IoT Blog
IoT Blog

What is Narrowband IoT (NB-IoT)?

by Gus Vos, Chief Engineer, Technology Standards

As we discussed in our blog A Closer Look at the Five Waves of 5G, business and technology leaders around the world are considering how they can use 5G’s faster data speeds, ultra-high reliability, very low latency, and other advancements to digitally transform their organizations. For example, though 5G networks are still being rolled out, many companies are already looking at how they can use 5G to develop new factory automation, self-healing energy grids, autonomous vehicles and other new types of IoT applications. However, those who are focusing only on 5G might be missing out on the fact that two Low Power Wide Area (LPWA) networking technologies also offer them opportunities to develop and launch transformative new IoT applications. 

These two LPWA technologies -- Narrowband IoT (NB-IoT) and LTE Machine Type Communication (LTE-M, also known as eMTC) transmit data at rates slower than Long Term Evolution (LTE), and 5G New Radio (5G NR). But their low cost, high capacity, low power consumption, and wide coverage (the Four Cs of LPWA) make them well suited for a wide range of IoT applications – particularly Industrial IoT (IIoT) applications, including:

Remote monitoring and preventive maintenance applications for biowaste collectors, commercial washing machines, industrial air purifiers, and other industrial equipment.
Infrastructure monitoring applications for liquid fertilizer tanks, HVAC systems, water treatment, smart meters, street lights, civil structures, parking meters, and other infrastructure. 
Asset tracking and monitoring for high-value mobile tools (like mobile air compressors) and sensitive assets (like seeds and vaccines). 

To help those who are unfamiliar with LPWA technologies (or need a reminder), we have developed this Q&A to answer some basic questions about NB-IoT – soon to be followed by an accompanying Q&A to answer similar questions about LTE-M. 

We hope these Q&As will be useful to those of you seeking to better understand how you can use these LPWA technologies to deploy IoT applications that will allow you to lower costs, reduce equipment downtime, improve customer satisfaction, and launch new revenue generating services.

What is the NB-IoT standard?

NB-IoT is a wireless telecommunications technology standard developed by 3GPP, the international standards body responsible for all major mobile telecommunications standards, including 4G standards like LTE and 5G standards like 5G NR. 

NB-IoT uses the same sub-6 GHz wireless spectrum as the 4G LTE technology, but unlike 4G LTE and other previous wireless telecommunications standards, NB-IoT (along with LTE-M) was developed with the IoT in mind. 

Both NB-IoT and LTE-M are designed to support IoT use cases that do not need very high data speeds but do require devices that are:

Can run for a decade or more using only battery power.
Can connect to cellular networks even if there are hundreds of devices like it nearby.
Can be reached in remote rural locations, inside buildings, or underground.

How does NB-IoT address IoT use case requirements?

NB-IoT addresses the needs of many IoT use cases because it:

Costs less: NB-IoT (like LTE-M and the in-development RedCap device standard) uses half-duplex communications, which means either the module is transmitting data or the cellular base station is transmitting data – not both. This use of half-duplex communications -- combined with NB-IoT’s lower data speeds and its use of lower Radio Frequency (RF) bandwidth and a single antenna -- reduce the complexity and thus cost of NB-IoT devices. These simplifications lower the cost of NB-IoT modules by as much as 50 percent compared to regular LTE Cat-1 cellular modules.
Consumes less power: NB-IoT reduces the power consumed by battery-powered edge modules when they transmit data by up to 75 percent compared to regular LTE Cat-1 modules, thanks to features like Power Savings Mode (PSM) and eDRX (Extended Discontinuous Reception), as well as NB-IoT’s ability to optimize the amount of energy used for small data transmissions. This allows IoT application developers to build devices that can operate for a decade or more using battery power.
Provides more capacity: NB-IoT’s use of narrowband transmission, signaling optimization, adaptive modulation, and hybrid automatic repeat request (HARQ) enables as many as one million NB-IoT devices per square kilometer to connect to the network. 
Delivers better coverage: NB-IoT employs large signal repetition. While this lowers NB-IoT’s data rate, and increases its power consumption, large signal repetition improves NB-IoT’s coverage by 5-10X over other cellular technologies. Thanks to this better coverage, NB-IoT devices can connect to cellular networks even if they are located deep inside a building, in a remote rural location, or even underground.  

