LTE Link monitor

[Aleksa]

Hi everyone,

I am getting start with the GPS and LTE connections on your nrf9160dk platform. I have tried all of the samples I was able to find but I get some weird results more often then not. I've seen that the LTE Link Monitor in the nrfconnect app could be useful to play around with the board. However I am unable to find any information about how to get started with the LTE Link Monitor? 

I am not sure what should I flash to the device, in order to get it working. Right now I have flashed one of your samples(multicell location - doesn't really work for me, it gives "CELL ID = -1"), and I've updated the modem firmware through the programmer from the nrfconnect. But when I connect via LTE Link Monitor, and reset the board, nothing shows up in the terminal except for the AT+CFUN=?.

Any help would be appreciated. I'd prefer getting LTE Link Monitor working, but some advices on the GPS/AGPS/MCELL samples are welcome as well. 

Cheers,

Aleksa

[Aleksa]

Hi Marte,

I was able to get going with AGPS and GPS with iBasis, but the multicell is still troubling me.

Well I've ran the code from the segger ide, and I've used LTE Link Monitor to see if it has LTE connection. It didn't have one. Weird thing with the example is that it uses only lte_connect(), instead of lte_lc_init_and_connect(). Not sure if that could be an issue.

Best Regards,

Aleksa

[Marte Myrvold]

Hi Aleksa,

The multicell sample use lte_lc_init_and_connect_async() instead of lte_lc_init_and_connect(). You can see this in the function lte_connect(), which is a function in main.c, and specific for this sample. The difference between lte_lc_init_and_connect() and lte_lc_init_and_connect_async() is that the latter, async, is non-blocking. This means that it does not block until a connection is established (or has timed out), which lte_lc_init_and_connect does. 

Could you please post the log output you are getting from the multicell sample? 

Best regards,

Marte

[Aleksa]

Hi Marta,

This is the complete output:

*** Booting Zephyr OS build v2.6.0-rc1-ncs1-3-g0944459b5b62  ***
[00:00:00.215,789] <inf> multicell_location_sample: Multicell location sample has started
[00:00:00.225,067] <inf> multicell_location: A certificate is already provisioned to sec tag 177
[00:00:00.274,627] <inf> multicell_location_sample: Connecting to LTE network, this may take several minutes...
[00:01:08.908,203] <inf> multicell_location_sample: LTE cell changed: Cell ID: -1, Tracking area: -1
[00:01:08.908,721] <inf> multicell_location_sample: Cell change triggered start of cell measurements
[00:01:08.911,346] <inf> multicell_location_sample: Neighbor cell measurements received
[00:05:33.943,481] <inf> multicell_location_sample: Button 1 pressed, starting cell measurements
[00:05:33.952,148] <inf> multicell_location_sample: Neighbor cell measurements received

I've pressed the button 1 once. When I log in to the nrf cloud, I see that the device is disconnected. I've configured the api key and set nrf_cloud=y in the prj.conf. I've seen in the project readme that only one cell is usable when going with nrf_cloud, and that here and skyhook can use multiple cells. Not sure why is that the case and if I can't use nrf_cloud when trying to get MCELL readings.  

This is what I get when I change from async connection to the blocking lte_lc_init_and_connect():

 

*** Booting Zephyr OS build v2.6.0-rc1-ncs1-3-g0944459b5b62  ***
[00:00:00.216,461] <inf> multicell_location_sample: Multicell location sample has started
[00:00:00.225,738] <inf> multicell_location: A certificate is already provisioned to sec tag 177
[00:00:00.233,764] <inf> multicell_location_sample: lte_lc_init and connect this may take a while
[00:10:00.282,257] <inf> lte_lc: Network connection attempt timed out
[00:10:00.291,961] <inf> lte_lc: Using fallback network mode
[00:20:00.324,432] <inf> lte_lc: Network connection attempt timed out
[00:20:00.324,829] <err> multicell_location_sample: Modem could not be configured, error: -116
[00:20:00.325,317] <err> multicell_location_sample: Failed to connect to LTE network, error: -116

I've removed k_sem_take(&lte_connected, K_FOREVER); and just replaced the async function with the blocking one.

Cheers,

Aleksa

[Aleksa]

Woohoo!

Thanks for a fantastic support, I was able to get it to work I think. In case that someone from a country that seems to have issues with LTE stops by, this is how it worked for me:

//lte_lc_init_and_connect_async(lte_handler);
//Replace the function above with the following:
lte_lc_init();
lte_lc_system_mode_set(LTE_LC_SYSTEM_MODE_NBIOT, LTE_LC_SYSTEM_MODE_PREFER_NBIOT);
lte_lc_connect_async(lte_handler);

Seems like this was all I've needed. 

Best Regards,

Aleksa