Important update regarding LTE modem updates

[tuftec]

@xykon can you please advise the status of support for band 8.

When I use lte.attach(band=8) it reports band not supported.

If I use AT!="addband band=8" it just returns ok.

The published specifications for FiPy clearly indicate that band 8 SHOULD be supported.

It appears that some other users are having success with bands 20 and 3, but I can not get connection using band 8 which is required for Vodafone here in Australia.

How can I test that my command sequence is correct?

I can read the IMSI back from the SIM card, so I know the SIM card is working.
The SIM card has been provided by the Vodafone NB-IoT team here in Australia.

Please respond as soon as possible.

Peter.

[robert-hh]

@tuftec That's true. Glancing at the code, file esp32/mods/modlte.c, lines 370-480, shows, that band 8 is not supported by lte.atach(). It is however very easy to add that. The code structure is obvious.

[tuftec]

@robert-hh thanks. Would the other command method work though?

[robert-hh]

@tuftec The only thing this lte-attach() API does is send out AT commands for the supported bands like:

lte_push_at_command("AT!=\"RRC::addScanBand band=20\"", LTE_RX_TIMEOUT_MIN_MS);

So using the AT command directly or extending lte-.attach() works the same way.

[tuftec]

@tuftec where do I find the code?

Ok. So with me using the addband band=3 command this should effectively do the same thing.

[robert-hh]

@tuftec said in Important update regarding LTE modem updates:

addband band=3

Should'nt that be "addband band=8"

Edit: besides that, I've send a PR. Eventually it will be included.
Edit2: the code is in: https://github.com/pycom/pycom-micropython-sigfox/blob/master/esp32/mods/modlte.c

[tuftec]

@robert-hh no. Band 3 is required for operation in Australia with Vodafone.

Eventually is a long time.

Thanks

[robert-hh]

@tuftec OK. Band 3 is accepted by the API already. The actual set is 3, 4, 12, 13, 20 and 28. But that only means, it's forwarded to the Sequans firmware.

[Xykon]

I believe I found the issue with the modem not attaching. It’s a problem in the MicroPython firmware. Unfortunately I have to travel today and I’m currently in the train on the way to the airport.

If anyone with capabilities to modify & build the firmware can try this: in esp32/mods/modlte.c
Find && (strlen(pos) >= 31) && pos[30] == '7') {

Replace with && (strlen(pos) >= 31) && (pos[30] == '7' || pos[30] == '9')) {

Let me know if this helps I’ll try to build new firmware packages at the airport and at least try to make them available for manual flashing.

I’ve only tested this with the latest NB-IoT firmware.

As for the start-up commands, it seems Sequans has adapted the NB-IoT firmware to use largely the same startup code as CAT-M1.

So you can use the attach method as shown here https://forum.pycom.io/topic/3476/orange-belgium-gpy/7 or you can do the attach manually by sending the necessary AT commands.

For this, in a possible correction to my earlier post (I’m not entirely sure if it makes a difference), please try and replace the following two lines:

lte.send_at_cmd('AT!="addscanfreq band=20 dl-earfcn=6300"')
lte.send_at_cmd('AT!="zsp0:npc 1"')

with these:

lte.send_at_cmd('AT!="RRC::addScanBand band=20'")
lte.send_at_cmd('AT!="disablelog 1"')

However this should only be necessary if your band is not currently implemented in the firmware.

[robert-hh]

@xykon OK. I added that, w/o a difference. I did not expect any change, because the response to AT+CEREG? is always either 2,0 or 2,2. I'm monitoring the link between the ESP32 and the Sequancs chip, and there are unsolicited messages of alternating +CEREG: 0and +CEREG: 2 every 30 seconds. Other people may be more successful, which after the lte.send_at_cmd("AT+CEREG?") command receive a string, starting with +CEREG: 2,1 or +CEREG: 2,5

[Xykon]

@robert-hh Thanks for trying... for everyone else I have uploaded test firmware packages for GPy and FiPy at [LINK NO LONGER AVAILABLE]

I'll be travelling for the next 16 hours without access to Internet.

[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.