nrf9160 not able to connect to Bands other than 12

[Stratosphere]

modem: 1.2.3

sdk: 1.4.2 and 1.6

We have been trying to test LTE performance on different bands but so far we have not been able to use BANDLOCK to limit the connection to only certain bands.

We are in Toronto, Canada and have tried to use 3 different SIMs (Bell, Hologram, iBasis) and none of them can connect to any band other than band 12. I have also tried with a few different off-board antennas as well as tried connection from 3 different physical locations (Brampton, Vaughan and Mississauga) and nothing has worked so far.

This is the code that I have been testing with and only band 12 seems to work. I am not sure if I have to perform any other operation before locking a band. For testing, I am physically disconnecting power to our custom board between each test.

//if (at_cmd_write("AT%XBANDLOCK=2,\"1000000000000100000011010\"", NULL, 0, NULL) == 0)

//if (at_cmd_write("AT%XBANDLOCK=2,\"1000000000000000000011010\"", NULL, 0, NULL) == 0)

if (at_cmd_write("AT%XBANDLOCK=2,\"1000000000001000000011010\"", NULL, 0, NULL) == 0)
{
  printk("Band lock set\n");
}

Regards

[helsing]

Thank you for your reply. 

What do you currently see in the log after XBANDLOCK? 

Could you please confirm that you are setting the band lock before activating modem with +CFUN? I assume, however, that you would have seen an error if you tried the opposite order.

How do you currently verify which band is working? Something to try is to activate the modem without using XBANDLOCK, and then use XCBAND to check the active bands(XCBAND works only after the modem is activated). 

Looking at line 5 of the code you posted: Are you selecting band 13(and not band 12) on purpose? Is that in order to make band 12 unavailable? 

An alternative to XBANDLOCK is to update your prj.conf with the following configs:

CONFIG_LTE_LOCK_BANDS  and CONFIG_LTE_LOCK_BAND_MASK, for example like this:

CONFIG_LTE_LOCK_BANDS=y

CONFIG_LTE_LOCK_BAND_MASK="00000000000000000010"

Have you tried using XBANDLOCK with the at_client sample? 

[Stratosphere]

Hi Hakan, 

Thanks for your response.

1. I will check the log again and get back to you tomorrow about what I see after XBANDLOCK. When i try the band lock on Band 12, everything works well. Setting it to any other band is where LTE Connection is not established.

2. We have almost 20 devices in the field. They all submit band information and they all run band 12. I have on a couple of occassions seens devices connect to band 4 but that is 1 in a 100 occurance. This is without any bandlock.

3. Yes, I was trying band 13 in line 5 instead of band 12 just as one of the tests.

4. I will try the proj.conf settins as you suggested and get back to you tomorrow.

5. I have not tried it using at_client.

I just purchased a thingy91 and I was trying this XBAND code on their. The asset tracker example was working out of the box but after updating my code, it does not connect to any bands at all. I remember seeing somewhere about adding a MAGPIO config line in the code to properly configure the active tuner but I can't find that now. Can let me know what line is that I need to add to configure the MAGPIO on thingy91? This test should let me compare Antenna performance on various bands between thingy91 and our board and possibly indicate/elimiate any hardware issues

Regards

Noaman

[helsing]

Hi Noaman,

Stratosphere said:

after updating my code

What changes did you make? Which sample are you building? And which board are you building for?

Stratosphere said:

Can let me know what line is that I need to add to configure the MAGPIO on thingy91?

MAGPIO is set automatically when you are building for Thingy:91. If you want to use Band 4 at 850MHz, then the correct MAGPIO pins will be changed automatically whenever that frequency is in use. Here is how MAGPIO is configured automatically:

In the file board_nonsecure.c, located in v1.7.0/nrf/boards/arm/thingy91_nrf9160/, you will find the following.

#define AT_CMD_MAGPIO       "AT%XMAGPIO=1,1,1,7,1,746,803,2,698,748," \

                "2,1710,2200,3,824,894,4,880,960,5,791,849," \

                "7,1565,1586"

The command is given to the modem at startup.

The setup corresponds more or less with Thingy:91 User Guide, section 5.3.1. Antenna tuning. The configuration is, as you say, set up with MAGPIO configuration %XMAGPIO and the MAGPIO set command.

Please let me know if you would like to make changes to the settings, and I will look up exactly how this is done. I think the way to do this is something like adding the below configs to prj.conf but I have not tested this myself:

CONFIG_NRF9160_GPS_SET_MAGPIO=y
CONFIG_NRF9160_GPS_MAGPIO_STRING="AT%XMAGPIO=1,1,1,7,1,746,803,2,698,748,2,1710,2200,3,824,894,4,880,960,5,791,849,7,1565,1586"

Best regards,

Håkon

[Stratosphere]

Hi Haken,

After many tests I am still unable to connect to any band other than Band 12.

Band 12 connects right away but other bands just do not work.

I tried on Thingy91 with AT Client example and At LInk Monitor.

I have tried using BandLock command and it is working as I can see the Bands update on the GUI as well as when I send out AT%XBANDLOCK? 

I have tried manually sending the MAGPIO command to set different different band settings as well but all without success. 

At this point, I can safely say that the device just won't connect to any Bands other than 12.

Are you aware of any such behavior in Canada?

[Håkon Alseth]

Hi,

 

Are you sure that LTE M (or NB1) is available on other bands in your area?

Do you get connected on other bands with a nRF9160-DK/thingy91 for instance?

If you lock the bands to the other band, then do a manual search using AT+COPS=? it should return any network it finds. If it does not find any, it's highly likely not available in your area.

 

Kind regards,

Håkon