Unable to connect to R&S CMW500

[Alan Hasty]

Hello

We recently went to a test facility SGS, in San Diego, with our nrf9160 device trying to get a pre-cert scanning completed to find out if there are changes needed before we to our pre-production layout.

We were unable to get the modem to connect to the test equipment, R&S CMW500.

We have a Gemalto test sim on the board that has an R&S compatible test profile. ( see attachment below)

We are getting a signalling error when trying to setup the LTE connection. It appears to be passing the authentication check.

We are using the latest nrf9160 modem firmware 1.1, and before we switched the sims to the test sims, we verified the devices work on the m1 network on both ATT and Vzn networks. After the devices had the test sims installed, we were able to have the units boot and we were able to read the ICCID from the sim with the at commands.We set the device up to NOT run in PSM or ERDX mode.

There were two problems that were encountered.

The first is that the test equipment needed to have the link acknowledge set in order for the attach to happen.

The second is that once it was attached the test equipment was getting an RCC error.

I have attached the screenshots from the test equipment on the first issue

After changing the link acknowledge to "enable" the equipment was able to get to the next step and fail at the RCC establishment?

I have also attached the information on the test sim from Gemalto that we installed on the board for the purpose of connecting to the test equipment.

Gemalto LTE ADVANCED Test UICC 80.00 - Keys and Codes_External.pdf

So my questions are the following.

Why did the Nordic nrf9160 not connect to the test equipment? We have been connecting to ATT and Vzn towers/networks since last July(19) without issue.

Does anything in the setup of the modem need to change to be able to connect to the test equipment? If so, please share a document that describes what changes are necessary.

Please provide any documents Nordic may have on setup or configuration tips for the certification process.

We are hoping to find a test house local to the Dallas area that we can verify the connectivity before heading back out the the SGS facility.  Can you recommend any company or LTE /modem experts in Dallas that may be able to assist us ?

Please advise.

Thank you.

[Øyvind]

Hello, 

Sorry for the late reply, I have been out of the office for the last days. 

The technical support team does not work with R&S CMW500 that much, so I will need to contact one of our experts and see what they recommend.

Kind regards,
Øyvind

[Øyvind]

Based on your first screenshot, it looks like the CMW500 is configured to RLC UNACK which the nRF9160 does not support. Can you please reconfigure to RLC ACK: 

Connection->default bearer : Change from RLC UM to RLC AM


Thanks!

Kind regards,
Øyvind

[Alan Hasty]

Hi. Does this RLC setting address the RCC error mentioned above? Or the first which the link acknowledge was changed to get to the second RCC error?

[Øyvind]

I'm sorry, I do not have any details on this. Will need to forward your question to our CMW500 expert. 

-Øyvind

[Øyvind]

Hello, 

So the expert was able to reproduce what you see, and the first screenshot is because of incorrect RLC mode in the “default bearer” setting which you seemingly have solved in the second screenshot.

Furthermore, he instructs:

If you press “Connect” button in the 2^nd screenshot, RLC mode needs to be ack also in the pop-up window or in test mode dedicated bearer in GUI config menu (depending on callbox version).

But if you are directly trying to connect to the internet and get RRC connection reconfiguration error (around 20 seconds after attaching), can you save the configuration (with soft button) as a *.dfl file and attach to this ticket. This way, we can try here. Or if possible send tester / UE logs.

It would also help to know what procedure you are trying after attach.

Thanks!

[JuhaK]

Hello,

Are there plans to support RLC UNACK with nRF9160? If not, why? Traditionally/generally RLC UNACK seems to have been supported also within LTE Cat M1.

[Øyvind]

Hello JuhaK,

Can you please open a new ticket for you question? 

Thank you!

Kind regards,
Øyvind