What Is LTE-M?

LTE-M (or “Long Term Evolution for Machines”) is a type of low-power, wide-area network radio communication technology and a 4G cellular network designed specifically for the Internet of Things (IoT).

There are two main versions of LTE-M: Cat-M1 and Cat-M2. Cat-M1 offers higher data rates and supports voice communication, making it suitable for more data-intensive IoT applications. Cat-M2 focuses on ultra-low power consumption and extended coverage, ideal for devices requiring long battery life and operation in challenging environments.

Low-Power Wide-Area Networks (LPWANs) provide cost-effective and efficient connectivity for Internet of Things (IoT) applications. Leveraging Power Saving Mode (PSM) and extended Discontinuous Reception (eDRX), LTE-M-connected devices can achieve battery lifespans of up to 10 years or more.

Designed for Machine-to-Machine (M2M) communication, LTE-M is a specialised branch of LTE technology. It allows IoT devices to transmit and receive data efficiently without significant battery drain, unlike traditional 2G, 3G, and 4G networks.

Key Takeaway: LTE-M, or Long-Term Evolution for Machines, is a lower-bandwidth, 4G cellular network technology developed by the 3GPP and designed to support the Internet of Things (IoT). It features two main versions: Cat-M1 and Cat-M2.

Key Advantages of LTE-M, Cat-M1 / Cat-M2

LTE-M offers many benefits for IoT applications, making LTE-M an attractive choice for a diverse set of IoT use cases. These advantages include:

• Extended Coverage
• Power Consumption & Efficiency
• Mobility Support
• Quality of Service & Data Speed
• Device Costs
• Future Proofing
• Firmware Over The Air (FOTA)

1. Extended Coverage

LTE-M offers coverage in areas where other cellular network technologies may struggle to reach or penetrate. This is due to its Maximum Coupling Loss (MCL) of 156 decibels (dB), versus an MCL of 142 dB for LTE. The signal can overcome obstructions from challenging infrastructures and geographies such as basements, subways, car parks, countryside areas or dense urban locations.

In contrast to other LPWANs, LTE-M networks can use 4G LTE infrastructure for improved link budget and enhanced signal penetration capabilities.

LTE-M is often the ideal technology for IoT applications. 4G connections now account for over 50 percent of world wide mobile connections, and its status is expected to reach 95% global coverage by 2026. This ensures IoT applications such as remote soil moisture monitoring for hard-to-reach agricultural land or asset tracking for fleet management in built-up city locations are much less susceptible to challenges faced by other LPWANs.

2. Power Consumption & Efficiency

One cornerstone feature of LTE-M is its low power consumption.

Why is this important?

Regular cellular networks talk to mobile devices constantly in order to maintain Tracking Area Updates (TAUs) to local towers and base stations, causing the mobile device to consume power continiuously.

In contrast, most IoT applications will either send and receive smaller volumes of data periodically, or rely on a trigger of some sort, such as a sensor being activated or when a certain criteria is satisfied. Therefore, the power consumption of these devices is often significantly lower than regular cellphone devices.

When paired with IoT devices, LTE-M technologies like Power Saving Mode (PSM) let devices “sleep” when they’re not in use, and Extended Discontinuous Reception (eDRX) lets devices check downlink information over an increased time period. What are the benefits of these features? Significantly extended battery life, ultimately allowing devices to perform for several years from a single charge.

This is particularly valuable for applications like smart meters, environmental sensors and asset trackers which rely on devices located in hard-to-access places or are just impractical to charge on a frequent basis.

Essentially, LTE-M’s reduced power consumption makes it ideal for battery operated IoT devices which require less power, enabling up to a 10-year battery life on a 5WH (watt-hour) battery.

3. Mobility Support

LTE-M is optimised for IoT applications that are moving due to its low latency of approximately 10-15 milliseconds. Applications such as fleet management, asset tracking, or wearable devices all benefit from seamless connectivity on the move. This mobile capability ensures reliable data transmission even when devices are in transit.

