nRF9160 LTE connection failure (at_client example)

[talmagro]

Hi all,

I have the nRF9160 DK and I've just tried the out of the box demo (asset_tracker) following all the steps, but it didn't work because it seems that iBasis SIM does not have LTE coverage in Valencia (Spain). Because of that, I "bought" a free Global IoT SIM card from Hologram (https://hologram.io/iot-sim-card/ ), because they supposedly have coverage in Spain. I received it, activated it and tried the out of the box connection, but still didn't worked. I guess it didn't work because as far as I know, if the DK wants to use data on the hologram network, I have to set the hologram's APN correctly. Is it possible to configure this parameter on the asset_tracker example of the SDK?

I also downloaded the at_client example code to the nRF9160  MCU trying to debug what was happening. When I connected the PC to the DK (with the Hologram SIM activated) using the LTE Link monitor app I followed these steps:

• I typed the AT command “AT+CFUN?” and I got:
• Then I typed the “AT+CFUN=1” as suggested and I obtained the same result.
• But If try to set the APN through an AT command (AT+CGDCONT=1,"IP","hologram") and then I type  “AT+CFUN?” to connect to a LTE network and turn on the modem, I get lots of messages through the terminal and the modem, UICC and PDN boxes of the nRF Connect GUI change to green color. So I guess both the modem and the SIM are working properly. However, the LTE box changes to red and yellow.

What could I do to solve this issue? Is it a problem of the hologram's IoT SIM? Thank you very much in advance.

Best regards,

Toni

[iBasis Tech Support]

Hi Toni,

We actually do have coverage over Movistar Spain for LTE-M.  Please refer to our coverage list  http://iot.ibasis.com/network-coverage/.  We are actively updating this list.  Please try using our eSIM again.                                                        Kind Regards, iBasis Tech Support

[talmagro]

Hi Bjørn Kvaale!

I successfully flashed the NB-IoT modem FW and these are the results I am getting while using the at_client example and the LTE Link monitor (I'm using Hologram's IoT SIM card):

• First of all I use the following AT commands: "AT+CGDCONT=1,"IP","hologram"", "AT+CFUN?" and "AT+CFUN=1".
• After that the modem turns on and I receive a bunch of messages. 
• Then the DK receives the following AT commands:: "%CESQ: 42,2", "+CEREG: 2,"0B09","07087D3F",9", "+CNEC_EMM: 15" and  "+CEREG: 4,"0B09","07087D3F",9". So it seems that it receives signal but it is not able to register to any network.
• After this I receive "%CESQ: 255,0" and no signal is received again.
• If I press the "Search network" button on the LTE Ling Monitor App I receive "+COPS: (1,"","","21401",9)" and "+COPS: 2". And then the Vodafone Spain Network appears with available Status on the App. But the LTE indicator is still in yellow/red color so I'm not registered on the network... (The other indicators (UART, Modem, UICC, PDN are green)).

Which could be the problem? What can I do to connect to the Vodafone Spain Network that is available?

Thanks in advance and best regards,

Toni

[Dominik Windhab]

Hi! I came across similar problems when connecting to NB-IoT here in Austria (A1 Telekom). It seems like I am able to register to the network after the first boot after I flashed the application. Then LTE Link Monitor says everything ok, but after a reset the DK I have the same issues you are describing. Did you find any solution or support for this problem?

[talmagro]

Hi! Actually I couldn't register to the net.. My DK is able to recognize the Vodafone Spain Network but it can't register to it. I'm still waiting for the support since I wasn't able to solve it...

[MIoT]

Hello, I'm Vicente, from Valencia too, there is something new with this topic, I'm with the same problem.
Best regards.
Saludos.