Configuration for - UDP over NB-IoT

RE: Configuration for - UDP over NB-IoT

StefanL — Thu, 20 Oct 2022 15:21:15 GMT

Thanks a lot for your help.

I'll then organize another SIM card which is permitted to connect via NB-IoT.

Kind Regards,

Stefan

RE: Configuration for - UDP over NB-IoT

Didrik Rokhaug — Thu, 20 Oct 2022 14:04:19 GMT

[quote user="StefanL"]I followed your advice and get more Details now (but it's quite cryptic to me :-D ).[/quote]

It can be a bit difficult if you don't know the code or the AT commands.

The interesting lines in this case is

D: +CEREG notification: +CEREG: 2,"5276","00285568",9,0,15<\r><\r><\n>

(and the one that is almost identical, but a different cell).

The line tells me that it tried to connect to a cell, but got rejected with reject cause "15".

The spec has this to say about reject cause 15:

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.

Again, not the easiest to understand, but it basically means that your subscription does not allow you to connect to the cell (but you might be allowed to connect somewhere else/other cells on the same network).

Which is what we would expect when you are allowed to use LTE-M on the network, but not NB-IoT.

RE: Configuration for - UDP over NB-IoT

StefanL — Thu, 20 Oct 2022 12:27:51 GMT

Hi Didrik

Thanks a lot for your super-quick support :-)

I followed your advice and get more Details now (but it's quite cryptic to me :-D ).

You may see quickly whats going on.

Kind Regards,

Stefan

*PS: I also followed your link to the network coverage page from iBASIS (it really seems the case that the card just not supports NB-IoT in Switzerland).

Here s the Log:

*** Booting Zephyr OS build 3afbbacd2ea2 ***
UDP sample has started
D: System mode (2) and preference (0) configured
D: +CEREG notification: +CEREG: 2,"0258","0102F8C9",9<\r><\r><\n>
D: Network registration status: 2
D: LTE mode: 9
D: Dispatching events:
D: - handler=0x00011F21
D: Done
D: Dispatching events:
D: - handler=0x00011F21
LTE cell changed: Cell ID: 16971977, Tracking area: 600
D: Done
D: Dispatching events:
D: - handler=0x00011F21
D: Done
D: +CSCON notification
D: Dispatching events:
D: - handler=0x00011F21
RRC mode: Connected
D: Done
D: +CEREG notification: +CEREG: 2,"0258","0102F8C9",9,0,15<\r>

D: Network registration status: 2
D: LTE mode: 9
D: +CSCON notification
D: Dispatching events:
D: - handler=0x00011F21
RRC mode: Idle

D: Done
D: +CEREG notification: +CEREG: 2<\r>

D: Network registration status: 2
D: LTE mode not found, error code: -22
D: Dispatching events:
D: - handler=0x00011F21
LTE cell changed: Cell ID: -1, Tracking area: -1
D: Done
D: Dispatching events:
D: - handler=0x00011F21
D: Done
D: +CEREG notification: +CEREG: 2,"5276","00285568",9<\r><\r><\n>
D: Network registration status: 2
D: LTE mode: 9
D: Dispatching events:
D: - handler=0x00011F21
LTE cell changed: Cell ID: 2643304, Tracking area: 21110
D: Done
D: Dispatching events:
D: - handler=0x00011F21
D: Done
D: +CSCON notification
D: Dispatching events:
D: - handler=0x00011F21
RRC mode: Connected
D: Done
D: +CEREG notification: +CEREG: 2,"5276","00285568",9,0,15<\r><\r><\n>
D: Network registration status: 2
D: LTE mode: 9
D: +CSCON notification
D: Dispatching events:
D: - handler=0x00011F21
RRC mode: Idle

D: Done
D: +CEREG notification: +CEREG: 2<\r><\r><\n>
D: Network registration status: 2
D: LTE mode not found, error code: -22
D: Dispatching events:
D: - handler=0x00011F21
LTE cell changed: Cell ID: -1, Tracking area: -1
D: Done
D: Dispatching events:
D: - handler=0x00011F21
D: Done

RE: Configuration for - UDP over NB-IoT

Didrik Rokhaug — Thu, 20 Oct 2022 12:10:24 GMT

Hi,

It doesn't look like iBasis have roaming agreements for NB-IoT in Switzerland:

https://ibasis.com/solutions/iot-connectivity/network-coverage/

iBasis eSIM International Coverage Update

What happens in the log is probably that it finds two different cells, tries to connect to them, but get rejected.

If you add CONFIG_LTE_LC_LOG_LEVEL_DBG=y to the prj.conf file, you should get more logs, to confirm that.

Best regards,

Didrik