Can the nRF9151 DK connect using standard LTE (Cat-1/4), or only LTE-M / NB-IoT?

[jazorrop]

Hi, I'm working with the nRF9151 DK and currently going through the Cellular IoT Fundamentals course. In Lesson 4, it states that we should see a message indicating a successful connection to the LTE network. However, I noticed some inconsistencies during testing.

From what I understand, the nRF9151 supports only LTE-M (Cat-M1) and NB-IoT (Cat-NB1/NB2), as stated in the official documentation. There's no mention of support for standard LTE (e.g., Cat-1 or Cat-4).

When I insert a regular SIM card (without LTE-M/NB-IoT support), the code from Lesson 4 runs and outputs:

<inf> Lesson4_Exercise1: Initializing modem library 
<inf> Lesson4_Exercise1: Connecting to LTE network 
<inf> Lesson4_Exercise1: RRC mode: Connected 

But it never reaches the “IPv4 address found” message, which works fine when I use a SIM card with LTE-M support.

My questions are:

1. Is the nRF9151 DK limited to LTE-M and NB-IoT only, or is there any way to force it to use standard LTE (Cat-1/4) with a regular SIM?

2. If it's LTE-M/NB-IoT only, is there a known workaround or test setup that allows developers to simulate or route data via standard LTE for testing purposes?

3. Could the behavior I'm seeing—stopping at “RRC mode: Connected”—indicate it's connected to an unsupported network type?

I appreciate any clarification or advice from the community. Thanks in advance!

[Øyvind]

Hello, 

Is the nRF9151 DK limited to LTE-M and NB-IoT only, or is there any way to force it to use standard LTE (Cat-1/4) with a regular SIM?

Yes, the nRF9151 SiP supports LTE-M and NB-IoT only. I.e.

• 3GPP LTE release 14 Cat-M1 compliant
• 3GPP LTE release 14 Cat-NB1 and Cat-NB2 compliant

It will not work with other SIM cards that do not support LTE-M and/or NB-IoT.

If it's LTE-M/NB-IoT only, is there a known workaround or test setup that allows developers to simulate or route data via standard LTE for testing purposes?

No, there are no known workarounds to connect via LTE SIM with no LTE-M and/or NB-IoT support.

1. Could the behavior I'm seeing—stopping at “RRC mode: Connected”—indicate it's connected to an unsupported network type?

I would recommend programming the AT client found in the precompiled package under Downloads of the nRF9151DK product page. Then you can use the Cellular Monitor to evaluate the connection. What SIM card are you using with your device?

The RRC mode: Connected would indicate that your device is connected to the network. See Lesson 1 of the Cellular Fundamentals course. 

Kind regards,
Øyvind

[Achim Kraus]

Just to add:

"RRC active" is entered here in order to register the modem in the network. Without subscription (SIM) you usually get a couple of RRC active events, but the registrations short later will be rejected.

jazorrop said:

If it's LTE-M/NB-IoT only, is there a known workaround or test setup that allows developers to simulate or route data via standard LTE for testing purposes?

I'm struggling to see your point. If you have SIM cards, which supports LTE-M/NB-IoT and that works, why do you want to use something else? Or is the development located in a region without LTE-M/NB-IoT?

To be frank, if you want a reliable and resilient application, you will need a development able to test efficiently. Otherwise the tests will become a pretty expensive nightmare. Therefore I would recommend to have at least some parts of the development done in a region with LTE-M/NB-IoT.