What Is NB-IoT? How Narrowband IoT Works and When to Use It

NB-IoTProtocolNB-IoT3GPP-standardized cellular LPWAN — carrier coverageView profile (Narrowband 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) is a cellular low-power wide-area (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) technology that 3GPP standardized in Release 13 in 2016. It runs on mobile operators' licensed LTE spectrum in a slice about 200 kHz wide and is built for stationary, battery-powered devices that send small messages, often from basements, pits, and other places with weak signal.

Picture a water utility that wants a reading every few hours from meters sitting in concrete pits under the sidewalk. There's no power outlet, Wi-Fi doesn't reach, and nobody wants a gateway on every block. Each reading is a few dozen bytes, but the battery has to last for years. That is the job narrowband IoT was designed for.

This guide covers how it works, how it compares with LTE-MLProtocolLTE-MCellular IoT with mobility and voiceView profile, LoRaWANProtocolLoRaWANOpen long-range, low-power LPWANView profile, and SigfoxSProtocolSigfoxUltra-narrowband LPWAN for tiny messagesView profile, which operators offer it in the US, Mexico, and Spain, and what to check before you buy modules and SIMs. For the head-to-head with LoRaWAN only, read LoRaWAN vs NB-IoT; for a compact spec sheet, see the NB-IoT protocol page.

What Is NB-IoT (Narrowband IoT)?

NB-IoT, short for Narrowband Internet of Things, is one of three IoT technologies 3GPP added in Release 13, alongside LTE-M and EC-GSM-IoT. 3GPP completed the standard in June 2016 as part of LTE Advanced Pro.

What sets it apart from LoRaWAN or Sigfox is the spectrum. It runs on licensed frequencies that mobile operators already hold, on their existing LTE networks. You don't install gateways: you buy a SIM and a data plan, and the operator runs the network.

The design targets, summarized in ITU training material on 3GPP IoT standards, explain where it fits:

• A maximum coupling loss of 164 dB, 20 dB more than GPRS (144 dB). That margin is what gets a signal into basements and meter pits.
• About 10 years on a 5 Wh battery, depending on traffic and coverage.
• At least 50,000 devices per cell.
• Cheaper devices than LTE-M, in exchange for lower data rates, less mobility support, and simpler protocols.

It is also part of 5G. 3GPP included NB-IoT and LTE-M (eMTC) as components of its IMT-2020 submission to the ITU, even though both run on LTE networks today.

How NB-IoT Works

Three Deployment Modes

An operator can place a carrier in three ways. In-band, it uses resource blocks inside a normal LTE carrier; each carrier occupies 180 kHz, the width of one LTE resource block. Guard-band, it uses unused blocks in the guard band at the edge of an LTE carrier. Standalone, it gets its own spectrum, for example a carrier freed up from GSM.

The operator chooses the mode, not your device. T-Mobile, for instance, launched its nationwide network in July 2018 in the guard bands of its LTE spectrum.

PSM and eDRX: How NB-IoT Devices Sleep for Years

Most of the energy goes into staying reachable, not into sending data. Two features cut that cost.

Power Saving Mode (PSM), which comes from 3GPP's Release 12 work, keeps the device registered on the network with its radio off. It can't receive anything in PSM, but it doesn't have to attach again when it wakes up. The datasheet of the Quectel BC660K-GL, a current module, specifies 800 nA in PSM.

Extended discontinuous reception (eDRX) stretches the time between checks for incoming messages. In idle mode, eDRX cycles go up to about three hours on NB-IoT and about 44 minutes on LTE-M.

A typical cycle: wake up, send a reading, keep a short listening window for commands, go back to PSM.

The trade-off is reachability. A water meter that reports once a day doesn't care; a smart lock that must open within seconds does. The device requests PSM and eDRX timers and the network decides what to grant, so measure the values you actually get before you estimate battery life.

Coverage Enhancement Through Repetition

Deep indoor coverage comes from repeating each transmission. Each repetition can be decoded on its own, and the receiver combines them: up to 2,048 repetitions on the downlink and 128 on the uplink.

