problem about AT%XCBAND=?

[William.wei]

hi support team,

customer had one problem about "AT%XCBAND=? "

first. Customer try to set catm and catnb systemmode together as below, i could not see the band17 in list:

[16:43:53.099] AT%XFACTORYRESET=0

[16:48:21.233]

[16:48:21.233] OK

[16:48:21.233] AT%XFACTORYRESET=1

[16:48:23.659]

[16:48:23.659] OK

[16:48:23.659] AT%XBANDLOCK=1,"10001100000001010"

[16:48:26.335]

[16:48:26.335] OK

[16:48:26.335] AT%XBANDLOCK=2,"10001100000001010"

[16:48:29.173]

[16:48:29.173] OK

[16:48:29.173] AT%XCBAND=?

[16:48:32.368]

[16:48:32.368] %XCBAND: (2,4,12,13)

then we change systemmode to catnb only, it shows band17 as below:

[16:49:16.633] AT%XSYSTEMMODE=0,1,0,0
[16:49:21.557]
[16:49:21.557] OK
[16:49:21.557] AT%XCBAND=?
[16:49:26.089]
[16:49:26.089] %XCBAND: (2,4,12,13,17)

then. i start the modem as AT+CFUN=1, the band 17 show quite slow:

[16:49:56.018] AT+CFUN=1

[16:50:02.586]

[16:50:02.586] OK

[16:50:02.586] AT%XCBAND=?

[16:50:08.516]

[16:50:08.516] %XCBAND: (2,4,12,13)

[16:50:08.516]

[16:50:08.516] OK

[16:50:08.516] AT%XCBAND=?

[16:50:13.511]

[16:50:13.511] %XCBAND: (2,4,12,13)

[16:50:13.511]

[16:50:13.512] OK

[16:50:13.512] AT%XCBAND=?

[16:50:18.510]

[16:50:18.510] %XCBAND: (2,4,12,13)

[16:50:18.512]

[16:50:18.512] OK

[16:50:18.512] AT%XCBAND=?

[16:50:23.519]

[16:50:23.519] %XCBAND: (2,4,12,13,17)

[16:50:23.519]

[16:50:23.519] OK

the question is ,is there any reason for this command? 

Regards,

William.

[Håkon Alseth]

Hi William,

 

We do not support band 17 on LTE-M, as stated here in the release notes for the mfw v1.3.6:

*** mfw_nrf9160_1.3.6
*********************

The mfw_nrf9160 is the firmware for the modem subsystem of nRF9160. It supports 3GPP LTE release 13
LTE-M and NB-IoT standards, selected optional 3GPP LTE release 14 features, GPS L1C/A and QZSS L1C/A
positioning.

LTE-M operation is enabled on E-UTRA Bands 1, 2, 3, 4, 5, 8, 12, 13, 18, 19, 20, 25, 26, 28 and 66.

NB-IoT operation is enabled on E-UTRA Bands 1, 2, 3, 4, 5, 8, 12, 13, 17, 19, 20, 25, 26, 28 and 66.

 

Also reflected here in the chart:

https://www.nordicsemi.com/Products/Wireless/Low-power-cellular-IoT/nRF9160-Revision-1-global-and-regulatory-certifications

  

Kind regards,

Håkon

[William.wei]

yes,Hakon

i understand your meaning, my point is band 17 is not listed at the first moment, but shows at about 10 seconds later.

we have any reason for this?

William.wei said:

[16:50:13.512] AT%XCBAND=?

[16:50:18.510]

[16:50:18.510] %XCBAND: (2,4,12,13)

[16:50:18.512]

[16:50:18.512] OK

[16:50:18.512] AT%XCBAND=?

[16:50:23.519]

[16:50:23.519] %XCBAND: (2,4,12,13,17)

Regards,

William.

[Håkon Alseth]

Hi William,

 

My apologies for misunderstanding the scenario.

I tried to recreate this locally, but was not able to do so:

[2024-11-15 13:59:38] *** Using Zephyr OS v3.7.99-adcffa835a8e ***
[2024-11-15 13:59:38] The AT host sample started
[2024-11-15 13:59:38] Ready
[2024-11-15 13:59:43] AT%XFACTORYRESET=1
[2024-11-15 13:59:44] OK
[2024-11-15 13:59:50] AT%XBANDLOCK=1,"10001100000001010"
[2024-11-15 13:59:50] OK
[2024-11-15 13:59:54] AT%XBANDLOCK=2,"10001100000001010"
[2024-11-15 13:59:54] OK
[2024-11-15 13:59:58] AT%XCBAND=?
[2024-11-15 13:59:59] %XCBAND: (2,4,12,13)
[2024-11-15 13:59:59] OK
[2024-11-15 14:00:04] AT%XSYSTEMMODE=0,1,0,0
[2024-11-15 14:00:09] OK
[2024-11-15 14:00:10] AT%XCBAND=?
[2024-11-15 14:00:10] %XCBAND: (2,4,12,13,17)
[2024-11-15 14:00:10] OK
[2024-11-15 14:00:19] at+cfun=1
[2024-11-15 14:00:21] OK
[2024-11-15 14:00:21] AT%XCBAND=?
[2024-11-15 14:00:21] %XCBAND: (2,4,12,13,17)
[2024-11-15 14:00:21] OK
[2024-11-15 14:00:22] AT%XCBAND=?
[2024-11-15 14:00:22] %XCBAND: (2,4,12,13,17)
[2024-11-15 14:00:22] OK
[2024-11-15 14:00:23] AT%XCBAND=?
[2024-11-15 14:00:23] %XCBAND: (2,4,12,13,17)
[2024-11-15 14:00:23] OK
[2024-11-15 14:00:23] AT%XCBAND=?
[2024-11-15 14:00:23] %XCBAND: (2,4,12,13,17)
[2024-11-15 14:00:23] OK

Which modem fw are you running? This can be read out using "at+cgmr"

I was running this on mfw v1.3.6.

 

Kind regards,

Håkon

[William.wei]

yes Hakon,

the same mfm1.3.6 as you.

You are reproducing my question, you can set AT%XSYSTEMMODE=1,1,0,0, and please try again.

you can see that %XCBAND: (2,4,12,13,17) appears at about 15 seconds.

Regards,

William.

[Håkon Alseth]

Hi William,

 

If we look at the documentation for XSYSTEMMODE:

https://docs.nordicsemi.com/bundle/ref_at_commands/page/REF/at_commands/mob_termination_ctrl_status/xsystemmode_set.html

You are enabling both NB + LTE-M modes, then enabling the modem. It will start up with LTE-M and then switch over to NB-IoT. Could this be the reason why you're seeing this behavior?

 

Try setting "at+cereg=5" and checking the return (at+cereg?) for each time you poll the %XCBAND to verify which mode is used.

 

Kind regards,

Håkon