How do cellular networks serve the Internet of Things?

Cellular networks provide the backbone for many of the things we know and love, allowing us to access the internet, ride in cars, connect with friends, shop, watch videos, and more. In addition to the personal applications we all know, cellular networks also play a vital role in many IoT applications that are constantly evolving.

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In some of the past articles, we have explored other connectivity technologies, including WiFi, Bluetooth, and LPWAN. The reason we have so many connectivity options is because IoT applications can vary greatly, which means the requirements will vary.

While connectivity technology continues to improve, ultimately, there will always be a trade-off between power consumption, range, and bandwidth. In the past, cellular connectivity has focused on range and bandwidth at the expense of power consumption, meaning it can send large amounts of data over long distances but drains the battery quickly. This is great for devices that are connected to a power source or can be charged frequently, like your phone, but it’s not feasible for IoT applications that require remote sensors and devices to last for months or years.

However, that’s not all when it comes to cellular networks. You may have heard of names like 2G, 3G, and 4G, but new cellular technologies like NB-IoT and LTE-M are specifically targeted at IoT applications. 5G will likely prove beneficial and transformative for IoT as well.

How do cellular networks work?

When we make a call, send a text message, or access the Internet through our mobile devices, we are wirelessly sending signals to nearby cell towers. These cell towers both receive our signals and send signals back to us. Cell towers are part of base stations, which have wired connections to other base stations and the Internet, helping to deliver information across greater distances than a single cell tower could.

Like all wireless communication technologies, cellular networks use electromagnetic waves to send information. Just as your radio has different frequency bands that you can tune to (for example, tuning to 101.1 means you are listening to the 101.1 Mhz frequency), wireless communication technologies also have specific frequency bands in which they operate.

If all wireless communications tried to use the same frequencies, there would be too much noise and interference for clear communication. Therefore, the FCC regulates which frequency bands can be used by whom, and cellular carriers each have specific frequency bands in which they are allowed to operate (for example, Verizon in the 746-757 MHz and 776-787 MHz bands).

However, even with their own designated frequency band, carriers still have to consider interference. If two of a carrier's base stations are close to each other and operating on the same frequency, their signals can interfere with each other and cause problems for people trying to use the network in that area.

The solution to this problem is also the answer to the next question.

Why is it called a "cellular" network?

It is called a cellular network because the network operator divides the area into "cells". Each cell has a cell tower that operates on a different frequency than the neighboring cell towers. For example, if you use a hexagonal arrangement, it means you only need 7 different frequencies to ensure that the same frequency is not used in adjacent cells.

The size of each cell depends on the density of use. In a city, the distance between cells may be only half a mile, while in a rural area the distance may be as much as 5 miles.

When a user moves between cells, its frequency automatically changes to switch to the new cell tower. There is also a lot going on behind the scenes to manage the large number of users using the same network at the same time while on the move.

What does G mean?

Even if all of the above is new to you, you've almost certainly heard of terms like 3G or 4G before. These refer to the third and fourth generations, respectively.

Each generation is a set of standards and technologies defined by a standards body called the ITU Radiocommunication Sector (ITU-R). This organization is responsible for managing the international radio frequency spectrum and standards, which helps ensure efficient use of the spectrum. Without such a body and rules to control who can use what spectrum, different companies and organizations may interfere with each other and reduce overall service levels.

However, it should be noted that even under the same standard, there may still be different technologies. For example, UMTS (Universal Mobile Telecommunications System) is a 3G technology mainly used in Europe, Japan and China, while the CDMA2000 system is used in North America and South Korea.

So what is the difference between 1G, 2G, 3G and 4G?

Starting with the 1G system introduced in the early 1980s, a new generation has been introduced approximately every 10 years since then. Each generation brings new frequency bands, higher data rates, and new transmission technologies (not backward compatible).

Because each generation is different, that's why you might not have 4G coverage on your phone but still have 3G (and why you might not have internet access but be able to make calls and send texts).

Several operators have announced that they will shut down their 2G networks to free up radio spectrum for other uses. Any machine using a 2G radio will need to have its radio replaced with a newer generation radio to continue working.

Is cellular connectivity a good choice for IoT?

It all depends on your specific use case. As mentioned in the introduction, cellular has historically been a poor fit for many IoT applications because it consumes a lot of power and can be costly per unit. This limits cellular connectivity to applications that have a direct power source, need to send a lot of data, don’t involve a large number of devices, and are located in densely populated areas.

For use cases that require sensors/devices to be battery powered, don’t need to send a lot of data, have thousands of devices, or might be remote, cellular has not been a good choice. But some things are changing.

Carriers are pushing new cellular technologies like NB-IoT and LTE-M specifically for IoT. While you’ll still need to be in a densely populated area (to be near a cell tower), these technologies will provide low-cost, low-bandwidth, low-power connectivity that will enable a multitude of new IoT use cases that are currently cost-prohibitive.

Keep an eye out for these cellular technologies as multiple carriers are set to launch their services soon.

What is 5G?

The next generation of cellular connectivity promises to be revolutionary, offering speeds of up to 100Gbps (compared to 1Gbps for current 4G). This massive bandwidth will be a key enabler for many future applications, including self-driving cars, augmented reality, and virtual reality.

Perhaps one of the most transformative impacts of 5G is that it can replace physical cables. Cities and businesses can use 5G to meet their needs instead of doing a time- and resource-intensive build-out on wired infrastructure. This also opens up new applications for using the cloud, which previously might have been limited by the amount of data that needed to be sent, instead relying on local processing.

In addition to high bandwidth, 5G also promises ultra-low latency and high reliability, making it an enabler for industrial IoT applications as well. Factories of the future could abandon wired Ethernet in industrial production environments and become dynamic, reconfigurable factories that change with new demands.

The first 5G specifications were agreed in December 2017, and operators launched 5G in 2019. The full potential of 5G will not be released immediately, but it is a very exciting area.