Cannot connect to LTE after trying to disconnect/reconnect 30 times

[jgv_sl_bolt]

Hello,

I came across a very consistent bug that occurs on the nRF9160DK and a custom board with an nRF9160.

Basically, if you try to send the AT commands "AT+CFUN=1" and "AT+CFUN=4" 30 times, it cannot establish a registered LTE connection and searches perpetually. Before the 30th time, it is able to register a connection properly:

But after the 30th time:

You have to reset the board for it to work again.

Does anyone have an idea to why this happens? And why 30 times?

[Sigurd]

Hi,

This is the GSMA specified Radio Policy Manager (RPM) feature which is blocking the ATTACH command. RPM is used for protecting the network from excessive signalling loads in various scenarios. In this case default value 30 is used for PDP Context Activation Requests (TS.34_8.2.4_REQ_010, See page 43 in this pdf)

Edit: There is a bug in modem fw v1.0.x were the PDP Context Activation Requests counter is not reset after 1 hours. This is fixed in modem fw v1.1.0

[sheldon_b]

Is there a way to know that you have been throttled other than preventative measures? Waiting for the registration to timeout is very energy intense.