Let’s talk LTE-M and NB-IoT
According to Ericsson’s 2019 Mobility Report, the number of cellular IoT connections will rapidly expand from 1 billion in 2018 to 4.1 billion in 2024. As NB-IoT and CAT-M1 are projected to make up 45% of those connections, labelling them ‘future proof’ is a pretty safe bet.
We thought that it was about time to unpick which of these cellular networks could work for your IoT project. After all, you might be part of that 45%.
What is CAT-M1?
You may have come across the term CAT-M1, which is often grouped with Long Term Evolution for Machines or LTE-M. GSMA states that it is a term that refers to the LTE-MTC, the low power wide area technology standard published by 3GPP in the Release 13 specification.
LTE-M specifically refers to LTE CAT-M1. According to Jersey Telecommunications, CAT-M1 works by using the existing LTE infrastructure to send out lower frequency waves. It operates on a 1.4 MHz bandwidth, which means that it can achieve data rates of up to 1 Mbps. By operating in such a wide bandwidth, CAT-M1 has a lower latency and relatively accurate device positioning capacity in comparison to NB-IoT. The latency is far lower than NB-IoT, as it hits around 100-150 milliseconds in normal coverage and a few seconds in Extended Coverage Mode A.
LTE-M will coexist with other cellular offerings, such as 2G, 3G (whilst they’re still kicking) and 4G. This means that devices get all of the benefits of the security and privacy features of a mobile network but for an IoT project. Pretty cool.
What is NB-IoT?
NB-IoT stands for Narrow Band Internet of Things. It is a low power wide area network specifically aimed at enabling a range of low complexity and low delay sensitivity IoT devices.
It works by using low-frequency channels that previously went unused because they were only able to transfer small amounts of data. NB-IoT picked up the slack in these channels and voila – perfect for IoT applications. Specifically, IoT projects that only need to send small amounts of data with long intervals in between. It works on a very narrow bandwidth, 200 kHz, which means that the data rate is much lower than CAT-M1 and peaks at around 260 kbs per second.
To give you a quick heads up about this particular cellular network, latency is around 1s and increases to several seconds in extended coverage.
Check out this very helpful infographic from Jersey Telecommunications for a breakdown of the differences between LTE, LTE-M and NB-IoT:
So, what are CAT-M1 and NB-IoT good for?
There are multiple use cases for both. However, there a few things to consider before connecting to these cellular networks.
Think about what type of data you want to send. NB-IoT sends much smaller data packets than CAT-M1, meaning that it is the cheaper offering of the two. However, CAT-M1 is able to send higher volumes of data – even from moving IoT devices. This means that it is perfect for long distance coverage across industries that need to track things such as shipping, monitoring drivers and reporting across moving operations. It can also send small packets of audio data as it is supported with VoLTE. (If you’re struggling to remember what this network is good for, remember the ‘M’ in CAT-M1 can stand for mobility.)
The use cases for NB-IoT are typically stationary devices where short delays are fine. It can even work with geographically dispersed devices, so works perfectly with projects such as animal tracking, warehouse monitoring, asset tracking and smart metering.
For those of you interested in the nitty gritty side details, check out this table for uplink and downlink speeds:
| Bandwidth | Downlink (kbps) | Uplink (kbps) | |
| LTE-M (CAT-M1) | 1.4 Mhz | 300 | 375 |
| NB-IoT | 200 kHz | 26 | 63 |
[Source: Ericsson’s ‘Key technology choices for optimal massive IoT devices’ (2019)]
What can Pycom offer you?
You might be familiar with Pycom’s cellular offering or you might be new to it (if so, hi!)
We have two development boards that support cellular LTE-M and NB-IoT. Our triple bearer board, the GPy supports WiFi, Bluetooth and cellular. Our other cellular development board is the five-network FiPy, that supports WiFi, Bluetooth, Sigfox, LoRa and cellular – it all depends on which one you want to work with.
They’re both fantastic for large or small scale rollouts, or even if you just want to set something up at home to have a play around with!
Interested in setting up your IoT device with a cellular LPWAN? Have a look at this map from GSMA to see where the nearest NB-IoT and LTE-M network is deployed and who exactly is deploying them.