Are there different versions of NB-IoT?

Yes. Cat-NB1, the first version of the NB-IoT standard, was introduced in 3GPP Release 13. This version of NB-IoT delivers downlink peak data rates as fast as 26 kilobits per second (kbps) and uplink peak data rates up to 62 kbps, with a latency ranging from 1.6 to 10 seconds.

Cat-NB2, the newest version of NB-IoT, was introduced in 3GPP Release 14. Cat-NB2 increases NB-IoT’s peak downlink data transfer speed to 127 kbps, and its uplink peak data rate to 150 kbps. 3GPP Release 14 also introduces advanced positioning technologies for NB-IoT such as OTDOA (Observed Time Difference of Arrival) and E-CID (Enhanced Cell ID), both of which improve location accuracy. 

In addition, 3GPP Release 14 brings the Radio Resource Control (RRC) connection re-establishment feature to NB-IoT devices. This feature allows NB-IoT devices to transfer their cellular connection from one cell to another cell as the device moves between cells, without having to start this transfer process over again if the device experiences a radio link failure (i.e. a drop). RRC makes it possible to use Release 14 NB-IoT devices for pedestrian, bicycling, and similar types of mobile applications.

What is the difference between NB-IoT and LTE-M?

Though similar in many ways, there are some important differences between NB-IoT and LTE-M. 

LTE-M provides faster data rates than NB-IoT, as well as lower latency (the amount of time it takes for a device to connect to a network and send or receive a message). These capabilities allow LTE-M to support voice communications in addition to data communications, as well as IoT applications (like precision tracking or power grid control) that need more real-time communications. In addition, LTE-M provides much better performance for mobile IoT applications than NB-IoT, despite the mobility upgrades found in Cat-NB2. 

LTE-M's faster speeds also make it better for more data-intensive IoT applications. Additionally, LTE-M, as a natural extension of 4G LTE, benefits from out-of-the box roaming, i.e. the ability to use a SIM card from a network operator on another operator’s network abroad.

However, NB-IoT does have some advantages over LTE-M. Though both LTE-M and NB-IoT provide better coverage than other technologies, most network operators have deployed NB-IoT networks with technologies that deliver the best possible coverage improvements, and LTE-M networks with technologies that provide only partial coverage improvements. In the real-world today, this leads to NB-IoT networks providing better coverage than LTE-M in warehouses, office buildings, and underground locations where signal loss and multiple layers of obstruction can lead to connectivity problems.  

These advantages make NB-IoT a great choice for simple, static, very low-data IoT applications.

What are some NB-IoT use cases?

NB-IoT is well suited for IoT use cases where high data rates, low latency, and high mobility are not required, but low cost, strong coverage, very extensive capacity, and low energy consumption are. 

Examples of such simple, static, low-data, low-energy use cases include:

Crop, livestock, and other agricultural monitoring applications
Fuel, water, and other pipeline and tank management applications
Parking, waste management, street lighting, and other smart city applications
Home and building automation applications

Is NB-IoT 5G?

NB-IoT and LTE-M were initially developed for the 4G LTE standard. However, 3GPP, the standards group responsible for 5G as well as the NB-IoT and LTE-M standards, has made NB-IoT and LTE-M part of the 5G standard. In fact, they are the only standards that 3GPP plans to support for LPWA use cases, which require low cost, low power, high capacity, and low energy consumption. In addition, just as NB-IoT and LTE-M can operate in band with LTE technologies, so can they also operate in band with new 5G technologies, like 5G New Radio (NR). 

Additionally, Dynamic Spectrum Sharing (DSS), a new capability delivered by 5G NR, enables operators to use the sub-6 GHz wireless spectrum currently used by 4G LTE, NB-IoT, and LTE-M for 5G NR as well. While many have focused on how DSS will accelerate the roll-out of NR by expanding the amount of spectrum this new technology can use, DSS will also ensure that Mobile Network Operators (MNOs) continue to support NB-IoT and LTE-M technologies for years to come. 

