What Is 5G? An Explainer...

All of the network carriers have now launched some form of 5G cellular network. But what exactly is 5G, and how fast is it compared with 4G? Here's what you need to know.

After three years of promises, 2022 will be a big year for 5G.

The new mobile network tech was supposed to ignite a fourth industrial revolution. The "5G" that most of us have experienced up until now has felt just like 4G, with a new icon. All of the hullaballoo over 5G, with no real new experiences, has led people to wonder what the big deal is. Is what we are seeing right now even 5G at all? The answer is yes—technically. It turns out that 5G technology and a "5G experience" are very different things, and right now we are getting the former without the latter.

5G is an investment for the next decade, and in previous mobile transitions, we've seen most of the big changes happening years after the first announcement. Take 4G, for instance. The first 4G phones appeared in 2010, but the 4G applications that changed our world didn't appear until later. Snapchat came in 2012, and Uber became widespread in 2013. Video calls over LTE networks also became big around 2013.

Because the 5G transition is so complicated, and because we have been having a pandemic for two years, this time the shift may take even longer. Scientists in Finland who helped developed 5G technology say that it may be 2027 before we see the robotics, smart objects, and augmented reality we're been promised.

For now, the first big 5G application is a 30-year-old idea: home internet service. Safaricom for instance are using their 5G networks to better compete with cable home internet, adding some competition into a very uncompetitive realm.

The G in this 5G means it's a generation of wireless technology. While most generations have technically been defined by their data transmission speeds, each has also been marked by a break in encoding methods, or "air interfaces," that makes it incompatible with the previous generation.

1G was analog cellular. 2G technologies, such as CDMA, GSM, and TDMA, were the first generation of digital cellular technologies. 3G technologies, such as EVDO, HSPA, and UMTS, brought speeds from 200kbps to a few megabits per second. 4G technologies, such as WiMAX and LTE, were the next incompatible leap forward, and they are now scaling up to hundreds of megabits and even gigabit-level speeds.

5G brings three new aspects to the table: bigger channels (to speed up data), lower latency (to be more responsive), and the ability to connect a lot more devices at once (for sensors and smart devices).

It isn't a clean break with 4G. 5G phones all need 4G networks and coverage. At first, all 5G networks used 4G to establish their initial connections; something called "non-standalone." We're starting to move away from that now into "standalone" networks, but they lose significant performance without an assist from 4G. Part of the 5G spec allows 5G phones to combine 5G and 4G channels invisibly and seamlessly to the user. So most connections will be combined 4G/5G links for quite some time.

How 5G Works

Like other cellular networks, 5G networks use a system of cell sites that divide their territory into sectors and send encoded data through radio waves. Each cell site must be connected to a network backbone, whether through a wired or wireless backhaul connection. 5G changes the way data is encoded, and offers many more options to carriers in terms of airwaves to use.

5G networks use a type of encoding called OFDM, which is similar to the encoding that 4G LTE uses. The air interface is designed for much lower latency and greater flexibility than LTE, though.

The new system opens up "high-band," short-range airwaves that didn't work with 4G technology. But 5G can run on any frequency, leading to three very different kinds of 5G experiences—low, middle, and high.

5G isn't much faster than 4G on the same old radio channels. Instead, the 5G spec lets phones use much wider channels across a broader range of frequencies. The carriers and the FCC have to make those wider channels available, though, and that's where they have largely fallen short.

With 4G, you can combine up to seven, 20MHz channels to use a total of 140MHz of spectrum. Most of the time, though, phones are using 60MHz or less.

With new phones in low- and mid-band 5G, you can combine three 100MHz channels for 300MHz usage—and stack several more 20MHz 4G channels on top of that. In high-band 5G, you can use up to eight 100MHz channels. But if you don't have the airwaves available, you don't get the speeds.

Carriers can also flexibly share channels between 4G and 5G using dynamic spectrum sharing (DSS). DSS makes the walls between 4G and 5G channels movable, so carriers can split channels between 4G and 5G based on demand.

Low-band 5G operates in frequencies below 2GHz. These are the oldest cellular and TV frequencies. They go great distances, but there aren't very wide channels available, and many of those channels are being used for 4G. So low-band 5G is slow. It acts and feels like 4G, for now.

Mid-band 5G is in the 2 to 10GHz range. That covers most current cellular and Wi-Fi frequencies, as well as frequencies slightly above those. These networks have decent range from their towers, often about half a mile, so in most other countries, these are the workhorse networks carrying most 5G traffic. Most other countries have offered around 100MHz to each of their carriers for mid-band 5G.

Where Is 5G Available?

5G is now most urban areas of Kenya, although with the carrier's very different approaches to it, you are going to have different experiences in different places.

Which 5G Phones Are Coming Out?

5G phones are mainstream now; expect any phone over Ksh 30,000 to support it. More mid-band phones will come out this year, and more existing models may be certified over the next few months.

Low- and mid-band 5G is less expensive to implement than high-band 5G, so many phones lack high-band 5G. More technology is better, and the companies do own a lot of high-band airwaves. But they have been extremely reticent about what they plan to do with them.

Is 5G Safe?

Yes. Online conspiracy theories have blamed 5G for everything from cancer to coronavirus, but they tend to fall apart at the slightest tap of actual facts. Low-band and mid-band 5G are based on radio frequencies that have been used for decades. Low-band 5G uses UHF TV bands, which have been in use since 1952. Mid-band has been in use at least since 2007; parts of it were first used in 1963.

What is 5G For?

The first major 5G application is home internet. Home subscribers typically use hundreds ofgigabytes per month, more than our 4G networks are designed to handle. The 5G networks have enough capacity to handle that demand.

5G home internet is easier for carriers to roll out than house-by-house fiber optic lines. Rather than digging up every street, carriers just have to install fiber optics to a cell site every few blocks and then give customers wireless modems.

But home Internet isn't new. The truly new applications are waiting for widespread 5G coverage that is noticeably faster than 4G.

Remotely piloting robots and drones is another 5G use we are starting to see. Because 5G has lower latency than 4G, remote pilots can control vehicles from a distance without lag, and because 5G has more bandwidth, they can get reliable multi-camera video feeds from vehicles to see where they are going.