AT%CONEVAL response time

RE: AT%CONEVAL response time

optical — Mon, 06 Nov 2023 05:42:14 GMT

Would be pretty helpful if the nordic AT Command reference documentation contained this type of information. Instead of us just trying it and hoping that we find it out...

We simply cannot test all of the situations when the deployed devices are all around the world.

Could nordic try to add the min-max-arg response time to the AT Command reference guide? Or at least mark the one that might block in certain situations?

RE: AT%CONEVAL response time

Chris Burns — Wed, 21 Sep 2022 19:16:06 GMT

I have discovered that using the AT%CONEVAL command asynchronously ensures my thread doesn't block while waiting for the response. The response can still take a long time to respond, and this method results in other issues sometimes (see nrf_modem_at_cmd_async callback passes bad pointer).

RE: AT%CONEVAL response time

Kazi Afroza Sultana — Tue, 13 Sep 2022 20:35:59 GMT

Hello,

CONEVAL depends on the network conditions, and if there's a disrupt in the LTE link, things can take longer time or even time out due to the network being not available at that specific time. You can test with AT Client to see what the response is and can send us the output log. Our modem team can have a look.

Thanks.

Best Regards,

Kazi Afroza Sultana

RE: AT%CONEVAL response time

Achim Kraus — Tue, 13 Sep 2022 18:06:29 GMT

OK, if AT%CONEVAL is only used after CEREG=1 then that startup assumption doesn't work.

I guess you prefer an answer from the modem developers and not some ideas to try out.

RE: AT%CONEVAL response time

Chris Burns — Tue, 13 Sep 2022 17:56:10 GMT

To clarify: The AT%CONEVAL is send periodically (like every 500 msec for example) while the connection is active. It is only sent after a CEREG=1 is received from the modem.

A large majority of the time it returns very quickly.

But every once in a while it takes many seconds to return. This is the behavior I am trying to understand - why would the response time vary so wildly sometimes? And is there a way to use AT%CONEVAL which would never result in a long response time?

RE: AT%CONEVAL response time

Achim Kraus — Tue, 13 Sep 2022 05:28:12 GMT

> PSM is not enabled

Do you apply +CFUN=0/1 (power off/on) for energy management?

Just to say: in my opinion, that's not the intended way and the energy, that requires, will be disappointing.

In my experience, AT%CONEVAL returns always immediately, but I have the device "always on" and use PSM.

Reading the documentation, I'm not sure, if the data CONEVAL is based on, are kept over off/on. If not, then the device need to search for a network after it's enabled before it can return from CONEVAL. How long a full attach requires, is out of my scope.

A reattach to the network takes in my experience with NB-IoT (germany) usually 2-3s. Sometimes also up to 15s and in rare cases even longer. Maybe you wait, until the device reports LTE_LC_RRC_MODE_CONNECTED and LTE_LC_NW_REG_REGISTERED_HOME or LTE_LC_NW_REG_REGISTERED_ROAMING before calling AT%CONEVAL.

Not sure if that helps. As mentioned, I don't see these delays of CONEVAL on my devices.

RE: AT%CONEVAL response time

Chris Burns — Mon, 12 Sep 2022 21:12:00 GMT

The problem definitely occurs with NB-IOT - Cat-M has not been tested as extensively so I can't say whether it occurs at the same rate. PSM is not enabled.

RE: AT%CONEVAL response time

Achim Kraus — Sun, 11 Sep 2022 05:54:28 GMT

Does the nRF9160 use LTE-M or NB-IoT? Is PSM enabled?

RE: AT%CONEVAL response time

Chris Burns — Fri, 09 Sep 2022 15:31:27 GMT

I only mentioned the timer to say that sometimes the response to the AT%CONEVAL command took longer than 12 seconds. Often it returns very quickly, but sometimes it takes quite a long time.

I'm trying to understand if there are best practices regarding the AT%CONEVAL command. If there is a way to prevent the cases where it takes a long time I want to know so I can avoid them.

RE: AT%CONEVAL response time

Kazi Afroza Sultana — Fri, 09 Sep 2022 08:23:36 GMT

Hello,

There are several factors related for the accuracy of the evaluation result. You can try to run the AT command and show us the output log. ''I have a timer set for 12 seconds that will reboot the nRF9160 if it trips, and it trips with some regularity.' - Do you get the return from timer?

Thanks.

Best Regards,

Kazi Afroza Sultana