Troubleshooting test basestation connection issue during certification

[Zoltan Ban]

test_failure_report.zip

Dear Nordic Team,

We have a custom device based on our beloved nRF9160 SiP. For one of our partners, certifying our device is mandatory. We took part in radio signaling testing (part of a RED certification in Germany) but our device failed to connect to the test station (R&S CMW500). I had several hours to make it work but could not manage it. Our device is already in the pre-production phase, and we had no connection issues that we couldn't solve, so I think our logic is correct. I also tried to make our device and the nRF9160DK as well to connect to the test station using the modem shell sample application and using the at_client sample application too.
The problem, in a nutshell, is the following, we confirmed that the device found the base station ( we also saw it on the test station event log ), and tried to connect to it, but it failed.
Unfortunately, having more information (log) from the base station was not possible. I collected as many logs as I can during the process on the device side.
I also reviewed the article about this configuration. I attaching all the data I collected during the test, you can find the exact hardware and modem firmware versions in them.

My wish would be to get advice, on what went wrong, why we couldn't manage to connect to the test station, and how we can make it work. Passing this test is a requirement for the certification, and our partner can not use our device without having the right certifications.

Thank you in advance!
Have a nice day
Zoltan

[Håkon Alseth]

Hi,

 

Unfortunately, the modem traces (*.bin files) were empty, so I'll have to give directions based on the .txt logs.

at_client_1.txt shows:

...
+CEREG: 2,"C364","01E15B08",9
+CNEC_EMM: 15
+CEREG: 2,"C364","01E15B08",9,0,15
...

EMM return code of 15 means that you're not allowed to connect to the specific network:

Cause #15 – No suitable cells in tracking area

      This EMM cause is sent to the UE if it requests service, or if the network initiates a detach request, in a tracking area where the UE, by subscription, is not allowed to operate, but when it should find another allowed tracking area or location area in the same PLMN or an equivalent PLMN.

NOTE 3:  Cause #15 and cause #12 differ in the fact that cause #12 does not trigger the UE to search for another allowed tracking area on the same PLMN.

The CellID here is different from what is shown in the other logs:

+CEREG: 2,"C2FA","002E7F67",9
▸[MODEM] Searching for networks
▸[MODEM] LTE cell changed: Cell ID: 3047271, Tracking area: 49914
▸[MODEM] LTE mode updated: NB-IoT

 

This indicates that the nRF9160 is trying to connect to actual live networks in your area, and not the tester network.

Without any logs from the CMW-500, it is hard to say what specifically is wrong here, but it all points to incorrect configuration on the tester itself.

 

Kind regards,

Håkon