nrf9160 Band Selection Algorithm

[Musa.A]

We are wondering how nrf9160 modem decides which band to use when there are multiple bands available (LTE CAT NB) and there isn't any apllied band lock from the software side. In our use case, although there are 2 bands available for the device, it selects mostly the one which has worse RSSI. Is it possible to make one band preferable without locking the other band?

Best Regards,
Musa

[Hakon]

I have asked internally for details on the algorithm. I will let you know when I have more information.

[Hakon]

Here's the answer I received;

"Device has selected the cell, which has worse RSSI at some point of time when it has been better, or network configuration for LTE idle mode mobility has directed device to it.

With current implementation modem will prefer the most recent cell/band where it has been in service and this means it will more likely select that same cell always again after boot. Device will stay there unless network's idle mode mobility configuration directs it to that cell on other band. Please note that network may apply an offset to idle mode mobility between cells, this offset may keep the device on current cell even though there would be stronger cell from the same network on other band."