What is 5G?

Oct 1, 2021Uncategorized0 comments

what is 5g

“Nationwide 5G” is here, but it isn’t making much of a difference for many people. Both AT&T and Verizon are running forms of 5G that light up a ‘5G’ icon on your brand-new smartphone but feel and work precisely like 4G.

That may lead people to wonder what the big deal is with 5G. Is what we see 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 in the US, we’re getting the former without the latter.

Things will start to turn, though. T-Mobile’s “ultra capacity” 5G won our Fastest Mobile Networks 2021 tests by showing speeds much faster than 4G starting in late 2021. In addition, the upcoming C-band networks may change the game for AT&T and Verizon.

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

With the 5G transition, there’s another twist. There are three main kinds of 5G—low-band, mid-band, and high-band—and while the US put its initial bets on low and high, it turns out that mid-band is probably the best way to do it. T-Mobile has mid-band—that’s the “ultra capacity” stuff—but AT&T and Verizon had to wait for the C-band auction, which just ended, to get theirs.

So following that plan, while we’re getting fits and starts of 5G right now, you should expect the big 5G applications to crop up in 2022 or later.

1G, 2G, 3G, 4G, 5G

First of all, if you hear about 5G Wi-Fi or AT&T’s “5G E” phones, they aren’t 5G cellular. So here’s a full explainer on 5G vs. 5G E vs. 5GHz: What’s the Difference?

And if you hear that 5G means millimeter-wave towers on every lamppost, that’s not true. That’s only one of the three primary forms of 5G we see right now.

The G in this 5G means it’s a generation of wireless technology. While their data transmission speeds have technically defined most generations, 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. Then, 2G technologies, such as CDMA, GSM, and TDMA, were the first digital cellular technologies. Next, 3G technologies, such as EVDO, HSPA, and UMTS, brought speeds from 200kbps to a few megabits per second. Finally, 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: more prominent 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 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 with 4G/5G links for quite some time.

That symbiosis between 4G and 5G has caused AT&T to get overenthusiastic about its 4G network. As a result, the carrier has started to call its 4G network “5G Evolution” because it sees improving 4G as a significant step to 5G. It’s right, of course. But the phrasing is designed to confuse less-informed consumers into thinking 5G Evolution is 5G when it isn’t.

While 2G and 3G are going away soon, 4G has many years ahead as part of the 5G equation.

Low, Middle, and High

5G gives carriers more options in terms of airwaves than 4G did. It most notably 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.

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

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

With new phones in low- and mid-band 5G, you can combine two 100MHz channels for 200MHz 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 that carriers can split channels between 4G and 5G based on demand. That’s what Verizon has been using for its “nationwide” 5G. It doesn’t free up any new airwaves for 5G—it just reuses odds and ends of 4G—so we haven’t seen DSS 5G offer much better performance than 4G.

Low-band 5G

Operates in frequencies below 2GHz. These are the oldest cellular and TV frequencies. They go great distances, but there aren’t extensive channels available, and many of those channels are being used for 4G. So low-band 5G is slow. However, it acts and feels like 4G, for now. Low-band, 5G channels, are from 5MHz in width (for AT&T) up to 20MHz (for T-Mobile), so you can see they aren’t roomier than 4G.

Complicating things, AT&T and T-Mobile low-band phones sometimes show 5G icons when they aren’t even using 5G, making it hard to tell any difference.

Mid-band 5G

is in the 2–10GHz range. That covers most current cellular and Wi-Fi frequencies, as well as frequencies slightly above those. These networks have a decent range from their towers, often about half a mile, so these are the workhorse networks carrying most 5G traffic in most other countries. Most other countries have offered around 100MHz to each of their carriers for mid-band 5G. In the US, T-Mobile’s “ultra capacity” 5G network runs on channels of up to 100MHz of mid-band. AT&T and Verizon both just bought some C-Band spectrum between 3.7 and 4GHz, which they’ll start rolling out at the end of 2021.