The price is speed and energy. At the highest repetition levels, the uplink falls to roughly 20 bits per second, which lets the link work at close to 170 dB of coupling loss. Two identical meters can end up with very different battery lives if one sits in a street cabinet and the other two floors underground, so size the battery for your worst site.

Data Rates and Latency

NB-IoT is half duplex and built for small, infrequent messages. Release 13 devices are Cat NB1. Release 14 added lower power consumption and latency, positioning, multicast, and mobility improvements, and its devices are sold as Cat NB2. The BC660K-GL, a Cat NB2 module, lists peaks of 127 kbps down and 158.8 kbps up with multi-tone transmission. Real throughput drops when coverage forces repetitions.

Latency follows the same logic. At the edge of coverage one message can take many seconds, and a device in PSM can't be reached until it wakes. Verizon sums up the right workload: delay-tolerant, event-triggered, simple stationary sensors that transmit rarely and don't need connected mobility. That's why operators point moving assets to LTE-M.

IP, Non-IP, and Application Protocols

The link carries IP traffic (UDP or TCP) and, where the network supports it, Non-IP Data Delivery (NIDD), which Verizon offers. 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 and LwM2M over UDP suit short, sparse exchanges. MQTTProtocolMQTTThe standard pub/sub protocol of IoTView profile runs over TCP, usually with TLS, and works well if you keep payloads compact and don't reconnect more often than you report, since every new connection costs handshakes and airtime.

NB-IoT vs LTE-M vs LoRaWAN vs Sigfox

All four are low-power wide-area options. They differ in who owns the spectrum and who runs the network.

NB-IoT vs LTE-M

Both are 3GPP standards on the same operator networks. LTE-M uses a 1.4 MHz channel, reaches about 1 Mbps, and T-Mobile positions it for devices in motion, over-the-air updates, and voice. Telcel in Mexico splits uses the same way: NB-IoT for smart meters, gas and liquid flow, building automation, street lighting, and parking; LTE-M for card readers, patient monitoring, security systems, and product tracking. Many modules support both, so you can decide per market.

NB-IoT vs LoRaWAN

The difference is ownership. With NB-IoT, the operator decides where coverage exists and you pay per SIM. With LoRaWAN, you add coverage wherever you place a gateway, and data flows through a LoRaWAN network server you run or rent. The guide to how LoRaWAN works covers classes and gateways, and the overview of LoRaWAN, NB-IoT, Mioty, and others adds the smaller technologies.

What Happened to Sigfox?

Sigfox, the French company that built a global network for tiny messages, went into receivership. On April 21, 2022, the Commercial Court of Toulouse named UnaBiz, a Singapore-based IoT company and Sigfox operator, as the new owner. At the time, the network ran in 75 countries through local Sigfox operators.

In September 2025, UnaBiz's two French companies entered court-supervised reorganization under a continuation plan. UnaBiz said activity would continue normally and no other group entity was affected.

The technology hasn't changed: messages carry up to 12 bytes, with a contractual limit of 140 uplinks and 4 downlinks per day. If you run a Sigfox fleet, check coverage and your contract in each country. For a new design, compare it with NB-IoT and LoRaWAN on coverage at your real sites and on how many module suppliers you can buy from.

Where NB-IoT Is Available: US, Mexico, and Spain

NB-IoT only works where an operator has switched it on. The GSMA's Mobile IoT deployment map lists commercial LTE-M and NB-IoT launches by country (last updated April 2026), and each operator's own page confirms its current offer.

United States

T-Mobile runs the nationwide network it launched in 2018, and Verizon supports NB-IoT and LTE-M on its 4G LTE network. AT&T's LPWA page now lists NB-IoT as available outside the United States and sells LTE-M at home. LTE-M therefore runs on all three national carriers and NB-IoT on two, so a US design is safer starting with LTE-M or a dual-mode module.

