What is LTE-M and is it right for your IoT project?

What is LTE-M?

LTE-M is a cellular communications technology designed to meet the needs of machine-to-machine (or IoT) communications. It is a low-power wide area network (LPWAN) that was defined by the 3GPP and is widely deployed across the world by LTE network operators.

One of the essential tasks in developing and launching an IoT solution is deciding how it will connect to the network that carries its data.

The most capable and secure method is cellular connectivity. By using standard mobile phone networks, it gives operators of IoT devices a level of flexibility not possible with non-cellular technologies such as Wi-Fi.

Cellular connectivity is divided into two groups – the first is high data rate cellular, based on mobile networks such as 3G, 4G and 5G. This is the choice if your cellular IoT application will be using a lot of data, such as real-time video, or will move around a lot as part of a wearable device or on a vehicle.

The other main choice is the newer LPWAN cellular, which offers lower rate data but also has lower power demands and lower bandwidth requirements.  Two of the main technology options are NB-IoT and LTE Cat-M.

Unpacking LTE-M

LTE stands for Long Term Evolution and is essentially 4G mobile technology. LTE-M, or LTE-Machine Type Communication, is a low power, wide area technology designed to meet the needs of IoT solutions.

For an LTE-based IoT network to be a success, it needs to offer certain characteristics – long battery life, low costs, supports a large number of devices, good penetration to indoor spaces like buildings and long range.

LTE-M, also known as LTE Cat-M1 or just Cat-M1 (sometimes abbreviated to LTE CAT-M or just CAT-M), offers all these advantages. As a low power wide area technology, LTE-M helps devices achieve a battery life of 10 years or more by allowing the device to sleep when not in use. As IoT devices are often left unattended for long periods, this is a big contributor to cutting the costs of deployment.

IoT devices will also be required to operate within buildings or even underground, which can make it difficult to send and receive signals. LTE-M’s deep penetration abilities make it the ideal access solution to connect devices in these challenging places.

Where the technology really wins is in its compatibility with existing LTE networks. Because it uses existing base stations, coverage is not a problem, meaning devices can be highly mobile. This is also good for network providers wanting to offer LTE-M access, as they only need to upload new software rather than build new antennas. It is also compatible with 5G-NR, making IoT devices based on it usable throughout the lifecycle of 5G.

Initially offering a data rate of 1Mbps, making it ideal for devices that transmit small amounts of data over long periods of time, the latest standard upped this to 4Mbps, giving greater mobility and voice capability. This also makes it the solution of choice for data rich use cases such as those that exchange video.

LTE-M use cases

With many applications needing low data rates or real-time communications, LTE-M enables a large number of use cases.

One of the biggest trends of recent years has been smart cities. LTE-M is ideal for connecting and controlling numerous facilities such as public lighting and environmental monitors as well as traffic management signs and car park occupancy sensors.

Its ability to give access where other technologies cannot reach can also give the use of smart meters a big boost, allowing monitoring of water and gas flow in buried pipelines and easier energy measurement in large buildings.

Because it connects readily to existing mobile networks, LTE-M is the ideal solution for mobile applications in areas such as logistics, including fleet control and keeping track of vehicle positions to minimise the loss of goods.

This high mobility of the technology also lends itself to wearables such as fitness trackers and health monitors, as well as uses such as remote care and tracing of elderly and vulnerable people.

Low power wide area networks revolutionized the Internet of Things and LTE-M was a major part of the revolution, alongside NB-IoT. Yet compared to NB-IoT, it offers more flexibility and scope while still providing many of the same benefits.

Overall, LTE-M is a great option for migrating 2G and 3G IoT devices, as well as higher bandwidth applications that also demand low power use. With the advance of 5G, which it also supports, LTE-M will be a major contender for IoT solutions for many years to come.