NB-IoT (Narrowband IoT)
Updated
NB-IoT is a narrowband cellular technology for IoT, standardised by 3GPP in Release 13. It uses a 180 kHz channel, offers deep indoor coverage and very low power use, but low data rates and limited support for moving devices.
In practice
NB-IoT fits static sensors that send a few bytes a day, such as meters in basements; it is a poor fit for trackers on the move or for firmware updates of several megabytes.