Troubleshoot GPy connect to NB-IoT

[vli]

Hi,

Would like to seek advise on how to troubleshoot connecting GPy to NB-IoT network.

All firmware upgraded to the latest, and tested together with operator (Ericsson & use in-band), it seems cannot attach to the network, wonder if there is any AT command / suggested way to see whats wrong with it.

What I have tried so far in terminal:

from network import LTE
lte = LTE()
lte.send_at_cmd('AT+CFUN=0')
'\r\nOK\r\n'
lte.send_at_cmd('AT!="clearscanconfig"')
'\r\n\r\nOK\r\n'
lte.send_at_cmd('AT!="addscanfreq band=8 dl-earfcn=3741"')
'\r\n\r\nOK\r\n'
lte.send_at_cmd('AT!="zsp0:npc 1"')
'\r\n\r\nOK\r\n'
lte.send_at_cmd('AT+CGDCONT=1, "IP", "iotest"')
'\r\nOK\r\n'
lte.send_at_cmd('AT+CFUN=1')
'\r\nOK\r\n'
print (lte.isattached())
False

lte.send_at_cmd('AT+CEREG?')
'\r\n+CEREG: 2,4\r\n\r\nOK\r\n'
lte.send_at_cmd('AT+COPS=?')
''
By the way, what does lte.send_at_cmd('AT!="zsp0:npc 1"') do?

Cheers,
Vincent

[Eric Waai]

@vli
did you find a way to enable scrambling?
having the same problem here

[vli]

Hi All,

Simply if there is a way to enable NB-IoT Scambling Feature.

Cheers
vli

[vli]

Hi @jmarcelino

Tried by giving sufficient time after CFUN=1, still gives CEREG: 2,4.

Further discussed with their Engineer, they had similar experience (unable to attach) with other vendor's product and is wondering if the current radio firmware on GPy do comply/implemented with the Change Request specified in the 3GPP TS 36.211 as highlighted in the following table.

Regards,

Vincent

[vli]

Hi @jmarcelino

The EARFCN in use for LTE is 3750, the in-band EARFCN for NB-IoT is 3741 - thats the one reported from another working EVB from other chipset maker. I tried both but with no luck.

I will try again with longer wait time before checking if is attached.

Thx!

[jmarcelino]

Hi @vli

I take it that your dl-earfcn=3741 is correct for the network you're using?

Have you given sufficient time after CFUN=1 (30+ seconds)?

The "zsp0:npc 1" are internal Sequans commands unfortunately there's no public information on those we can share.