NB-IoT

The question every IoTITermIoT (Internet of Things)The IoT (Internet of Things) is the network of physical objects with sensors, software and connectivity that collect and exchange data and act autonomously.View profile architect asks on reaching LPWANLTermLPWANLPWAN (Low-Power Wide-Area Network) is a category of long-range, low-power wireless networks for IoT. It includes LoRaWAN, NB-IoT and LTE-M.View profile is direct: LoRaWANProtocolLoRaWANOpen long-range, low-power LPWANView profile, or what NB-IoT is exactly and what it gives you over unlicensed spectrum. Licensed spectrum, the operator's network, coverage wherever that operator has rolled NB-IoT out, a real SLA and a recurring bill, against private LoRaWAN with no connectivity cost. This article is the starting point for making that decision with data. The full guide, with the decision criteria and the frequently asked questions, is in What NB-IoT is and when to use it.

Executive summary

• NB-IoT (Narrowband IoT) is a cellular LPWAN radio access technology specified by the 3GPP in Release 13 (June 2016) and evolved in R14, R15 and R16 (accessed: 2026-05).
• It occupies a 200 kHz channel (a single LTE resource block) and operates in the operator's licensed spectrum, on sub-1 GHz LTE bands (B1, B3, B8, B20, B28, among others).
• Maximum data rate: ~26 kbps downlink, ~20 kbps uplink (R13). Enough for periodic telemetry; not suitable for streaming.
• Battery life: 10+ years with periodic transmissions and PSM (Power Saving Mode) enabled. The modules draw under 10 µA in deep sleep.
• Coverage: improved indoor penetration via an MCL (Maximum Coupling Loss) of 164 dB, better than standard LTE (~140 dB) and comparable to LoRaWAN SF12.
• The GSMA has published deployment guides and keeps a Mobile IoT deployment map listing the NB-IoT networks live in each country.
• Don't use it when: you need fewer than 1 message/hour (LoRaWAN is cheaper), you operate in areas with no cellular coverage, you have zero connectivity budget, or you need high mobility with frequent handover.

What NB-IoT is and what it's for

NB-IoT is the cellular ecosystem's answer to the rise of unlicensed LPWAN networks. Before 2016, an IoT device that needed nationwide indoor coverage — a water meter in a building basement, an asset tracker in a shipping container — had two options: GPRS (expensive, high power draw, not designed for IoT) or LoRaWAN (private coverage, no SLA).

The 3GPP designed NB-IoT to cover that gap using the resources of the existing LTE network. Operators can enable NB-IoT on their LTE infrastructure through a software upgrade — they need no new spectrum and no new tower infrastructure.

NB-IoT is part of the LPWAN connectivity IoT ecosystem, alongside LoRaWAN and SigfoxSProtocolSigfoxUltra-narrowband LPWAN for tiny messagesView profile. You can see the full picture of IoT protocols at Plataforma IoT.

How NB-IoT works

Deployment modes

The operator can deploy NB-IoT in three ways:

In all three cases, the NB-IoT device sees exactly 200 kHz of bandwidth. The eNB (LTE antenna) adds NB-IoT support as just another scheduler resource.

PSM and eDRX: the key to battery life

The 10+ years of battery life don't come from the radio — they come from the power-saving modes standardized in 3GPP:

PSM (Power Saving Mode): the device negotiates an active time (T3324, e.g. 10 s) and a deep-sleep time (T3412, e.g. 12 hours) with the network. During sleep, the device is effectively off — the network can't reach it. Ideal for sensors with periodic reporting (a water meter that transmits daily).

eDRX (extended Discontinuous Reception): longer listening cycles than standard LTE DRX. The device "wakes up" every N seconds to check for pending messages from the server. It allows some bidirectional latency without continuous power draw.

PSM timeline:
|--Transmit--|--T3324 active--|----------------T3412 sleep (hours)----------------|--Transmit--|
             ↑ server can send during T3324

Network architecture

[NB-IoT device]
        ↓ (200 kHz radio)
[Operator's eNB / LTE base station]
        ↓ (S1-U / control plane CIoT optimization)
[EPC: MME, SGW, PGW]
        ↓ (IP / NIDD)
[IoT server / platform]

The data plane can be standard IP (UDP/CoAPProtocolCoAPCoAP (RFC 7252) brings GET/POST/PUT/DELETE to devices with 8 KB of RAM over UDP. How Observe and DTLS work, and when to pick it over MQTT.View profile, MQTTProtocolMQTTThe standard pub/sub protocol of IoTView profile over TCP) or NIDD (Non-IP Data Delivery), where data is carried directly over the signaling plane with no IP address — reducing overhead for small payloads.

