AWS IoT LTE Connection Handling

[jake11212]

Hello,

I am working with the 9160DK and the AWS IoT sample in NRF Connect 1.8.0.  The app is usually able to connect to LTE but sometimes it gets stuck and never connects even after 10+ minutes.  I don't think this is a connection issue as I can reset the development kit and it usually reconnects in about 15 seconds or less.  I'm not getting any errors when this happens so I was wondering if there were any methods for troubleshooting what might be going on in these situations, and if there were methods for handling this error.

I was considering a timer that resets the DK automatically if LTE doesn't establish a connection for more than a certain amount of time, but this felt like a brute force method and I was looking for a better solution.

Thanks!

[Hakon]

Hello,

I'm not getting any errors when this happens so I was wondering if there were any methods for troubleshooting what might be going on in these situations, and if there were methods for handling this error.

It's hard to say what's going on without any logs or modem trace.

I was considering a timer that resets the DK automatically if LTE doesn't establish a connection for more than a certain amount of time, but this felt like a brute force method and I was looking for a better solution.

You can consider changing the timeout interval CONFIG_LTE_NETWORK_TIMEOUT.

[jake11212]

I see that it's possible to add the LTE_NETWORK_TIMEOUT but is there any documentation for generating that timeout handler or is there some default behavior that takes place upon timeout?  I wasn't able to find any documentation on what happens after the timeout occurs.

[Hakon]

Yeah, there is no "timeout handler". When calling lte_lc_connect() or lte_lc_init_and_connect() (not async), it will block until it finishes the scan or it times out. The timeout is determined by LTE_NETWORK_TIMEOUT. If CONFIG_LTE_NETWORK_USE_FALLBACK=y, it will try both LTE-M and NB-IoT, both for LTE_NETWORK_TIMEOUT seconds before returning.

[jake11212]

So then there is no error/status when the timeout period ends?  So I would just need to make an error handler that checks after the connection attempt if connection is active, and if it isn't add an error handler and assume that the connection failed because of the timeout?

[Hakon]

Yes, that seems like a decent sloution.