High-band 5G

or millimeter-wave is the new stuff. So far, this is primarily airwaves in the 20-100GHz range. These airwaves haven’t been used for consumer applications before. They’re concise range; our tests have shown about 800-foot distances from towers. But there are vast amounts of unused spectrum up there, which means very fast speeds using up to 800MHz at a time. We’ve seen speeds over 3Gbps on Verizon’s high-band network, which it calls “ultra-wideband.” Unfortunately, in our Fastest Mobile Networks 2021 tests, we found that Verizon’s network only showed around 3% coverage in the cities we surveyed. AT&T and T-Mobile also have some high-band. However, they generally describe it as only for high-density hotspots, like college campuses and football stadiums.

High bands have been used before for backhaul, connecting base stations to remote internet links. But they haven’t been used for consumer devices before because the handheld processing power and miniaturized antennas weren’t available. Millimeter-wave signals also drop off faster with distance than lower-frequency signals do, and the massive amount of data they transfer will require more connections to landline internet. So cellular providers will have to use many smaller, lower-power base stations (generally outputting 2–10 watts) rather than fewer, more powerful macrocells (which output 20–40 watts) to offer the multi-gigabit speeds that millimeter-wave networks promise. Also, the waves are pretty weak when they get to you because of the swift drop-off.

Across many major cities, the carriers installed these “small cells” to increase 4G capacity starting in 2017. In those cities, they need to bolt an extra radio onto the existing site to make it 5G. There’s a struggle going on elsewhere, though, where carriers are having trouble convincing towns to let them add small cells to suburban neighborhoods. That’s similar to previous struggles over establishing cellular service at all in many of these towns.

Verizon is trying to enhance its high-band 5G coverage by dealing with companies that create 5G extenders and repeaters, such as Pivotal Commware.

How 5G Works

Like other cellular networks, 5G networks use cell sites that divide their territory into sectors and send encoded data through radio waves. In addition, each cell site must be connected to a network backbone through a wired or wireless backhaul connection.

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

5G networks need to be much more intelligent than previous systems, as they’re juggling many more and smaller cells that can change size and shape. But even with existing macro cells, Qualcomm says 5G will be able to boost capacity four times over current systems by leveraging wider bandwidths and advanced antenna technologies.

The goal is to have far higher speeds available and far higher capacity per sector, at far lower latency than 4G. The standards bodies aim at 20Gbps speeds and 1ms latency, at which point exciting things begin to happen.

Where Is 5G Available?

5G is now “nationwide,” although, with the carrier’s very different approaches to it, you’re going to have different experiences in other places.

Verizon has a slower “nationwide” 5G based on shared 4G channels and fast, high-band 5G in more than 60 cities, with online coverage maps here.

T-Mobile currently has a slow nationwide low-band 5G network that covers most of the country.  Faster mid-band protecting 165 million people, with a coverage finder here, and some limited high-band that I haven’t been able to find a recent coverage update for.

AT&T has slow low-band across much of the country and high-band in many “venues” such as stadiums and campuses. It calls the low-band “5G” and the high-band “5G+.” The company has low-band maps and a high-band venue list here.

Which 5G Phones Are Coming Out?

5G phones are mainstream now; expect any phone over $300 to have 5G on board. The next target is C-band, the frequencies which AT&T and Verizon will turn on next year. The Apple iPhone 12 series, the Galaxy S21 series, the Google Pixel 5, and many other AT&T and Verizon 5G phones released in 2021 have C-band.

Low- and mid-band 5G is less expensive to implement than high-band 5G, so many AT&T and T-Mobile phones lack high-band 5G. I’m of two minds about whether or not that matters. More technology is better, and the companies do own a lot of high-band airwaves. But they’ve been highly reticent about what they plan to do with them, so it’s unclear what advantage high-band will bring you in AT&T and T-Mobile phones. On the other hand, if you want to dot all your i’s, the OnePlus 9 Pro, the Galaxy S21 series, the Galaxy Z Flip 3 and Fold 3, the Galaxy Note 20 Ultra, the iPhone 12 series, and the Pixel 5 all have high-band.

Other countries have even more 5G phones, with Huawei, Oppo, Realme, Xiaomi, and others. Unfortunately, they generally don’t work on US 5G networks because they don’t support our frequency bands; they use European and Asian mid-band systems we don’t have here.

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 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. Sprint’s mid-band has been in use at least since 2007; parts were first used in 1963.

