BG95-M3 NB-IoT connection only possible after eMTC-connection

IoT Modules LPWA Module
1

Hi!

We are using the BG95-M3 modul.

We have noticed, that for brand new devices, the following settings prevent the device from getting conncted:

AT+QCFG=nwscanmode,0,1
AT+QCFG=nwscanseq,00,1
AT+QCFG=iotopmode,2,1

So far, the device has not been connected and will not connect.

With the following settings I can connect:

AT+QCFG=nwscanmode,0,1
AT+QCFG=nwscanseq,0201,1
AT+QCFG=iotopmode,0,1

After this I change back to the original settings (include NB-IoT and automatic sequence) and the device is still able to connect.

Is that behaviour meant to be like that or am I missing something?

Best regards,
Martin

2

please try
AT+CFUN=0
AT+QCFG=nwscanmode,0,1
AT+QCFG=nwscanseq,0201,1
AT+QCFG=iotopmode,0,1
AT+CFUN=1

3

Hi,

with those settings I’m already able to connect, no problem.

But I’d like to use
AT+QCFG=nwscanseq,00,1
AT+QCFG=iotopmode,2,1

which doesn’t work if the device was never connected before.

4

You need to manually configure the parameters before the modem searches for the network because the history of the camped cell can be quickly searched in the short time after the terminal is powered on

5

Thanks for your help.

But to be honest, I don’t understand this “workaround”. For my understanding, the

AT+QCFG=nwscanmode,0,1
AT+QCFG=nwscanseq,0201,1
AT+QCFG=iotopmode,0,1

is a reduced network scan (without NB-IoT). From the original settings, nwscanseq (00 - automatic) is defined to use NB-IoT when eGSM is not available and it is allowed to use both eGSM and NB-IoT in iotopmode.

Do I understand wrong?

Best regards,
Martin

6

yes,I think you understand correctly

7

So, I have a factory new device that is configured as follows:

AT+QCFG=nwscanmode,0,1
AT+QCFG=nwscanseq,00,1
AT+QCFG=iotopmode,2,1

Why is not able to establish a connection to the network? Or am I having a problem with a timeout because of a long connection time with these settings at first connection try?

8

Hi,

I do have same observation. For a never connected device (or if I manually flush LOCI information in the SIM), the optimal setup for NB-IoT isn’t working, device is silent and not trying to attach:

AT+CFUN=0
AT+QCFG=“iotopmode”,1
AT+QCFG=“nwscanseq”,03
AT+QCFG=“nwscanmode”,3
AT+CFUN=1,1

Workaround is to apply another setup, and then yes, after first connection, I can revert to the NB-IoT specific one and device will connect properly at next power cycle.

I’m afraid is related to the RAT order decision when in the SIM all is void.

Thanks!