATE: MCC: 0, MNC: 0, TAC: 44934, RSSI: -140 dBm
[23:19:10.506,256] <inf> modem_service: LTE_LC_EVT_LTE_MODE_UPDATE: NB-IoT
[23:21:16.991,760] <inf> lte_lc: Network connection attempt timed out
[23:21:30.899,230] <inf> modem_service: LTE_LC_EVT_NW_REG_STATUS: NOT_REGISTERED
[23:21:30.899,291] <inf> modem_service: LTE_LC_EVT_CELL_UPDATE: MCC: 0, MNC: 0, TAC: 4294967295, RSSI: -140 dBm
[23:21:30.899,353] <inf> modem_service: LTE_LC_EVT_LTE_MODE_UPDATE: NONE
[23:21:30.909,332] <wrn> modem_service: LTE connection attempt number 9 failed!

I am trying to understand what is the deference between the two attempts and why the current consumption in the second one is higher than in the first one?
Does the modem consume more power during attempting to attach to a network than scanning for a network?
If that is the case then the reason might be that in the second attempt the modem found a network at the end of the 10 min interval and tired to attach to it but it failed to do that within the 10 min interval.
Could that be the reason for the higher consumption at the end of the interval ?

RE: Seeking Recommendations for LTE Network Timeout Configuration

Hakon — Mon, 07 Jul 2025 10:58:04 GMT

Hello,

[quote user=""]Do you have any recommendations for an appropriate value for CONFIG_LTE_NETWORK_TIMEOUT?[/quote]

It is quite hard to suggest anything concrete here, unless I know exactly what sort of conditions you expect to use the modem. I believe the default value should be left untouched, as it is optimized to work for the general case. And as it seems you are not targeting a particular type of area, then I think the default value should be good.

Also, consider using periodic search configuration. That can further improve power consumption in network searches. You can look at Øyvinds response here.