Important update regarding LTE modem updates

[tuftec]

@robert-hh Not sure what I was thinking in my earlier reply.
For clarification - BAND 8 is needed for Vodafone Australia!!!!!
Sorry about that.

[tuftec]

@xykon thanks.
Look forward to receiving further instructions.

[Xykon]

Another thing to try is sending the command lte.send_at_cmd('AT+CEMODE=0') before calling the attach method or lte.send_at_cmd('AT+CFUN=1').

This will configure the modem to use EPS attach instead of combined EPS/IMSI attach.

[stsiafak]

@tuftec Yes you are right. I have tried this and I am getting the message you describe. Seems there is a bug in the libraries because the hardcore commands (addScanBand, addScanFreqRange, addScanFreq) return no error in case using the value of 8(?). Have you tried something more robust like:

send_at_cmd_pretty('AT!="addScanFreqRange band=8 dl-earfcn-min=3450 dl-earfcn-max=3799"')

[tuftec]

@stsiafak I have not tried the pretty command at this point. Everything else I have tried does not seem to work.
I have not got the time to just keep trying different suggestions.
We need a clear direction from Pycom/Sequans to get this working.

[Xykon]

In regards to band 8, I was informed now that, while the hardware supports all bands (1,2,3,4,5,8,12,13,18,19,20,28), the Sequans firmware currently only supports a maximum of 6 bands so we chose the ones that gave us the best support at the time of launch. I have a call with Sequans later today to discuss this limitation and provide a firmware that can be used with band 8 as soon as possible. I hope to have an update on that within 24 hours.

[tuftec]

@xykon thanks

[tuftec]

@xykon I have been advised that for future compatibility with Vodafone's Australian network, all devices should support bands 5, 8 & 28. Currently only band 8 is supported.
If there is only a limitation in the modem firmware for only 6 bands, then maybe there should be a special version for Australia that will provide support for Vodafone, Telstra & Optus/Singtel.

[robert-hh]

@xykon How do I have to understand the answer. I read, that the set of bands the firmware can support is 6, but which bands are in this set of 6 can be freely chosen. If that is true, then there should be not problem, unless in a certain region more than 6 bands are used simultaneously.

[mfalkvidd]

@robert-hh with 12 bands to choose from, covering all possible combinations of 6 bands would require pycom to make 665,280 different firmwares available (12 * 11 * 10 * 9 * 8 * 7). I think that would be troublesome.

[robert-hh]

@mfalkvidd That is not required. Since lte.attach w/o parameters only send AT commands like:
AT!="RRC::addScanBand band=20"
to the device for the 6 supported bands, an user could also manually send these commands, or would call lte.attach(band=xx). It's only important, that the Sequans firmware could deal with that. And obviously, the should be a link the the docs to a table, where users could find the frequencies of interest.

[kevin]

@robert-hh The problem is that the underlying modem firmware from Sequans (e.g., NB1-38729) only supports bands 3/4/12/13/20/28. Operations involving other bands silently fail at the modem level, with no effect and no error messages.
Pycom was aware of this from the beginning, but it is still not resolved:
https://forum.pycom.io/topic/2496/gpy-readiness/8
Not sure if it is a lack of support from Sequans, or concerns over certification, or a deliberate strategy to control roll-out with selected partners. In any case it goes against the principle of "open development" that motivated many of us to choose Pycom/Sequans.

[kevin]

@xykon Pycom was looking into a "test" firmware from Sequans, supporting all 12 bands:
https://forum.pycom.io/topic/2496/gpy-readiness/18
That was 8 months ago, I guess it didn't work out? Can you look into that option again? Even if not fully calibrated/certified, it would work for lab testing.

[robert-hh]

@kevin So it seems that the decision for Sequans was not a lucky choice.

[Redferne]

Just tried upgrading a FiPy to Stable v1.18.1.r1 and LTE firmware NB1-38729. Seems to attach fine using Telia NB-IoT, however it will not let me connect due to this:

>>> lte.send_at_cmd("at+cops?")
'\r\n+COPS: 0,2,"24001",9\r\n\r\nOK\r\n'
>>> lte.send_at_cmd("at+cereg?")
'\r\n+CEREG: 2,5,"03F4","01A7561C",9\r\n\r\nOK\r\n'
>>> lte.isattached()
False
>>> lte.connect()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OSError: modem not attached

Sequans

+CEREG: <n>,<stat>[,[<tac>],[<ci>],[<AcT>[,<cause_type>,<reject_cause>]]]

Without digging in the code, is <stat> 5 properly handled as registered, roaming?

[robert-hh]

@redferne See thes post of @Xykon below, which try to address this:
https://forum.pycom.io/topic/3549/important-update-regarding-lte-modem-updates/84
and
https://forum.pycom.io/topic/3549/important-update-regarding-lte-modem-updates/86

[JoseDLopez]

@stsiafak Thanks for you answer!

Did you make that test in Chile? If it so, wich operator? I am trying with telefonica/movistar

Finally i am trying with Huawei Node and after:
.
.
lte.send_at_cmd('AT+CFUN=1')
.
.
lte.send_at_cmd('AT+CGATT=1')

I receive:
error +CEREG: 4

It seems to be a problem with freq band selected. Can you guide me about what does that error mean?

Maybe? Error Code: 4 -> Operation not supported

Best regards,

[tuftec]

@xykon please advise when we can expect a response to the band 8 problem.
I was surprised to discover that this issue has been known about for 8 months now.
This is a critical stop point for our project. We have already eaten up precious time that we have arranged with Vodafone Australia for system trials.
Peter.

[danielm]

I performed successful tests in NB-IoT network of Slovak Telekom with Sequans FW NB1-38729 and Pycom FW 1.18.1.r2 provided by @Xykon .

As suggested by @peterv it was possible to reduce the code to:

lte = network.LTE()
lte.send_at_cmd('AT+CGDCONT=1,"IP","nbiot.telekom.sk"')
lte.attach(band=20)

Issues which remain unsolved from my point of view are:

• working DNS over NB-IoT connection
• support of PSM and eDRX

[danielm]

There is one more issue. Test application was sending MQTT message once per minute. After approx. 5 hours MQTT client returned exception [Errno 113] EHOSTUNREACH and each following attempt to reconnect to MQTT broker was unsuccessful.
The application also checks lte.isattached() and lte.isconnected() in each loop and if there is a change of state it prints out notification. There were no notifications therefore I assume that state of both lte.isattached() and lte.isconnected() remained True.