GPS/LTE_M/NB-IoT nRF91

[Hoang]

Dear, 

I am using :

ncs: v0.4.0 

SES 4.16 

firmware: mfwnrf916007029alpha

Hardware: nRF9160 DK v: 0.8.5

I want to do: 

1. Enable and get GPS position ("AT\%XSYSTEMMODE=0,0,1,0") and data from BMP280 sensor  --> store it in data_pack

2. Turnoff GPS and Enable LTE_M: ("AT\%XSYSTEMMODE=1,0,0,0") & use HTTP POST to post data_pack to my webserver 

3. Switch to NB-IoT: ("AT\%XSYSTEMMODE=0,1,0,0") & use HTTP POST to post data_pack to my webserver

Is it posiblie to do like that now?

I know: "The current modem firmware, v0.7.0-29-alpha, allows you to choose the system mode via command %XSYSTEMMODE, but it does not support them concurrently, meaning that you cannot have GPS + NB-IoT, or GPS + CAT M1, enabled simultaneously at this time." Håkon Alseth https://devzone.nordicsemi.com/f/nordic-q-a/48077/gps-http-post

I can switch: AT\%XSYSTEMMODE=0,0,1,0/AT\%XSYSTEMMODE=1,0,0,0/AT\%XSYSTEMMODE=0,1,0,0 but I couldn't POST data to my webserver.

Do you have any suggestions?

Thanks,

Regards, 

hng

[Håkon Alseth]

Hi hng,

 

I am very sorry for not seeing the last post in the linked case.

The system has a flaw when you accept an answer, then add a new reply, it will still mark the case as resolved, so I do not get a notification or state-change on that topic, unfortunately.

 

From the last reply, it seems that you are not able to successfully connect over NB-IoT in your area, as you do not get the Cell ID, MCC, MNC, and other registration information. You could try to ask your local network providers if there's a nb-iot coverage issue in your area.

Cat M1 still works fine, right?

 

Kind regards,

Håkon

[Hoang]

Dear Håkon Alseth

Thats ok Håkon. 

I verified the NB-IoT in Horten, Vestfold with iBasis: NO. Then, I used another sim card (telia), I got NB-IoT signal but no LTE-M. I will find someone else, can supply both LTE-M and NB-IoT. 

But, what do you think about my plan: 

I want to do: 

1. Enable and get GPS position ("AT\%XSYSTEMMODE=0,0,1,0") and data from BMP280 sensor  --> store it in data_pack

2. Turnoff GPS and Enable LTE_M: ("AT\%XSYSTEMMODE=1,0,0,0") & use HTTP POST to post data_pack to my webserver 

3. Switch to NB-IoT: ("AT\%XSYSTEMMODE=0,1,0,0") & use HTTP POST to post data_pack to my webserver

Is it possible to do like that now?

Regards,

hng

[Hoang]

as last time, I mentioned, I couldn't POST when I remove the option: 

# LTE link control
CONFIG_LTE_LINK_CONTROL=y

in prj.conf

[Håkon Alseth]

Hi,

 

You need to manually start the modem unless you have the LTE Link control library present. It's best just to leave that one enabled.

So, you have one SIM that does LTE M, and another that does NB-IoT.

If you use them both, you should be able to test all 3 scenario's, but not "on the same run".

 

I would still recommend that you contact the network provider and ask regarding coverage in your area.

 

Kind regards,

Håkon

[Hoang]

For example, with iBasis sim ( LTE_M). 

1. Enable and get GPS position ("AT\%XSYSTEMMODE=0,0,1,0") and data from BMP280 sensor  --> store it in data_pack

2. Turnoff GPS and Enable LTE_M: ("AT\%XSYSTEMMODE=1,0,0,0") & use HTTP POST to post data_pack to my webserver

Can we? I can't use GPS if I LTE link control library present.

[Håkon Alseth]

You should see the note in the top of the documentation here:

https://infocenter.nordicsemi.com/topic/ref_at_commands/REF/at_commands/mob_termination_ctrl_status/xsystemmode_set.html?cp=2_1_3_30_0

 

The CFUN=4 command corresponds to function lte_lc.c::lte_lc_offline()

Then switch the xsystemmode to your wanted mode, and you can call lte_lc.c::lte_lc_normal() to start up again.

 

Kind regards,

Håkon