Mexico

Telcel offers LTE-M and NB-IoT networks for business customers. On the GSMA map, Telcel is the NB-IoT operator listed for Mexico, while AT&T and Movistar appear with LTE-M.

Spain

All three large networks list it. Telefónica (Movistar) publishes an NB-IoT coverage map through Telefónica Tech, Vodafone sells NB-IoT for remote metering, smart lighting, asset trackingATermAsset trackingIoT asset tracking locates and monitors physical assets (vehicles, containers, equipment) using GPS, BLE, UWB or LoRaWAN.View profile, and connected agricultureAIndustryAgricultureView profile, and Orange builds IoT projects on its LTE-M, NB-IoT, and 5G networks.

2G and 3G Shutdowns

Many older M2M devices still use 2G or 3G, and those networks are going away. Verizon completed the retirement of its 3G CDMA network by December 31, 2022. In Spain, according to Vodafone's summary, Vodafone began switching off 3G in 2022, Movistar planned to finish in 2025, and Orange and MasOrange set December 31, 2027 for 3G, keeping 2G as a residual technology until 2030. In Mexico, ask your operator for its plan before buying 2G or 3G hardware.

Coverage maps show expected outdoor service. Before you commit, measure signal quality at the exact mounting point, inside the cabinet or the pit, with the module you plan to use.

NB-IoT Modules and SIMs: What to Check Before You Buy

Bands and Categories

The module must support the LTE bands your operators use in each country; the BC660K-GL datasheet, for example, lists 17. Prefer Cat NB2 for new designs, and consider a dual-mode LTE-M and NB-IoT module if you sell in more than one market. US carriers also certify devices, and AT&T requires an approved device for its LTE-M plans.

SIM, Plan, and Roaming

Every device needs a SIM, because the spectrum is licensed. It can be a removable card, a chip soldered to the board, or an eSIM whose operator profile can be changed remotely. Before you sign, ask whether the plan covers NB-IoT specifically, whether it allows the PSM and eDRX timers your battery budget assumes, and which partner networks accept NB-IoT roaming.

Firmware and Power

Battery life depends as much on firmware as on the radio. Report on a schedule or when a value changes, batch readings, and keep messages small. A firmware image is large next to a daily reading, so plan field updates carefully. Then pilot at your worst sites and measure energy per message and lost messages before you scale.

When to Choose NB-IoT

Choose NB-IoT when most of these are true:

• The device doesn't move, or only moves between reports.
• It sends small messages a few times a day or less.
• It sits indoors, underground, or inside metal enclosures.
• You don't want to install or maintain gateways.
• An operator offers it where the devices will be.
• The application can wait seconds or minutes for a reply.

Choose LTE-M when devices move, need faster responses or voice, or get frequent firmware updates. Choose LoRaWAN when you want to own the network, have many devices on one site, or need coverage no operator provides.

Take three projects in one region. A gas utility reading meters in basements fits NB-IoT. A logistics company tracking returnable containers between plants needs LTE-M, because the devices move. A farm with hundreds of soil probes and weak cellular coverage is better served by LoRaWAN gatewaysLHardwareLoRaWAN GatewaysLoRaWAN gateways: SX1302/1303 chipsets, indoor vs outdoor units, Network Server (ChirpStack, TTN), packet forwarder and how to build your own.View profile it controls. If you're weighing options for a real deployment, talk to the team and bring your site list and reporting interval.

Connecting NB-IoT Devices to Cloud Studio IoT

Cloud Studio IoT is a white-label IoT platform that device manufacturers, system integrators, and service operators use to deliver IoT services under their own brand. It isn't a mobile operator: the SIM and the network come from your operator, and the platform receives the data once it reaches the internet.

An NB-IoT device connects like any other IP device:

• Over MQTT: each instance has its own MQTT server, with TLS on port 8883 and credentials managed in Gear Manager. The device publishes to {MQTTUserID}/uplink/{DeviceAddress} and, if it takes commands, subscribes to {MQTTUserID}/downlink/{DeviceAddress} while awake. See flexible data exchange over MQTT and what an MQTT broker does.
• Over the HTTP API, the device posts readings with an access token. For models the platform doesn't know, a script decodes the payload.
• If the device speaks CoAP, LwM2M, or non-IP, the operator's platform or your own middleware forwards the data over HTTP or MQTT.

