LTE for IoT: Does 4G Fit Your Use Case?

Eseye

IoT Hardware and Connectivity Specialists

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LTE (Long Term Evolution) is the fourth generation standard of wireless and mobile connectivity technology. Its journey started in 2008 when LTE 4G became the first wireless technology to offer a truly ‘broadband’ experience.

In the years since, different branches of LTE have emerged to cater to specific consumer and business deployments including high-bandwidth IoT and M2M use cases.

This article will give an overview of LTE options available today and the different flavors as they pertain to IoT and M2M initiatives.

What is LTE?

As with other modern cellular technologies, LTE is defined and maintained by the 3rd Generation Partnership Project (3GPP) standards group and the LTE standard was originally introduced under 3GPP Release 8.

In terms of the evolution of wireless connectivity, LTE 4G is indeed ‘long term’. In the 1980s, 1G gave us mobile voice, then 2G introduced roaming and SMS, 3G introduced mobile internet, and 4G emerged in the 2000s as it became clear that data was the killer application for cellular.

Although we’re already onto 5G and 6G in terms of technology evolution, it’s 4G that holds the most promise in terms of finally unlocking the potential of IoT, through wireless coverage, reliability, and bandwidth, and establishing a foundation that will support IoT and M2M initiatives long into the future.

Fifth generation cellular is complementary to 4G, rather than a replacement, and real-world adoption of 5G will be seen first in consumer devices. So IoT deployments being planned today will rely on 4G for the next decade or so, which is why there have been so many technical developments within the LTE standard, mainly focused on improving battery life and energy consumption, while maintaining coverage.

Different versions of LTE and suitability for IoT

4G LTE has evolved along different branches, or categories, as a response to different use cases, and some of these variants have collected multiple technical and colloquial names, resulting in considerable confusion. For example, 3GPP Release 13 in 2016 (known as LTE Advanced Pro), introduced LTE-M (Long Term Evolution for Machines) as an M2M specific variant, but the same technology is also known as:

• LTE-MTC (Long Term Evolution for Machine-Type Communication)
• 3GPP Cat-M1
• LTE Cat M1
• eMTC (enhanced Machine-Type Communication)

Interestingly, the original 3GPP Release 8 from 2008 actually included LTE Category 1 (Cat-1) as something of a precursor to IoT – intended for low power, low throughput devices, but it was largely ignored until the advent of ‘IoT’ some years later. An updated version, LTE Cat-1 bis, was included in Release 13, to better service the vision of IoT we know today.

NB-IoT (Narrowband IoT) is also a competing category designed for machine-to-machine usage that has emerged from the same LTE standard and gained significant recognition and growing adoption.

Overall there are around 20 different categories or flavors of LTE with niche M2M use cases, but it’s really LTE-M, NB-IoT, and Cat-1 (bis) that consistently appear as the top options.

What is LPWAN?

Furthermore, most – but not all – of the categories of LTE fall under the family umbrella of LPWAN (Low-Power Wide Area Network, sometimes just known as LPWA), which are defined as wireless wide area networks providing low bit rate bandwidth between IoT devices, such as sensors operated on a battery. Other technologies such as Sigfox, LoRa, and Weightless also appear in this family.

What is LTE-M?

LTE-M, also known as Cat-M1, is designed for low-power applications requiring medium throughput. It has a narrower bandwidth than LTE, but it does give a longer range, and with this configuration it can lead to power saving and cost savings for large-scale deployments compared to LTE, making it ideal for sensors and wearable devices.

In terms of deployment, LTE-M is just a configuration that needs to be enabled, so if LTE is present then LTE-M is available too. LTE-M supports a backchannel and SMS for device setup and updating eUICC SIM cards, where you can load and switch profiles.

This makes LTE-M devices very attractive in terms of longevity, because they can be built once, shipped, and updated via software and SIM.

What is LTE Cat-1 and LTE Cat-1 bis?

Although LTE Cat-1 is an older technology, dating back to 3GPP Release 8, it offers good support and adoption for IoT devices with low and medium bandwidth needs, stacking up as a solid competitor to LTE-M and NB-IoT due to lower latency and higher bandwidth. That said, it is more power hungry with a shorter signal range.

Cat-1 offers a good migration path for 2G and 3G applications, and is ideal for asset tracking, smart meters, and remote sensors.

LTE Cat-1 bis (‘bis’ is a Latin term for ‘again’) is a revised version of the Cat-1 LTE category more suitable for IoT due to it only requiring one antenna versus the two antenna requirement of Cat-1.This makes IoT devices smaller and more cost effective, but everything else is much the same.

Cat-1 and Cat-1 bis do not fall into the LPWAN family, in fact they are seen as competitors, and while the hardware costs may be higher than LPWAN devices, these categories do provide:

• A higher data rate
• Better coverage
• Lower latency

In a nutshell, LTE Cat-1 bis provides a less complex design based on single antenna while delivering LTE performance, with reduced power consumption and a smaller footprint compared to LTE, making it suited for applications requiring moderate data rates, such as wearables and vehicle telematics, with the exception of very modern high-bandwidth connected vehicle requirements.

