No LTE Connectivity

RE: No LTE Connectivity

Heidi — Wed, 24 Jun 2020 09:12:35 GMT

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.

RE: No LTE Connectivity

Heidi — Tue, 23 Jun 2020 10:45:52 GMT

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

RE: No LTE Connectivity

Servo — Mon, 22 Jun 2020 20:01:31 GMT

Hello Heidi,

I was able to flash the asset tracker and it is now connected to the network. But for some reason the connection is very unstable and keeps disconnecting every few seconds. I have attached the log here.

We are mulling on using the Nordic nRF9160 lte board as the default for communication in our portable device. As such, I am trying to conduct a test on the signal quality, specifically [rssi, ber] values for different scenarios. Could you also help with the same if possible. I have successfully conducted similar tests on other lte devices using putty. It is imperative that I conduct a similar test on nRF9160 to compare results.

Please advise.

Thank You

Sincerely,

Sarvjitdevzone.nordicsemi.com/.../2020_2D00_06_2D00_22T19_5F00_44_5F00_16.154Z_2D00_log.txt

RE: No LTE Connectivity

Heidi — Thu, 18 Jun 2020 07:42:29 GMT

Hi, this log doesn't really contain any information. (Side note, the command is AT+CEREG, not AT+CREG)

What version of the DK do you have?

It looks like the application does not even begin to run, which is strange. Could you try flashing the Asset Tracker application again?

For LTE-M: devzone.nordicsemi.com/.../nrf9160dk_5F00_asset_5F00_tracker_5F00_ltem_5F00_debug_5F00_2020_2D00_04_2D00_29_5F00_bc7ade8b.hex

For NB-IoT: devzone.nordicsemi.com/.../nrf9160dk_5F00_asset_5F00_tracker_5F00_nbiot_5F00_debug_5F00_2020_2D00_04_2D00_29_5F00_bc7ade8b.hex

RE: No LTE Connectivity

Servo — Wed, 17 Jun 2020 19:26:13 GMT

Hello Heidi,

Apologies for the late reply. I got sidelined with other tasks at hand. Please find here the latest log from today. Hope this will help clear up the issue.

Sincerely,

Sarvjitdevzone.nordicsemi.com/.../2020_2D00_06_2D00_17T17_5F00_46_5F00_23.864Z_2D00_log.txt

RE: No LTE Connectivity

Servo — Wed, 03 Jun 2020 23:26:28 GMT

Thanks Heidi. I have tried waiting for even an hour but it does not connect I will send the log by tomorrow.

Thank you

Sincerely,

Sarvjit

RE: No LTE Connectivity

Heidi — Tue, 02 Jun 2020 12:26:50 GMT

Hi!

For us to investigate this issue, we will need the log file from LTE Link Monitor (an application available in nRF Connect for Desktop) while you're trying to connect. Please let the device try to connect for at least 10 minutes and then press the button below to get the full log in .txt format, then attach it in your new comment.

Best regards,

Heidi