What is NB-IoT
Quick definition
NB-IoT (Narrowband IoT) is a 4G/5G LPWA technology optimized for small messages from static, multi-year battery devices. It runs in a 200 kHz sub-band and prioritizes deep coverage and extreme power efficiency over throughput.
Where it is the right choice
Static sensors in basements and pits (water, gas, electricity meters), parking, remote environmental sensors, smart lighting. Anywhere mobility and latency do not matter and you want 5-10 years of battery.
Real limitations
No handover (change cell, lose session), 1-10 second latency, tens of kbps throughput, and not every network supports it worldwide. Indoor coverage is excellent but cross-region coverage is uneven.
FAQ
How long can an NB-IoT sensor battery last?+
With aggressive PSM and a couple of messages a day, a lithium AA can hold 5-10 years. Key is minimizing wakeups and using PSM aggressively.
Can I migrate from 2G to NB-IoT?+
Yes, it is the natural path for legacy 2G smart metering and static sensors. Caveat: check carrier coverage at the exact site before ordering hardware.
Related terms
What is LTE-M
LTE-M (also LTE Cat-M1) is an LTE variant designed for IoT: moderate bandwidth (up to 1 Mbps), very low power, voice support, and real cell-to-cell mobility. It is the sweet spot between NB-IoT (cheaper but static) and Cat-1 (faster but power-hungry).
What is LTE Cat-1
LTE Cat-1 is the LTE device category targeted at general-purpose IoT: up to 10 Mbps down, 5 Mbps up, voice support, and works on any 4G network worldwide. Its Cat-1 bis variant runs on a single antenna, cutting hardware cost. It is the workhorse behind POS terminals, alarms, gateways, and low-bitrate CCTV.
What are PSM and eDRX
PSM (Power Saving Mode) and eDRX (extended Discontinuous Reception) are 3GPP-defined mechanisms that let a cellular IoT device draw microamps while idle. PSM turns the modem off between long windows (up to days); eDRX spaces paging listening in short intervals (seconds to minutes) without losing network registration.