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Narrowband IoT (NB-IoT)

What is Narrowband IoT?

Narrowband IoT (NB‑IoT) is a Low Power Wide Area (LPWA) technology that works virtually anywhere. Many potential “connected things” are located in remote or hard‑to‑reach areas, at long distances from the next cellular base station, or in shielded areas, such as deep within buildings or underground structures.

When there is  coverage under the aforementioned circumstance,  it  is often  poor and requires  the  device  transmitter  to  operate  at  high  power, draining the battery. Additionally, cellular networks are not optimized for applications that only transmit small amounts of infrequent data. Furthermore, the existing cellular standards don’t support the level of power saving capabilities that NB‑IoT does, which makes these standards unsuitable for inexpensive devices that require battery lives of several years.

NB‑IoT has the ability to connect many more devices to the Internet of Things and make many new applications a reality. It is optimized for applications that need to communicate small amounts of data over long periods of time. Since it operates in licensed spectrum, it is secure and reliable, providing guaranteed quality of service.

Using other cellular air interfaces for a typical NB‑IoT application would be too expensive, as NB‑IoT applications don’t need all their capabilities. NB‑IoT applications focus on low speed, robust data transfer, and an appropriate level of reliability. The low device price and long lifecycle cuts operating expenses and reduces the risk of theft. 

NB‑IoT provides:

  • very low power consumption
  • excellent extended range in buildings and underground
  • easy deployment into existing cellular network architecture
  • network security & reliability
  • lower component cost

Evolution from LTE Cat NB1 to LTE Cat NB2

NB‑IoT was first introduced as LTE Cat NB1 in the 3GPP Release 13 standard that also defined LTE‑M (LTE Cat M1) - both are LPWA technologies in the licensed spectrum. With 3GPP Release 14, the LTE Cat NB2 standard has been set. Release 14 brings several improvements to the NB‑IoT standard:

  • Power class: LTE Cat NB2 introduces a lower power class, allowing devices to work at a maximum transmit power of 14 dBm (Power Class 6), which reduces peak current consumption and allows devices to use small batteries.
  • Power consumption: It also introduces a release assistant indication, which drops the RRC (radio resource control) connection after the device indicates that it has no more upload data and is not anticipating further download data. This saves power, as the device spends more time in sleep mode and further enhances NB‑IoT’s already very low power consumption.
  • Higher data rate: LTE Cat NB2 also improves data connectivity to 125 kb/s for downloads and 140 kp/s for uploads, when running two HARQ processes. This is a 4‑6x faster rate than Cat NB1 and suitable for more use cases as well as firmware upgrades over‑the‑air. LTE Cat NB2 can support higher data rates with up to two HARQ (hybrid automatic repeat request) processes and by enhancing the transport block size to 2536 bits, which requires less time and power to transfer larger messages.
  • Mobility: Release 14 NB‑IoT introduces connected‑mode mobility, which means that connections are no longer dropped, if objects move between cells in a cellular network, as was the case in Release 13. Release 14 also provides limited cellular location functionality for NB‑IoT via OTDOA (observed time difference of arrival) and e‑CID, which provides an estimate of a device’s position, based on the serving cell ID, timing advance and neighboring cell IDs.

Key applications

Smart metering

NB‑IoT is well suited for monitoring gas and water meters via regular and small data transmissions. Network coverage is a key issue in smart metering rollouts. Meters have a very strong tendency to turn up in difficult locations, such as in cellars, deep underground, or in remote rural areas. NB‑IoT has excellent coverage and penetration to address this issue.

Smart cities

NB‑IoT can help local government control street lighting, determine when waste bins need emptying, identify free parking spaces, monitor environmental conditions, and survey road conditions.

Smart buildings

NB‑IoT connected sensors can send alerts about building maintenance issues and perform automated tasks, such as light and heat control. NB‑IoT can also act as the backup for the building broadband connection. Some security solutions may even use LPWA networks to connect sensors directly to the monitoring system, as this configuration is more difficult for an intruder to disable while being easier to install and maintain.

Tracking

NB‑IoT provides a secure, low‑cost and low‑cost way to track people, animals and assets, whenever continuous tracking is not required. It is ideal to track objects that may not be moving all the time or where the long range and low power consumption of NB‑IoT are of specific benefit.

Agricultural and environmental

NB‑IoT connectivity offers farmers and municipalities to capture data from an environmental sensor containing an NB‑IoT module that can send an alert, if anything is out of the ordinary. Such sensors could be used to monitor the temperature and humidity of soil, and in general to keep track of attributes of land, pollution, noise, rain, etc.