Narrow Band LTE (NB-LTE) is a variant of Long Term Evolution (LTE) for a cellular Internet of Things (CIoT). NB-LTE is optimized for the narrowband transmission of small data packets and is suitable as a low power WAN (LPWAN) for extremely energy-efficient M2M communication
. This is particularly important because it allows a long battery life to be achieved. This is said to be 10 years. NB-LTE offers several improvements over LTE M2M (LTE-M). Like this, it operates in the sub-GHz range between 700 MHz and 900 MHz. The transmission bandwidth is only 200 kHz, compared to LTE-M's 1.4 MHz. The transmission rates of NB-LTE are 200 kbit/s in the downlink and 144 kbit/s in the uplink
. Thereceive sensitivity
, and the transmit and receive level budget is about 20 dB higher than that of LTE-M. Various methods contribute to energy efficiency and to extending battery life. One of these is the Power Saving Mode (PSM), in which a timer determines how long the terminal can be reached for mobile transmissions. The end device triggers the timer as soon as it goes into sleep mode. The mobile device then switches to power saving mode. In this state, the mobile device cannot be reached. It remains in this state until it is requested to perform an action via a Mobile Originated (MO) command.