Internet of Things

NB-IoT vs LTE-M: Comparing IoT Communication Protocols

February 24, 2024

NB-IoT vs LTE-M: Comparing IoT Communication Protocols

The internet of things (IoT) is transforming our world by connecting everyday objects and devices to the internet. To enable widespread IoT adoption, these connected devices need reliable and low power wireless connectivity. Two of the leading cellular IoT protocols are Narrowband IoT (NB-IoT) and LTE Machine-Type Communications (LTE-M or LTE-MTC). Both are optimized for IoT applications, but have some key differences.

What is NB-IoT?

NB-IoT is a Low Power Wide Area Network (LPWAN) protocol standardized by 3GPP in Release 13 for cellular IoT connectivity. Here are some key facts about NB-IoT:

Optimized for IoT: NB-IoT is optimized for low data rate IoT applications that need to send small amounts of data over long distances.
Low power: NB-IoT devices can operate for over 10 years on a single battery charge. NB-IoT uses power saving modes to achieve ultra low power consumption.
Extended coverage: NB-IoT can provide coverage underground and inside buildings. It can also cover very wide areas with strong signal penetration.
Low cost: NB-IoT modules are inexpensive, typically under $5. This makes NB-IoT suitable for large scale device deployments.
Simplified architecture: NB-IoT uses a simplified network architecture for efficient signaling and deployment on existing LTE bands.
Small data packets: Each NB-IoT transmission can send just a few bytes of data. This is ideal for simple sensory information.
Latency: End-to-end latency can be 10 seconds or more, which is fine for non-time critical IoT data.

Overall, NB-IoT provides an energy efficient and cost effective way to connect millions of devices transmitting tiny amounts of non-urgent data.

What is LTE-M?

LTE-M or LTE Machine Type Communications is also standardized by 3GPP as part of Release 13. It has the following key characteristics:

Based on LTE standard: LTE-M uses existing LTE infrastructure and spectrum bands. This provides faster time-to-market.
Optimized for IoT: While supporting mobility like traditional LTE, LTE-M includes optimizations to reduce device complexity and power consumption.
Medium data rate: Each LTE-M transmission can send ~1000 bytes of data. This is more than NB-IoT but less than standard LTE.
Lower power: LTE-M has better power savings compared to standard LTE. Battery life is longer than NB-IoT in active/transmit mode but shorter in standby.
Reduced complexity: LTE-M uses half-duplex operation and a single antenna to reduce device cost and complexity.
Enhanced coverage: LTE-M has better indoor coverage and supports mobility compared to NB-IoT. But its range is less than NB-IoT.
Low latency: End-to-end latency can be 10-15ms for time critical applications like voice over LTE-M.

In summary, LTE-M provides a middle ground between NB-IoT and standard LTE in terms of data rate, battery life, complexity, and latency.

NB-IoT vs LTE-M Comparison

Here is a detailed feature comparison between NB-IoT and LTE-M:

As the table shows, NB-IoT has ultra low data rates, extended coverage, and low device costs suited for simple, stationary IoT devices sending tiny amounts of non-urgent data.

LTE-M has moderately higher data rates and lower latency to support more complex IoT devices that may be mobile and need to send occasionally larger data packets with low latency.

When to Use NB-IoT or LTE-M?

So which one should you choose for your IoT application? Here are some guidelines:

Use NB-IoT for applications like smart meters, asset trackers, environmental sensors, that need to send very small, non-time sensitive data over very long range.
Use LTE-M for applications like wearables, connected cars, home/building automation, that need higher data rates or lower latency.
Use LTE-M if your devices need to support mobility like asset trackers in transit.
Use NB-IoT if your devices are stationary and you need to maximize battery life.
Use LTE-M if you have an existing LTE network – it will have faster time-to-market than deploying new NB-IoT infrastructure.
Use NB-IoT if you need the lowest module cost possible.

So in summary:

For simple, low power, stationary IoT devices sending tiny amounts of non-urgent data – NB-IoT is the best choice.
For more complex, mobile, bi-directional IoT devices – LTE-M is likely the better option.
Consider existing network coverage and cost requirements when deciding between them.

By understanding the pros and cons of NB-IoT and LTE-M, you can select the right cellular IoT protocol for your next IoT product.