No LTE Connectivity

[Servo]

Hello All,

I recently started testing  an nRF9160 DK board. I was able to follow through all the instructions, registered on nRF cloud and successfully connected to LTE. But ever since, for some reason the board just refuses to connect to the network. I have tried resetting the board, I even added the board again on nRF cloud but to no avail.

Has anyone encountered something similar? Please help me solve this issue. (Note: I have only used 0.52 MB of the provided data)

Thanks in advance.

[Heidi]

Hi! 

From the logs it looks like you're not having an issue with the LTE connection, but rather the connection to nRF Cloud. This is most likely because there is something wrong with the nRF Connect for Cloud certificates on the modem. To re-provision the certificates, you can follow this tutorial. Mare sure to do everything in the correct order. However, you don't really need the connection to nRF Cloud to test the signal quality.

You can use either the AT Client sample or the Serial LTE Modem application to do this. Use AT commands to connect to the LTE network.

You can use +CESQ to read out [rsrq, rsrp], but it doesn't look like we have support for reading out RSSI or BER. I've put in a request with the modem FW team to see if they have any suggestions are a possible work-around for this.

Best regards,

Heidi

[Heidi]

UPDATE: Bit Error Ratio isn't supported in LTE, which is why we don't have support for it. RSSI can be calculated from the RSRQ and RSRP values like this:

RSSI = 10log(N) + RSRP - RSRQ. 

N is Resource Blocks and is 6 for LTE M1.