We hope this gives you some guidance on the factors to consider when you’re looking at developing an Cat-M1 enabled IoT product of your own. This article is the first in a planned series of articles aimed at helping you explore technologies that can improve your product designs. Check back regularly for new entries in the series.
Key Considerations for Cat-M1 LTE Product Development
The Internet of Things (IoT) is undergoing a global boom. Worldwide, the market for IoT products was US$212 billion in 2019, more than doubling in size since just 2017. Forecasts suggest that the total global demand will grow to US$1.6 trillion by 2025. IoT is, understandably, a very attractive space for designers and manufacturers to be in these days.
New machine-to-machine (M2M) cellular communication technologies have emerged to help enable these IoT applications. In this article we’ll focus on the implications of LTE-M (machine-type communication), a form of low-power wide-area network (LPWAN) technology that you can incorporate into the design of your IoT products. A related technology—narrowband IoT (NB-IoT)—will be discussed in a future article. LTE-M and NB-IoT technologies offer greater range, lower power consumption, and lower cost as compared to traditional LTE technologies. While LTE-M and NB-IoT technologies enjoy these benefits, they do so at the expense of a lower available bandwidth—which we’ll discuss more in a moment—and that’s important to consider as you decide on the needs for your products.
Within LTE-M technology, Cat-M1 is the prevailing standard today, offering up to 1 Mbps up/down line rates using a single antenna. Given the specifics of LTE-M technologies, what are the key considerations you should have in mind as you develop an IoT Cat-M1 enabled product?
A key advantage that Cat-M1 possesses over NB-IoT is the ability to use TCP connections, allowing for regular socket connections as well as HTTPS and other major protocols.
Bandwidth Required by Application
The first factor to consider is how much bandwidth your specific application requires. As mentioned, Cat-M1 does have lower available bandwidth, so it’s not for every application. Typical actual throughputs are in the 300 kbps range, or lower. If your device requires more bandwidth, then you may fall into a more expensive, traditional LTE category such as Cat-1.
A key advantage that Cat-M1 possesses over NB-IoT is the ability to use TCP connections, allowing for regular socket connections as well as HTTPS and other major protocols. Many products use MQ Telemetry Transport (MQTT) in Cat-M1 applications to help minimize the data consumption.
Power Consumption and Battery Life
Cat-M1 is tremendously power-optimized, which is a plus if yours is a battery-powered application. In some cases, Cat-M1 can offer 10+ year battery runtimes! Cat-M1 modules can enter power-saving mode (PSM) with most cellular carriers to reduce sleep consumption to the microamp (uA) level. Most Cat-M1 modules can also use extended discontinuous reception (eDRX), another feature that helps reduce the average power consumption by increasing the duration between paging cycles.
Remember: battery life is inversely proportional to how often and how much data is transmitted and received.
Battery life is inversely proportional to how often and how much data is transmitted and received.
Module Size
One significant advantage of Cat-M1 modules is that they come in very small sizes. For example, at the time of writing, the smallest Cat-M1 module on the market is the Nordic Semiconductor nRF9160 at 10 x 16 x 1 mm. Even smaller modules will enter the market later in 2020. For applications where size and space are prime considerations, Cat-M1 can provide a great solution.
Regulatory Requirements
Likewise, regulatory and testing requirements (and their associated costs) that your product will face before going to market vary both by country and by carrier. This makes it vital to ensure the Cat-M1 module you select has the required certifications for the countries in which your product will operate.
Ensure existing modular approvals cover the antenna solution you pair with the module; otherwise, significant re-testing will be required (and will be expensive). When operating in the US, select a module that already has FCC, PTCRB (for AT&T) and/or GCF (for Verizon), and carrier certification (e.g. AT&T, Verizon, T-Mobile, Sprint). While you will always need to do testing on your final product, selecting a Cat-M1 module that is pre-certified will keep the final certification costs to a minimum.
To mitigate the impacts these different geographic and carrier requirements can have on your product rollout, consider launching in limited markets to start (e.g. North America first, then Europe, then Japan, etc.) to validate your product idea. And consider using a carrier or a mobile virtual network operator (MVNO) with coverage in all the countries required. This can greatly simplify your product launch, avoiding the need to negotiate pricing and perform product compliance testing with each potential carrier in each region.
Ensure existing modular approvals cover the antenna solution you pair with the module; otherwise, significant re-testing will be required (and will be expensive).
Target Operating Locations
If where people will be buying your product should factor into your decision about using Cat-M1, so should where people plan on using your product. Is your device going to be used in shipping containers? In concrete basements? In industrial yards? All of these factors will affect your IoT module and antenna choice. Be sure to test thoroughly to validate the required performance from the module and antenna combo you choose. Again, depending on the application, Cat-M1 may not suit all needs.
Traditional SIM vs Embedded SIM (eSIM)
Will your device utilize traditional SIM cards or newer eSIMs?
Traditional SIM cards are installed in a holder within the product and must (in most cases) be swapped out to change carriers.
eSIMs, however, are soldered permanently into the product but can be reprogrammed over-the-air to change carriers. eSIM technology saves space compared to traditional SIMs and can offer enhanced reliability. However, they are not supported in all markets or by all carriers, so be sure to check with your carrier for availability and pricing before making your decision on which to use.
Monthly Data Usage
And, finally, consider the monthly data usage of your device. This will impact recurring carrier costs and, ultimately, the choice of carrier. Aim to choose a carrier partner that has flexible data and pricing so that you can scale up or down as necessary.
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