narrowband IoT (NB-IoT)

How does NB-IoT work?

NB-IoT is a data transmission standard designed to enable devices to operate in mobile carrier networks. NB-IoT technology uses low bandwidth signals to communicate within existing GSM and LTE technologies.

Specially designed devices and sensors are the basic components in NB-IoT systems. These devices collect information from their surroundings and transmit it to NB-IoT base stations or transmission nodes. Individual base stations are connected to an IoT gateway and IoT cloud application servers for centralized monitoring and data analysis.

NB-IoT employs a new physical layer with signals and channels to meet the requirements of extended coverage in rural areas and deep indoors, while enabling very low device complexity. The underlying technology is much less complex than that of GSM/GPRS modules.

Supported by all major mobile equipment, chipset and module manufacturers, NB-IoT can exist along with 2G, 3G and 4G mobile networks.

What are the benefits of NB-IoT?

The benefits of NB-IoT include:

• Ubiquitous coverage and connectivity. NB-IoT can help support massive numbers of devices by establishing NB-IoT networks that can connect to billions of nodes. Designed for extended coverage indoors, the lower complexity of the devices provides long-range connectivity and communication.
• Low power consumption. NB-IoT doesn't need to run a heavy operating system, such as Linux, or do a lot of signal processing, which makes it more power efficient compared to other cellular technologies.
• Low cost of devices. Because it's easier to create devices with lower complexity, the cost of the devices is significantly low, around $5 per module.
• Multiyear battery life. The enhanced power consumption capability enables NB-IoT to support a multiyear battery life for devices.
• Security. NB-IoT is secured much like 4G, including all encryption and SIM-based authentication features.

Examples of NB-IoT applications

NB-IoT can be used for the following applications:

• Smart metering. NB‑IoT works well for monitoring water and gas meters via regular and small data transmissions. Network coverage is a major problem in rolling out smart metering as meters are often installed in difficult locations, such as deep underground, in cellars or in remote rural areas. NB‑IoT coverage and penetration are able to address this issue.
• Smart cities. NB‑IoT can help local governments control street lighting, determine when trash bins must be emptied, identify free parking spaces, monitor environmental conditions and survey road conditions.
• Smart buildings. NB‑IoT connected sensors can send alerts to facilities managers regarding building maintenance issues. There are also indoor temperature monitoring systems that are based on NB-IoT sensors. NB‑IoT can serve to back up a building's broadband connection.
• Tracking. NB‑IoT provides a secure, inexpensive way to track people, animals and assets when continuous tracking isn't necessary. NB-IoT is good for tracking objects that may not be moving all the time.
• Smart farming. NB‑IoT connectivity enables farmers and cities to capture data from environmental sensors containing NB‑IoT modules that can send alerts if anything out of the ordinary happens. These sensors could be used to monitor the temperature and humidity of the soil, as well as to track the attributes of land, pollution, noise and rain.

NB-IoT vs. Cat-M1

The two major technologies that support massive IoT deployments are NB-IoT and Cat-M1. While NB-IoT and Cat-M1 are both 3GPP standardized technologies, they address different types of use cases based on the strengths of their capabilities.

NB-IoT supports ultra-low complexity devices with very narrow bandwidth, 200 kHz. Because of its narrow bandwidth, the data rate peaks at around 250 kilobits per second (kbps).

Cat-M1, on the other hand, operates at 1.4 MHz bandwidth with higher device complexity and at a greater cost than NB-IoT. With the wider bandwidth, Cat-M1 can achieve lower latency, greater data rates (up to 1 megabit per second) and more accurate device positioning capabilities.

NB-IoT and Cat-M1 devices can sleep for extended periods of time with extended discontinuous reception, a method used in mobile communication to conserve the battery of a mobile device. Both NB-IoT and Cat-M1 also support enhanced signal coverage per base station.

NB-IoT vs. LTE-M

LTE-M, or "Long-Term Evolution (LTE) machine-type communications (MTC)," is an LPWAN technology standard introduced by 3GPP in Release 13.

LTE-M is 5G technology that supports simplified device complexity, low device power consumption, massive connection density and low latency. LTE-M also provides extended coverage and enables the reuse of the LTE installed base. 

LTE-M deployment can be done "in-band" within a standard LTE carrier or "stand-alone" in a dedicated spectrum. It uses the free LTE spread spectrum technology. Device manufacturers that want to deploy on current cellular networks can use LTE-M. On the other hand, NB-IoT uses direct-sequence spread spectrum modulation technology for connectivity versus LTE spread technology. NB-IoT can also be implemented in an LTE carrier's guard band. 

As NB-IoT is very flexible, it can operate in 2G, 3G and 4G band and it removes the need for a gateway, which ultimately saves money. 

NB-IoT offers improved indoor coverage, supports massive numbers of low throughput devices, low delay sensitivity, low device power consumption, optimized network architecture and is very cost effective.

LTE-M, however, is more expensive because several large carriers have patents on the underlying technologies and LTE-M users pay royalties to these companies for their intellectual property.

NB-IoT vs. LoRa

LoRa, which is used as a wide area network (WAN) technology, is a noncellular modulation technology for LoRaWAN, the standard protocol for WAN communications.

Short for long range, LoRa is a low-power, long-range wireless communication protocol developed by the LoRa Alliance, a nonprofit organization dedicated to standardizing LPWAN technologies as a secure, energy-efficient IoT standard.

LoRa is a modulation technology for LoRaWAN, an LPWAN specification intended for long-range communications. LoRa and NB-IoT both operate within LPWAN technology.

Although NB-IoT and LoRa are both low-power wide area network technologies created for low-power devices, NB-IoT has a lower latency compared to LoRa because of the higher device output power, which can offer higher data rates.

NB-IoT operates in the licensed spectrum. However, it can be deployed in-band within a normal LTE carrier or stand-alone for deployments in dedicated spectrum. Because the channel width is very small, it allows the NB-IoT signal to bury inside a larger LTE channel, replace a GSM channel or exist in the guard channels of regular LTE signals.

LoRaWAN is a spread spectrum modulation technique designed to facilitate communication between low-power devices and IoT applications. The LoRa wireless system uses unlicensed frequencies available worldwide to communicate with a network.

Barriers to NB-IoT becoming a norm

The barriers to NB-IoT becoming a norm include:

• Limited device mobility. NB-IoT devices only remain connected within a finite environment and only to one network operator. This could mean limitations for such uses as wearables that leave specific perimeters. If a person with a wearable device, for example, enters another country, the device could become inoperable if the operator doesn't have a local presence.
• Limited data transmission. Voice or video transmission is not an option because NB-IoT can only transmit less than a kilobyte of data per day, about equal to a text message. The NB-IoT data upload rate is around 20 Kbps, low compared to competing technologies. Its bandwidth is about 200 KHz.
• Lacks proof of concept. Because commercial rollouts have been relatively limited, it's hard to determine if the technology has been a success.