Because 4G LTE, NB-IoT, and LTE-M can share the sub-6 GHz spectrum they currently use with NR, operators do not need to sunset or stop supporting 4G LTE, NB-IoT, and LTE-M technologies in order to use this spectrum both for 4G LTE, NB-IoT, and LTE-M, and also for NR technologies.

Where is NB-IoT coverage available?

According to this list from the GSMA, an industry organization that represents the interests of MNOs, 103 NB-IoT networks have been deployed around the world as of February 2021. 

In addition, this map from GSMA shows that national NB-IoT network coverage is available today in the United States, Canada, Brazil, Argentina, China, Australia, South Africa, and most of Europe.

What should you look for in NB-IoT module solutions?

Though all NB-IoT modules are based on a common technology standard, modules vary significantly between vendors. When evaluating which module to integrate into your IoT application, some good questions to ask include:

Is the module multi-mode? While the deployment of NB-IoT and LTE-M networks continues to accelerate, there are still regions in the world where national NB-IoT networks are operational, but national LTE-M networks are not (for example, China and Russia). There are also countries where national LTE-M coverage is available but not NB-IoT (for example, Mexico), or where a given operator has no plans to deploy NB-IoT (for example Orange in Europe, or NTT DoCoMo in Japan, which shut down its NB-IoT network after a year of commercial service). By using a multi-mode module with support for both NB-IoT and LTE-M, it is easier to deploy an IoT application globally, knowing that your application can connect to either NB-IoT or LTE-M networks. If you are interested in further simplifying global deployment of your IoT application, consider using modules with a smart embedded SIM (eSIM) that can automatically connect to and switch between NB-IoT and LTE-M networks, allowing you to focus on maximizing the value of the data collected by your IoT devices.
How secure is the module? A poorly designed module can be more susceptible to cyberattacks than a well-designed one. Does the module include built-in security features, such as HTTPS, secure socket, secure boot, and free unlimited firmware over-the-air (FOTA) updates? These and other security features from trustworthy companies with deep-levels of IoT experience will help you protect your IoT data from malicious actors. 
Is the module future-proof? Though the NB-IoT module you are evaluating might address all your needs today, updates to your application or new network technologies might result in you wanting to upgrade or update your edge device’s module in the future. Modules that can be updated with new firmware over the air, and those using a common form factor with consistent pin-out and software interfaces, will allow you to more easily adopt new technologies, helping you future-proof your IoT application.
Does the module support edge processing? Modules that make it easy for you to filter, prioritize, or otherwise process some data at the edge can help you update your IoT application’s rules as your business needs change, reduce data transmission costs, and extend the battery life of your devices.

Where can I learn more about NB-IoT?

The websites and reports listed below can provide you with more information on NB-IoT, and how it can be used for a wide variety of different IoT applications:

GSMA: Mobile IoT in the 5G Future – NB-IoT and LTE-M in the Context of 5G (White Paper)
GSA: NB-IoT & LTE-M: Global Ecosystem December 2020 Executive Summary (Report)
TechTarget: What is narrowband IoT (NB-IoT)

You can also read or view some of our white papers, blogs, contributed articles, webinars, and other Sierra Wireless materials to learn more about NB-IoT, how it is different from LTE-M, and how both of these LPWA technologies enable companies to deploy transformative new industrial, smart city, smart home, and agriculture IoT applications.

What is LPWA (Infographic)
LPWA Technologies: Separating Fact from Fiction (White Paper) 
Low Power, High Returns: How Industrial IoT can benefit from LPWA (White Paper)
What is LPWA for the Internet of Things? Part 1: The Four C’s of IoT (Blog)
LTE-M vs. NB-IoT: What are the Differences? (Blog) 
LPWA: The first network technology designed for IoT (Blog)
Designing Low-Power Applications for LTE-M and NB-IoT LPWA Networks (Webinar)

In addition, Start with Sierra by contacting us directly to talk about your IoT application, and how our WP7702, HL7800 and HL7802 modules and other LPWA solutions can help you use this application to unlock value in today’s connected economy.