Low-Power Wide-Area Networks (NB-IoT, eMTC, LoRa)
What the exam tests
NB-IoT, eMTC (LTE-M), and LoRa: spectrum, data rate, power saving, mobility, and deployment.
Core rules
- NB-IoT: licensed LTE spectrum, 180 kHz bandwidth, extended coverage (about +20 dB), very low rate, PSM and eDRX for years of battery; no voice and limited mobility/handover.
- eMTC: licensed, 1.4 MHz, higher rate (about 1 Mbps), supports VoLTE and handover, better for mobile or voice-adjacent use.
- LoRa: unlicensed ISM, chirp spread spectrum, long range at low rate; LoRaWAN defines classes A (baseline), B (beacon), C (continuous receive); gateways forward to a network server; duty-cycle limits apply.
- Choose by licensing, mobility, payload, latency, and battery.
Worked example
A water utility needs 10-year battery meters sending 100 bytes daily underground. NB-IoT fits: licensed spectrum, deep coverage, PSM, low rate. A fleet tracker needs handover and higher uplink; eMTC fits. A campus with its own gateways and no cellular fees could use LoRa, accepting duty-cycle and best-effort downlink.
Traps
- Claiming NB-IoT supports voice or seamless handover; it does not.
- Treating LoRa as licensed or guaranteed; ISM duty cycle and interference matter.
- Confusing eMTC with NB-IoT coverage; NB-IoT generally wins on deep coverage, eMTC on rate and mobility.