NRF9161 signal strength measurment seems to break TCP/IP connection - any solution/suggestion?

[marsal]

Hi,

based on the previous struggle with data transfer drops with nrf9161 (NRF9161 based LTE-M tracker data drops while moving – can it be optimized? ) we came after the cooperation with Vodafone MNO to the situation, that (at certain test place) connection does not drop and the connected handover works smoothly.

However, a new issue has occured: as expected, the network forces the signal strength measurement to send MeasurementReport. But before this resport is sent, TCP/IP sometimes drops as (if week signal and/or more neighbors, probably) the measurement takes longer time then TCP/IP connection in the given case can survive.

In case of interest, here is a Wireshark modem trace: https://e.pcloud.link/publink/show?code=XZMSvUZyf7WCFoVYn4t5cLhMDzUJjaq6tj7 (and here the original modem trace: https://e.pcloud.link/publink/show?code=XZlSvUZAxlk66k8RiRYM1gLQbu3KBkWWl47), look at line 1392, for example, where the connection starts to stuck. In the modem trace, there are also connection breaks, but this trace was not taken at the test site, so this may be considered as non relevant.

Is there any option how to "save" TCP/IP transfer during signal strength measurement with NRF9161?

Thank you

Martin

[dejans]

Hi Martin,

In case of interest, here is a Wireshark modem trace: https://e.pcloud.link/publink/show?code=XZMSvUZyf7WCFoVYn4t5cLhMDzUJjaq6tj7 (and here the original modem trace: https://e.pcloud.link/publink/show?code=XZlSvUZAxlk66k8RiRYM1gLQbu3KBkWWl47), look at line 1392, for example, where the connection starts to stuck. In the modem trace, there are also connection breaks, but this trace was not taken at the test site, so this may be considered as non relevant.

Can you provide more information about signal strength measurement?
What do you refer to as MeasurementReport? Where is this MeasurementReport sent?

In case of interest, here is a Wireshark modem trace: https://e.pcloud.link/publink/show?code=XZMSvUZyf7WCFoVYn4t5cLhMDzUJjaq6tj7 (and here the original modem trace: https://e.pcloud.link/publink/show?code=XZlSvUZAxlk66k8RiRYM1gLQbu3KBkWWl47), look at line 1392, for example, where the connection starts to stuck. In the modem trace, there are also connection breaks, but this trace was not taken at the test site, so this may be considered as non relevant.

I am not able to open your links. Can you please upload modem trace files directly to this ticket?

Best regards,
Dejan

[marsal]

Hi,

could you kindly try to download the trace outside the corporate network? I guess the corporate firewall may block it.
By MeasurementReport I mean an RRC message MeasurementReport sent by modem to the network per network request. In the trace, there is signal strength available.

Edit: acutally, the question may by simple: Does the measurement of the signal strengths in nrf9161 cause TCP/IP data transmit drop?

Thanks

Martin

[dejans]

Hi Martin,

There are very low values of RSRP. It looks like the signal is very weak. It seems that your device is almost at the edge of coverage.
Is your device experiencing slow data transmission, data loss or complete connection loss? How does your device recover from such situation?
Have you done neighbor cell measurements?

Best regards,
Dejan