Main frequency bands

NB-IoT operates on the same sub-1 GHz bands as LTE, which offer the best indoor penetration:

In Spain, Movistar, Orange and Vodafone offer NB-IoT on bands B20 and B8 with nationwide coverage. Verify coverage by municipality on each operator's portals before designing.

Real-world use cases

NB-IoT stands out where guaranteed coverage, long battery life and low data volume come together:

Asset tracking is one of the typical uses: equipment that moves little, reports a few times a day and needs coverage beyond your own network.

When NOT to use NB-IoT

Being direct about NB-IoT's limits saves money:

If message density is very low and you don't need an operator SLA, LoRaWAN is cheaper. A LoRaWAN node transmitting every 6 hours can cost nothing in connectivity on a network like The Things Network or Helium. NB-IoT has a monthly cost per SIM — irrelevant at scale, significant in pilots or projects with under 1,000 nodes.

Without cellular coverage, NB-IoT doesn't work. In remote rural areas of Spain, sub-1 GHz LTE coverage can fail where LoRaWAN with a private gateway does reach.

For high mobility (vehicles, drones, pedestrians on the move), LTE-M is better. NB-IoT doesn't support cell handover while moving — mobile devices lose their connection when crossing cells. LTE-MLProtocolLTE-MCellular IoT with mobility and voiceView profile (Cat-M1), also part of 3GPP Release 13, has handover and supports VoLTE, designed precisely for mobile trackers.

For frequent data (more than 1 message/minute), NB-IoT is costly. The radio duty cycle and the control-plane limitations make it inefficient for continuous polling. MQTT over LTE-M or conventional 4G is a better fit.

If you need latency under 1 second for real-time actuation, NB-IoT with PSM enabled isn't compatible — the device may be asleep for 12 hours.

NB-IoT vs LoRaWAN: when to choose each

The detailed comparison is in LoRaWAN vs NB-IoT. The LoRaWAN article covers the unlicensed technology in depth.

Getting started: an NB-IoT module with AT commands

The most widely used NB-IoT modules (Quectel BC660K, SIMCom SIM7020E, u-bloxCompanyu-bloxPositioning (GNSS) and cellular communication modulesView profile SARA-R410M) expose a UART interface with standard 3GPP AT commands plus vendor extensions.

1. Basic network connection

# Verify the module
AT
# OK

# Check the IMEI
AT+CGSN
# 357520080678555

# Set the operator's APN
AT+CGDCONT=1,"IP","iot.movistar.es"

# Activate the PDP context
AT+CGACT=1,1

# Verify the assigned IP
AT+CGPADDR=1
# +CGPADDR: 1,10.128.45.22

2. Send a UDP datagram (CoAP or raw payload)

# Open a UDP socket
AT+NSOCR="DGRAM",17,0,1
# 0 (socket ID)

# Send 4 bytes to the server on port 5683 (CoAP)
AT+NSOST=0,"93.184.216.34",5683,4,"41010000"

# Close the socket
AT+NSOCL=0

3. Enable PSM (maximum battery life)

# PSM: T3412=12 hours, T3324=10 seconds
# Timer value encoding per 3GPP TS 24.008
AT+CPSMS=1,,,,"00100110","00000001"

# Verify PSM status
AT+CPSMS?
# +CPSMS: 1,,,,"00100110","00000001"

After the transmission, the module enters PSM automatically when T3324 expires. Consumption drops from ~200 mA (TX) to under 10 µA.

Primary sources

• 3GPP — NB-IoT standardization complete — official 3GPP note (accessed: 2026-05)
• GSMA — NB-IoT Deployment Guide v2 — industrial deployment guide (accessed: 2026-05)
• 3GPP — NarrowBand IOT overview — 3GPP technical overview (accessed: 2026-05)