Hi! We are currently testing our custom device using the nrf9160 modem. Our use case is for an ultralow power IoT device that connects to the Internet each 30 minutes to send some data and then goes back to sleep. We don’t use PSM, when the device goes back to sleep, we disconnect from the cloud and set the modem to flight mode. The device will be in a place with no coverage (a maritime container) for days or weeks, in which the device will be in “hibernation mode”, trying to connect to LTE-M each 4 hours.
We have seen that after the first connection, the device connects to the LTE-M network in less than 5 seconds but before that, the first connection takes a long time, around two minutes.
We are using the command AT+CGDCONT before every connection to set the APN hoping that it will decrease the time it takes for that first connection, but it doesn’t make a lot of difference. The device travels around the world, so we cannot lock the LTE-M bands nor the country.
Why does the first connection take a long time and the rest doesn’t? What are the best practices to reduce the time of that first connection? Are there any other AT commands that we can use to reduce that time?
Thank you and best regards
