NB-IoT

NB-IoT is a narrowband cellular IoT technology standardised in 3GPP Release 13 (2016). Its 180 kHz carrier can be deployed in three ways: inside an LTE carrier (in-band), in the LTE guard band, or on its own, for example on a former GSM frequency (standalone). Operators usually add it to existing base stations through a software upgrade. On the device side a SIM card or eSIM is all that is needed, and no gateway has to be installed.

Coverage is its main advantage. With a 164 dB maximum coupling loss target it offers roughly 20 dB better coverage than GSM, reaching meters in basements or inside manholes. In weak signal conditions messages are repeated, which extends coverage at the cost of energy and latency. Data rates are in the tens of kbit/s. Voice is not supported and it is not intended for devices on the move.

Two mechanisms save energy. In PSM (Power Saving Mode) the device stays registered on the network but switches its radio off completely, waking when a configured timer expires. eDRX lets the device listen at extended intervals, balancing reachability against battery life. For a well-configured device sending a few messages a day, battery life of up to 10 years is targeted. Within 3GPP, NB-IoT and LTE-M are recognised as technologies that meet 5G massive IoT (mMTC) requirements.

Compared with LoRaWAN, NB-IoT needs no infrastructure build-out, runs in licensed spectrum with low interference risk and comes with operator service assurance. On the other hand it involves a per-device subscription, dependence on operator coverage and generally higher module energy consumption. In Türkiye, NB-IoT is offered by mobile operators, and actual coverage should be verified at every site with RSRP and SINR measurements before deployment.