Roaming SIM card from Soracom sluggish on NB-IoT

RE: Roaming SIM card from Soracom sluggish on NB-IoT

Burt — Wed, 14 Feb 2024 20:54:04 GMT

Having thought about it, I see how AT+CFUN=0 can be used to lock in a PLMN without having to create a special build with the extra config options. That may be useful. I will close the ticket.

RE: Roaming SIM card from Soracom sluggish on NB-IoT

Burt — Wed, 14 Feb 2024 03:22:56 GMT

After all these weeks, I now see that I had misread the suggestion 3 from Soracom. I read only the first few words carefully, about caching network information to the SIM. I completely missed the fact that they were telling me to find a device faster than the nRF9160! That really does seem impractical, and I would not have asked about it if I had read the suggestion more carefully.

Jonathan, you pointed me to the asset_tracker architecture, but you did not point me to any documentation regarding the use of AT+CFUN=0 for speed up. Although the AT Commands Reference explains what gets stored in NVRAM, it does not give me a feel for what amount of speed up time to connection might be. That's what I am looking for, if you can dig up anything from the knowledge inside your company. Thanks.

Burt

RE: Roaming SIM card from Soracom sluggish on NB-IoT

Burt — Tue, 13 Feb 2024 15:51:17 GMT

Thanks, Jonathan. I see that Soracom has a help center, their DevZone you might say, so I will contact them next to get their take on pre-caching network information in the SIM. I'm not certain that the asset tracker documentation will move me forward on this ticket's question but reading the Modem module section has given me an idea for investigating a different problem the boss has mentioned: on rare occasions, our (modified) asset tracker has been known to disconnect but not reconnect. Thanks for the link to the tracing instructions, too.

Burt

RE: Roaming SIM card from Soracom sluggish on NB-IoT

JONATHAN LL — Tue, 13 Feb 2024 13:26:30 GMT

Sorry for the delay Burt,

Using CFUN=0 once should be enough when the device is stationary but sometimes the bastion it connects to change for whatever reason so running the CFUN=0 every once in a while can be smarts, but not often.

[quote user="Burt"] I am looking to have a clearer high level picture overall. Maybe pseudo code would help me.[/quote]

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/applications/asset_tracker_v2/doc/asset_tracker_v2_description.html this documentation is comprehensive and does provide all the parts of the application.

And here you can see a flowchart of the prosess: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/applications/asset_tracker_v2/doc/app_behavior.html#real-time-configurations

[quote user="Burt"]If I were to send you logs, what should I configure for that in prj.conf to be useful?[/quote]

You can follow the info her https://infocenter.nordicsemi.com/topic/ug_trace_collector/UG/trace_collector/enable_tracing.html?cp=11_3_5_3_1 , A modem trace will provide us with the most details about what is happening.

Regards,
Jonathan

RE: Roaming SIM card from Soracom sluggish on NB-IoT

Burt — Wed, 24 Jan 2024 23:47:35 GMT

Hi Jonathan,

You have mentioned CFUN=0 especially in the case that the tracker unit is moving all around. Actually, our trackers are fixed position, but nevertheless I would like to understand how one would use CFUN=0 in the non fixed position case. Am I correct that you are describing something that is not built into the asset_tracker_v2 code? I am looking to have a clearer high level picture overall. Maybe pseudo code would help me.

I understand that there are some commands like %XBANDLOCK, %XSYSTEMMODE, %XPTW, %XCOUNTRYDATA, +COPS, and %CSUS to which their configuration will be stored in NVM after +CFUN=0. But consider for example what I wrote earlier

CONFIG_LTE_LOCK_PLMN=y
CONFIG_LTE_LOCK_PLMN_STRING="310260"

I think this bit of configuration causes +COPS to execute every time I power up the device. If instead, I made certain to store the configuration just once in NVM and on future power ups relied on the NVM settings, this would not speed up my connect time to LTE noticeably, would it?

If I were to send you logs, what should I configure for that in prj.conf to be useful?

That's all I can think of. Thanks.

Burt

RE: Roaming SIM card from Soracom sluggish on NB-IoT

JONATHAN LL — Wed, 24 Jan 2024 09:30:09 GMT

Hi Burt,

Don't have anything else to contribute with not extra logs or such to look at. My guess is that CFUN=0 is you best friend here. But if there is any issues or related questions feel free to ask and i will do my best to help.

Regards,
Jonathan

RE: Roaming SIM card from Soracom sluggish on NB-IoT

Burt — Mon, 22 Jan 2024 15:35:54 GMT

Hi Jonathan,

Thank you for the useful information regarding CFUN and %XCOUNTRYDATA.

Regarding your questions, I have not been in contact with Soracom. I don't have any interesting logs, but I can say that the connection time is repeatable multiple times with the same SIM card. So, I guess there is no special SIM caching to automatically speed things up (as the connection time is repeatable and doesn't decrease), and no obvious way to change that from the asset tracker v2 application. I am going to assume that the techniques available to me are what you have presented here, unless you come up with anything else. Thanks again.

Burt

RE: Roaming SIM card from Soracom sluggish on NB-IoT

JONATHAN LL — Mon, 22 Jan 2024 13:27:40 GMT

Also,

CFUN=0 should be a better option for some use cases. So if the tracker unit is moving all around then this will help improve time to connection in many cases. Be sure to not over use the command as it will wear out NVM.

If the tacker is only in one location, or is within a area there only the same network is used then locking like you have tested can be the better option. But if the device leaves the area it will not be able to find a new band to connect to as it is locked.

Then there is the %XCOUNTRYDATA that is some where in-between. It will help in many cases where deices stays whit in the same country.

Regards,
Jonathan

RE: Roaming SIM card from Soracom sluggish on NB-IoT

JONATHAN LL — Mon, 22 Jan 2024 12:39:25 GMT

Hi,

Have you been in contact with Soracom?

Can you provide some logs of the situation where this is happening.

This connection time is repeatable multiple times with same SIM card and and device?

Regards,
Jonathan