The US’s most significant 5G worries tend to be around high-band, or millimeter-wave, 5G. This is the short-range type that requires a lot of small cell sites, so the infrastructure is more visible than before. The ironic thing about worrying that millimeter-wave will fry your cells isn’t that it’s too strong, but that it’s too weak: It’s blocked by leaves, walls, glass, cars, clothing, and skin.

Power levels are critical. Bluetooth and microwave ovens run on the same frequency. Because millimeter-wave signals are technically called microwaves, some people are convinced they are literal microwave ovens that will fry us. But a firefly isn’t a blowtorch, and the 5G systems are more on the firefly end of things.

Studies of mmWave have shown that it doesn’t penetrate human skin well and that its most potent effect, at levels of power higher than any 5G network uses, is that it makes things slightly warmer. However, at the levels 5G networks use, there’s no perceptible effect on people.

But the most self-condemning thing about the mutable 5G conspiracists is that they don’t care about any of these details. Of course, 60 megahertz is much lower than any wireless network frequency; they might mean 60GHz, but no 5G network is using that yet either. As for the oxygen, well, there’s a network of pseudo-scientists with degrees in things like “natural health” who are claiming all sorts of complete nonsense on YouTube.

Here’s our full story on why 5G is safe.

What’s 5G For?

Most of the real-world 5G demos we’ve seen involve people downloading Netflix very quickly on their phones. That kind of usage is table stakes to get the networks built to develop more exciting applications in the future.

On phones, OnePlus CEO Pete Lau said that 5G could make onboard storage irrelevant, which dovetails with ideas I heard around the launch of the Samsung Galaxy S20. The Galaxy S20 takes huge 108-megapixel photos and 8K videos, which quickly eat up your storage and are difficult to upload unless you have a fast 5G connection. On a trip to Korea, I found that high-quality video chat was a significant driver for wanting 5G.

5G home internet shows one significant advantage over 4G: huge capacity. Carriers can’t offer competitively priced 4G home internet because there isn’t enough capacity on 4G cell sites for the 346GB of monthly usage most homes now expect. (The pandemic era has pushed that number higher as people work and learn from home.) So 5G, if implemented right, could increase home internet competition in the US. Unfortunately, according to a 2016 FCC report, 51 percent of Americans only have one option for 25Mbps or higher home internet service. Verizon has launched an unlimited 5G home internet service, but it is tough to sign up for so far.

5G home internet is more manageable for carriers to roll out than house-by-house fiber optic lines. Rather than digging up every street, carriers have to install fiber optics to a cell site every few blocks and give customers wireless modems. We have a review of T-Mobile’s 5G home Internet service, which so far is better than DSL but not as good as fiber.

During the 5G hackathon – the top ideas included a game streaming service, a way to do stroke rehab through VR, intelligent bandages that track your healing, and a method for parents to interact with babies who are stuck in incubators. But, of course, all of these ideas need the high bandwidth, low latency, or low-power-low-cost aspects of 5G.

The Future of 5G

Driverless cars may need 5G to kick into action, our editor Oliver Rist explains. The first generation of driverless cars will be self-contained, but future generations will interact with other cars and smart roads to improve safety and manage traffic. So basically, everything on the road will be talking to everything else.

To do this, you need extremely low latencies. So while the cars are all exchanging tiny packets of information, they need to do so almost instantly. That’s where 5G’s sub-one-millisecond latency comes into play when a package of data shoots directly between two cars or bounces from a car to a small cell on a lamppost to another car. (One light-millisecond is about 186 miles, so most of that 1ms latency is still processing time.)

Another aspect of 5G is that it will connect many more devices. Right now, 4G modules are expensive, power-consuming, and demand complicated service plans, so much of the Internet of Things has stuck with Wi-Fi and other home technologies for consumers, or 2G for businesses. 5G will accept small, inexpensive, low-power devices, so it’ll connect many smaller objects and different kinds of ambient sensors to the internet.

The most significant change 5G may bring is in virtual and augmented reality. As phones transform into devices meant to be used with VR headsets, the very low latency and consistent speeds of 5G will give you an internet-augmented world, if and when you want it. The minor cell aspects of 5G may also help with in-building coverage, as it encourages every home router to become a cell site.

To stay up to date with 5G, sign up for our weekly Race to 5G newsletter. And if you’re looking to the future, read our 6G explainer to stay ahead of the curve.




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