IoT operators today have many options for connecting their IoT devices with cellular technology. Your next IoT deployment might thrive on low-data, low-power standards such as NB-IoT or LTE-M. Or, maybe you’re looking forward to New Radio standards RedCap and eRedCap, which may offer stronger performance on 5G networks. For many IoT deployments, however, optimal connectivity comes from existing and well-established 4G networks. In fact, IoT’s legacy 4G standards, Cat 1 and Cat 1bis, remain ideal for a variety of IoT use cases. Here’s why, followed by some examples of the most common Cat 1 IoT use cases of today.
Introducing the Cat 1 and Cat 1bis Standards
It’s important to see that one cellular technology isn’t necessarily better than another, but rather—from Cat 1 to RedCap—the range of connectivity options simply offers different capabilities. Choosing a module to connect your IoT device can be like buying a vehicle: Do you need a work truck, a passenger van, or a compact commuter? The answer depends on what you want the vehicle to do for you. Similarly, your choice of cellular IoT technology depends on the requirements of your particular use case.
You’ll want to consider the following features or capabilities when connecting your IoT device:
- Bandwidth
- Range
- Power consumption
- Network availability
- Cost
The goal is to choose the technology that offers the best match for your needs across all these domains. That might be NB-IoT or LTE-M—but, more often than you might think, it’s Cat 1 or Cat 1bis.
What is Cat 1, and How Does it Differ from Cat 1bis?
Long-term evolution (LTE) Cat 1 is a cellular standard first defined in 2008 under the mobile networking authority 3GPP’s official Release 8. This standard supports a download rate of 10 megabits per second (Mbps) and an upload rate of 5 Mbps, which is an ideal transfer rate for many IoT applications, including video and voice applications, that need throughput higher than the 1 Mbps rate of LTE-M.
The modules that support Cat 1 connectivity have two antennae. Modules that use the updated Cat 1bis standard—first defined in 3GPP’s 2016 Release 13—need only a single antenna. Elimination of one of the antennae simplifies form factor, reduces the number of required components, and therefore lowers cost.
More importantly, however, the Cat 1bis standard is an optimized version of the LTE Cat 1 standard. For example, it adds a more effective Power Saving Mode along with other efficiencies—but works on the same network infrastructure as any Cat 1 device, so it can operate anywhere, on any LTE network worldwide.
| What does the bis in “Cat 1bis” mean? Most cellular engineers can explain what Cat 1bis is, but few know where it got its name. Bis is not an acronym, nor is it an obscure technology description. Luckily, there’s a simple explanation. Bis is a Latin word that means “twice” or “second.” The implication is that Cat 1bis is the second version of the Cat 1 standard. When 3GPP’s engineers developed the Cat 1bis standard, they needed a designation that reflected both the updates and an essential similarity to the original Cat 1 standard. They settled on adding this Latin modifier, resulting in the term Cat 1bis. |
5 IoT Use Cases for Cat 1 and Cat 1bis Connectivity
The key benefits of Cat 1 and Cat 1bis are global availability, connection speed, and similarity to 3G connections (thereby simplifying migrations as 2G and 3G networks sunset). Each of the following use case examples demonstrates one or more of these advantages.
1. Global Asset Tracking Systems
Mobile network operators must invest in technology upgrades to support connections via LTE-M or NB-IoT. In some parts of the world, MNOs chose to invest in LTE-M; in others, they invested in NB-IoT, with some regions supporting both. This has resulted in uneven availability.
Global asset tracking systems require global coverage to enable consistent and continual tracking all over the world. Since every cellular network already supports Cat 1, Cat 1 or Cat 1bis is often the best choice for uninterrupted connectivity.
2. Consumer IoT Products for a Global Market
Say you sell e-scooters in various cities around the world. Some areas support LTE-M, while others don’t. (For now, we’ll set aside NB-IoT, which typically lacks the bandwidth you need for IoT applications—including over-the-air upgrades.)
In this scenario, the typical approach is to create two stock-keeping units (SKUs) for the same product. One SKU represents e-scooters with LTE-M modules. Another SKU represents the same model e-scooter with a Cat 1 module. The better solution is to create a single Cat 1bis SKU, even if Cat 1bis modules end up costing a little more on a per-part basis than LTE-M modules, because you’ll save cost in the long run.
This single-SKU approach is beneficial because SKU proliferation adds considerable complexity and cost to your operation. As mentioned, unlike LTE-M, Cat 1 coverage is available on any cellular network. Using a Cat 1 module to connect all your e-scooters, you can issue a single SKU and greatly simplify your stockkeeping and logistical operations.
3. IoT Video
Both Cat 1 and Cat 1bis have enough speed and bandwidth to transfer video files whereas LTE-M may not. That makes them ideal choices for a range of consumer IoT products, from dash cameras to security systems where video is required.
4. IoT Voice
Similarly, Cat 1 and Cat 1bis support voice applications. In the world of IoT, that unlocks a range of devices, from medical alert and PERS devices to smart home security products, or any other application that has a voice control element.
5. Low-Power and Long-Range Devices
As we mentioned Cat 1bis offers an effective Power Saving Mode, or PSM. This allows IoT devices to run on batteries for extremely long periods—sometimes up to a decade or more. Some devices, such as smart meters or environmental or agricultural monitoring devices, must stay connected over long distances.
While Cat 1 may not be the best choice for every IoT device, these examples illustrate some of the technology’s strongest selling points. Cat 1bis is an excellent alternative for cellular connectivity when LTE-M is not available or when the application’s required data rate is above what LTE-M can deliver. Perhaps the greatest advantage of Cat 1, however, is just how long it has been around. As a technology that’s been in use since 2008 or so, Cat 1 is proven to be highly reliable.
That’s also true for the hardware that uses Cat 1 and Cat 1bis. Manufacturers of IoT chips and modules have perfected the features of these standards and optimized them for IoT. To sum up, Cat 1 and Cat 1bis standards remain valuable and cost-effective connectivity technologies for IoT deployments like the ones listed above—and many more.
