Unable to connect to nRF9160 with R&S CMW500

[David Palchak]

We are having difficult getting a R&S CWM500 to connect to our nRF9160-based device (operating in CAT-M1 mode). We are using a R&S test UICC. We have already attempted all of the settings changes documented in the following issues:

 when i connect NRF9160-DK to the CMW 500 for CAT-M test, the NFR9160 can register with CMW500, but the connect drop very quickly, 

 Using nRF9160 against R&S CMW500 (or CMW290) in signalling callbox mode 

 NRF9160 RRC Connection Re-established CMW500 

 Unable to connect to R&S CMW500 

Here are some screenshots of the CMW500 configuration that we have tried:

Finally, here is a copy of the full CMW-500 configuration that we tried:

CMW500 settings, Signaling failure, Boosty Device, 2022-10-27.zip

The devices we are testing are pre-production devices, which means that we do not have immediate access to any logging output at the moment. Additional connectors would have to be reworked on to the board to permit this, and the test facility (where the boards are) is located in a completely different region of the country.

Any guidance that you can provide on what setting(s) might need to be adjusted on either the nRF9160 or the CMW-500 would be tremendously helpful.

Cheers,
David

[Didrik Rokhaug]

Hi,

What application is running on the device?

How does the application behave if it doesn't have internet connectivity?

Have the test house tried the .dfl's attached to one of these guides?

 Using nRF9160 against R&S CMW500 (or CMW290) in signalling callbox mode 

https://devzone.nordicsemi.com/power/w/opp/4/user-guide-lte#h54skc3ia2mr1m1t0sg1piiyrk1cmx8n8

What is the RLC mode of the default bearer? (should be "Acknowledged")

Best regards,

Didrik

[David Palchak]

Hi Didrik,

The device is running a custom application. The correct operation of the application has been been confirmed with multiple independent eUICC and UICC devices from different carriers.

For you question on how the application behaves if it doesn't have internet connectivity, do you mean how does it behave if it cannot establish a radio link, or how does it behave it the default bearer does not provide Internet connectivity?

Upon boot the application attempts to initialize the modem and then attempt to connect to a network using the default profile on the eUICC. If a network connection is never established, the device simply suspends further initialization and ignores future attempts to perform network-dependent operations (such as retrieving the current time, sending data, etc).

The settings file (DFL) attached to the first link has been tried. We will try the settings file mentioned in the second link and report back.

Cheers,
David

[Didrik Rokhaug]

David Palchak said:

For you question on how the application behaves if it doesn't have internet connectivity, do you mean how does it behave if it cannot establish a radio link, or how does it behave it the default bearer does not provide Internet connectivity?

I was thinking about lack of internet connectivity. We have seen cases where the test houses have been using e.g. the asset_tracker_v2 as the application, while they want to test the LTE stack.

However, because the asset_tracker_v2 will turn off LTE if it is not able to connect to the server, they were not able to do their tests.

David Palchak said:

The settings file (DFL) attached to the first link has been tried. We will try the settings file mentioned in the second link and report back.

Please let me know if it works or not.

[David Palchak]

We tried both settings files, and one of them worked and one of them did not. We will proceed with the settings file that worked. However, it's interesting that there is a difference between the two. I don't know what that difference is, but it's worth figuring out so that others don't keep getting tripped up by this same problem. There seem to be a lot of dev zone posts about this exact same issue....

Cheers,
David

[Didrik Rokhaug]

That's great to hear.

David Palchak said:

However, it's interesting that there is a difference between the two. I don't know what that difference is, but it's worth figuring out so that others don't keep getting tripped up by this same problem.

Just so we are clear, which file did they use that worked (and which files did they try that did not work)?

Between the two blog posts I linked, there are 4 configuration files.

Anyway, my guess would be that one of the files are configured for LTE-M, and the other for NB-IoT, while your application only supports LTE-M.

[David Palchak]

The settings file that worked is the one from the zip archive "M1_configuration file for signalling.zip" that was attached to this article:

 Using nRF9160 against R&S CMW500 (or CMW290) in signalling callbox mode 

Both of the files that we tried are purported to be for LTE-M signaling, so it seems unlikely that it was a LTE-M vs -NBIoT thing.

[Didrik Rokhaug]

Assuming "RSRP RSRQ meas.zip" is the other config file, that failed, this is what I am told is the difference:

"RSRP RSRQ meas.zip" shows own cell Cat-M measurements in the CMW500 GUI by reporting RSRP and RSRQ using measurement reports for half-duplex device like nRF9160.