4. Data Speed

When you look back at the uplink and downlink rates of historic LPWAN networks like 2G and 3G (UMTS), LTE-M performs significantly faster at 1 Megabit per second (Mb/s). While LTE-M offers moderate data transmission rates compared to LTE, these are perfectly sufficient for the majority of IoT applications along with any Over-The-Air (OTA) update requirements and applications with small data requirements.

LTE-M data transfer capabilities ensure efficient communication between the IoT device and the network without the need for high-speed data, balancing the trade-off between performance and power consumption.

5. Device Costs

4G networks were built primarily for use with smartphones, while LTE-M networks were specifically created for IoT devices.

This key difference in the intended use case means components required for LTE-M-connected devices are simpler and more affordable than those needed for traditional 4G devices – even though both use 4G LTE infrastructure. This cost-benefit has resulted in the widespread deployment of LTE-M-connected IoT solutions across various industries.

6. Future Proofing

Unlike LPWANs and other legacy networks not equipped to handle large download requirements, LTE-M can handle significant downloads. This makes it ideal for major IoT device updates to software, features, or security. LTE-M’s future-proofing OTA capability is essential for IoT devices that need to remain operational over long periods and may require updating.

LTE vs. LTE-M

When 4G technology emerged in the late 2000s, various technological standards competed for dominance in various nations. LTE emerged as the triumphant standard, finding global adoption. Essentially, the terms “4G” and “LTE” are synonymous, with LTE being the prevailing technology used worldwide.

When comparing the two, Long-Term Evolution is designed for high-speed, data intensive mobile internet, while LTE-M is tailored for IoT devices needing low power and extended coverage.

Key Comparisons

• Data Rates: LTE (up to 300 Mbps) vs. LTE-M (up to 1 Mbps)
• Power Consumption: LTE-M is optimised for low power usage
• Coverage: LTE-M provides better coverage in difficult environments
• Use Cases: LTE for high-speed applications; LTE-M for IoT
• Cost: LTE-M is more cost-effective for IoT

If you’re looking for more information, the IEEE Xplore Digital Library offers scholarly articles and research papers on LTE and LTE-M, providing technical depth and background information.

LTE-M vs. NB-IoT

When comparing LTE-M and Narrowband IoT (NB-IoT), it’s important to consider the specific needs of your IOT application:

• Coverage: LTE-M offers better mobility support as it harnesses a 4G infrastructure, making it suitable for applications that require more penetrative and far-reaching coverage. Meanwhile, NB-IoT is optimised for stationary devices with deep coverage requirements. NB-IoT can handle slightly higher levels of interference as it has a higher Maximum Coupling Loss (MCL) although few carriers have established roaming agreements for NB-IoT networks compared to LTE-M.
• Data Speed: LTE-M provides data speeds that are 10x faster compared with NB-IoT, and latency iscan be up to 100 times lower. This makes it suitable for applications needing moderate data transmission.
• Power Consumption: Both technologies are designed for low power consumption. NB-IoT may have a slight edge in extremely power-sensitive applications due to its even lower data rates and extended battery life capabilities. It’s important to note that employing NB-IoT’s slower data speeds means devices will need to stay online for longer, consuming more power.
• Use Cases: LTE-M is extremely versatile, and suitable for both stationary and mobile applications, whereas NB-IoT excels in fixed-location sensors and devices.
• Future Proofing: LTE-M comes out on top as a superior option to NB-IoT for future device update requirements due to its low latency and high data speed capabilities

Technology	Maximum Uplink Speed	Maximum Downlink Speed	Latency	Maximum Coupling Loss (dBs)	Bandwidth
LTE-M	1 Mbit	1 Mbit	10-15 ms	156	1.4 MHz to 5 MHz
NB-IoT	127 Kbit	159 Kbit	1.6-10 s	164	180 KHz

Learn about: NB-IoT Vs LoRaWAN

Getting Started With LTE-M

Are you looking for a provider that offers premium LTE-M service? Here at Soracom, we offer secure, reliable, and affordable LTE-M connectivity for IoT devices and applications deployed across the UK, Europe, and beyond.

Connect with our team of IoT experts to discuss your project in detail and discover how you can deploy on the UK’s most powerful IoT connectivity platform for M2M devices.

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