experiencing packet loss when there is an LTE BAND switch

[Praveen Deshmane]

Hello DevZone community,
I'm working on a project with the nRF9160 module, and
I'm curious to know if anyone has experience with maintaining stable communication when the LTE BAND switches.
Have you encountered any issues or packet loss in such scenarios, and
if so, how did you address them? 

My Environment

NCS - SDK 1.9.1
Modem version - 1.3.2
Device - nrf9160 customized one

I am sharing the information below when band switching occurs in driving tests.
You can see that when LTE band switch occurs, the device was not able to send the GPS data to our server nearly 20 seconds.
NOTE:
We are sending the time info for every 10 second and GPS info every 50 meters distance.



Your insights would be greatly appreciated!"

Unfortunatelly I am unable to get the modem trace and lte_lc debug logs in my customized device. I have seperate ticket for that.  
https://devzone.nordicsemi.com/f/nordic-q-a/102257/build-error-during-modem-trace-collection---nrf9160

Best Regards

Praveen Deshmane

[Øyvind]

Hello, 

In order for us to see what is going on with the device and network we will need a modem trace. I see you have closed the ticket regarding the issues with modem trace, which will not solve that issue.

Have you ensured that the device is correctly switching between RRC Idle mode or power saving mode (PSM), or when the LTE modem is completely deactivated. Any logs from the application including more debug information that you can provide to us? 

Are you switching the band or does this happen during location changes i.e. switching base station? Have you tried to lock your device to one band using Band lock %XBANDLOCK?

What network are you operating in?

Thanks.

Kind regards,
Øyvind

[Praveen Deshmane]

Hello Oyvind,

Thank you for your reply and time.

 Are you switching the band or does this happen during location changes i.e. switching base station?

This happens during location changes. (During driving test - we car keeping the device inside a car and testing).

The network is - 5G, and the service provider is IIJ global japan.

We have tried to using lock your device to one band using Band lock %XBANDLOCK 

I will share the result soon.

Have you ensured that the device is correctly switching between RRC Idle mode or power saving mode (PSM), or when the LTE modem is completely deactivated. Any logs from the application including more debug information that you can provide to us? 

We are investigating about it.

Best Regards

Praveen Deshmane

[Praveen Deshmane]

Hello Oyvind, 

The status of the nrf9160 is monitored after LTE is established.

At that time, an event occurred in which RSRQ became 0.

What does 0 RSRQ mean in NRF9160? (Is it okay to treat it as out of range?) 

Best Regards

Praveen Deshmane

[Øyvind]

...

Reference Signal Received Quality (RSRQ) around zero looks like bad signal quality. Are you seeing the same with e.g. nRF9160DK? Would be good to rule out any issues with custom board.