Because these devices report rarely, set each device model's offline timeout a little longer than the reporting interval. The platform raises a device offline alarm when a device stays silent past that time and closes it when data arrives again.

Sites on LoRaWAN come in through your network server, with integrations for The Things Stack, LORIOT, ThingPark X, Helium, ChirpStackCTermChirpStackChirpStack is an open-source LoRaWAN Network Server to deploy and manage private end-to-end LoRaWAN networks.View profile, and Orbiwise. Cloud Studio IoT does not operate a LoRaWAN network server; it integrates with yours and can receive from several at once, so mixed fleets share the same dashboards, alerts, and telemetry history.

The platform already handles cellular devices. In the Canary Islands, for Gesplan (Government of the Canary Islands), 240 solar-powered 4G sensors, not NB-IoT, went into 120 schools across the seven islands in 18 working days instead of the 79 planned, with 120 public-link dashboards. The cloud service runs on AWS, and the Cloud Studio IoT platform can also be installed on-premise.

Key Takeaways

• NB-IoT is a 3GPP LPWAN on licensed spectrum for fixed devices that send small, infrequent messages from hard places.
• PSM, eDRX, and repetitions explain both its battery life and its latency.
• LTE-M covers moving devices and voice; LoRaWAN gives you your own network.
• Check operator support, bands, SIM terms, and real signal at the mounting point before you buy.

Frequently Asked Questions

Is NB-IoT the same as LTE?

No. NB-IoT is built on LTE and runs on operators' LTE networks, but it is a separate radio technology with its own narrow carrier, simplified protocols, and device categories (Cat NB1 and Cat NB2). It's designed for small sensor messages, not phone traffic or video, and operators add it inside an LTE carrier, in its guard band, or in separate spectrum.

Is NB-IoT 4G or 5G?

Both, in a sense. It was standardized in 3GPP Release 13 as part of LTE Advanced Pro, the 4G family, and it runs on LTE networks. 3GPP later included NB-IoT and LTE-M in its IMT-2020 submission to the ITU, so both also count as 5G technologies for massive IoT. You don't need a 5G network to use them.

Which is better, NB-IoT or LTE-M (Cat-M1)?

It depends on the device. NB-IoT fits stationary sensors that send small, infrequent messages from hard-to-reach places, like meters and parking sensors. LTE-M fits devices that move, need faster responses or frequent firmware updates, or carry voice, such as trackers and wearables. In the US, LTE-M is available on more carriers.

What is the difference between NB-IoT and LoRaWAN?

NB-IoT uses licensed spectrum on a mobile operator's network, so you need a SIM and a plan but no gateways. LoRaWAN uses unlicensed sub-GHz spectrum, so you can run your own gateways and network server or use a public network. One depends on the operator's coverage; the other lets you add coverage wherever you place a gateway.

What is the range of NB-IoT?

There's no fixed distance. Range depends on the operator's cell layout, the band, the antenna, and where the device sits. The standard describes coverage as link budget instead: up to 164 dB of maximum coupling loss, 20 dB more than GPRS, enough to reach many basements and underground pits. Test signal quality at the exact mounting point.

Does an NB-IoT device need a SIM card?

Yes. It runs on licensed spectrum, so every device needs a subscription with a mobile operator or an IoT connectivity provider. The SIM can be a removable card, a soldered chip, or an eSIM with a remotely changeable profile. Check that the plan covers NB-IoT specifically, plus power saving features and roaming.

Is Sigfox still working?

Yes, the network still runs, but the company has changed hands. A French court named UnaBiz the new owner of Sigfox in April 2022, and in September 2025 UnaBiz's French companies entered a court-supervised continuation plan while activity continued. Coverage depends on the Sigfox operator in each country, so check your markets before starting a new design.