nRF9160 Modem transition to Idle state

[Abdullah Javed]

Hi,
we are using custom PCB with nRF9160.

we are writing a firmware for radio test lab. We are using LTE asynchronous in our firmware and LTE-M mode. We want the modem to stay connected to network for at-least 30 minutes. But we are facing an issue, where the modem goes to idle state after some time, and goes to connected state again, and then repeats this behavior as you can see in the image below. We believe this is due to the Network Inactivity timer

Our goal is to ensure that the modem remains connected to the network without entering the idle state during the test, maintaining a continuous connection. We do not want the modem to transition into idle mode due to inactivity.

We would like to handle this behavior at the firmware level. Is it possible to configure the modem to stay connected at all times and avoid transitioning into the idle state? If so, could you provide guidance on how we can modify the firmware or settings to achieve this? Is there any configuration or function in LTE Link controller API?

Thank you for your support.

Best regards,
Abdullah

[dejans]

Hi Abdullah,

This blog specifies that it is the network who determines RRC Inactivity Timer value and UE cannot negotiate that. 

Is any activity allowed for these 30 minutes? Does your firmware allow that UE receives any messages or send any data to stay connected?

Do you use eDRX or PSM?

Best regards,
Dejan

[Abdullah Javed]

Hi Dejan,

Thanks for the answer.
We are not using eDRX or PSM mode; they are not enabled in our firmware.
And yes, we can transmit or receive any data, but will that keep RRC active for the entire 30 minutes of testing?
What do you suggest as an activity that could best address this issue?

Thanks and regards,
Abdullah