What is NB-IoT?

NB-IoT (also known as Cat-NB1) is a narrowband technology standard that does not use a traditional LTE physical layer but is designed to operate in or around LTE bands and coexist with other LTE devices.

NB-IoT is part of the LPWAN family and benefits from a longer range, including better penetration through obstacles such as walls, at the compromise of lower throughput.

Lower bandwidth also exempts NB-IoT devices from device updates however, which complicates longevity, and lacks SMS support, which prevents SIM updates and profile switches. It does consume less power however, and for this reason, it enables a longer battery life when compared to other existing cellular standards.

NB-IoT is suitable for very low data rate applications, providing deep penetration and high-density connectivity, perfect for utility meters and smart city applications.

LTE-M, LTE Cat-1, NB-IoT compared

While the above table shows you a side-by-side comparison of popular IoT connectivity technologies, the main features you should consider for your IoT or M2M deployment, are:

Size of device

The footprint of the device, including battery and antenna support (relevant for LTE Cat-1) could impact size limitations and connectivity solutions.

Coverage

Assess the coverage provided by different connectivity options and whether in-building penetration could be a deciding factor.

Power and battery life

Different connectivity solutions have different power draws, combined with battery size and intended lifespan of the application, this could limit your choices.

Bandwidth and throughput capability

This will impact the amount and frequency of data you can transmit and could impact future device updates. Latency could also be an issue in some applications.

Mobility

Does the device need to move or will it be fixed? Will the device move overseas?

Price

Consider not only upfront costs of the device but also the infrastructure with the ongoing expenses for connectivity.

Benefits of LTE for IoT deployments

Regardless of the category of connectivity you choose, LTE 4G does offer significant benefits for IoT deployments broadly speaking.

Broad coverage: LTE networks offer extensive coverage, ensuring IoT devices can operate in remote or rural areas.

High data rates: LTE supports high data rates, facilitating applications that require real-time data transmission, such as video surveillance.

Low latency: Critical for time-sensitive applications, including autonomous vehicles and industrial automation, where immediate response is crucial.

Security: LTE networks provide strong security features, such as encryption and network authentication, essential for protecting sensitive IoT data.

Scalability: LTE can support a vast number of connections per cell, making it suitable for large-scale IoT deployments.

Potential downsides of using LTE for IoT

The pros of LTE for IoT must be weighed against the cons:

Cost: The cost of LTE modules and operation can be higher compared to other technologies like Wi-Fi or Bluetooth, impacting the overall budget for IoT projects.

Power consumption: While LTE-M and NB-IoT are designed for low power consumption, traditional LTE categories may still consume more power, affecting the battery life of devices.

Complexity: Deploying and managing LTE-based IoT networks can be complex, requiring expertise in cellular technologies.

The future of LTE and 5G

While 5G is another cellular evolution, it is not a replacement for LTE and the two technologies will exist in harmony for the foreseeable future. That said, 5G will be used to expand and enhance LTE 4G deployments, offering even higher speeds, lower latency, and more efficient power usage for IoT applications.

LTE technologies, especially LTE-M and NB-IoT, are also evolving as part of the 5G ecosystem, ensuring future-proofing of IoT solutions.

So is LTE 4G right for my IoT initiative?

When it comes to IoT and M2M deployments and your decision on which RAT (Radio Access Technology) to use, the best approach is to look at the problem you are trying to solve and the use case.

What happens if the data from the IoT device does not arrive in one hour, or 10 hours, 24 hours,72 hours? Would this timeframe have any significant impact on your business?

Consider a smart meter, as long as the usage is reported by the time the billing cycle comes round, the above question doesn’t really matter.

But the response could be different with a tracker. A vehicle tracker could phone home once a day, or a few times a day, or only when the vehicle is moving. It depends on the use case. 

In a healthcare application checking a patient’s blood pressure once a day is a very different use case to a cardiac monitor which might have to trigger an alert at any time.

For a point of sale, a vending machine, or an electric vehicle charger, latency is a factor as the device needs to interact with the customer in near real time.

To respond to these hypothetical applications:

• For a smart meter: NB-IoT would work, as the data payload is low and infrequent and latency is not important.
• For a tracker: In some cases NB-IoT would work, but realistically, LTE-M or Cat-1 bis would suffice as latency is important.
• For healthcare: LTE-M would work in some cases but Cat-1 bis might be better when latency is important.
• For a POS, vending machine, or EV charging station: Cat-1 bis is the best solution as latency is critical here.

LTE 4G covers a wide variety of use cases for IoT and M2M but the devil is in the detail and when choosing a particular category of connectivity it’s always best to start by looking at the application for guidance.

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Eseye

IoT Hardware and Connectivity Specialists

LinkedIn

Eseye brings decades of end-to-end expertise to integrate and optimise IoT connectivity delivering near 100% uptime. From idea to implementation and beyond, we deliver lasting value from IoT. Nobody does IoT better.

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