With Samsung's Galaxy S20 line, 5G just might go mainstream. Samsung told me it expects sales of 5G phones to shoot up from 1 percent to 18 percent of the US market this year, pushed by the fact that there's no non-5G version of its new flagship. If you want the new phone, you're getting 5G.

5G in the US, so far, doesn't have the network coverage or speed to offer a differentiated experience. AT&T's and T-Mobile's "nationwide" low-band 5G performs pretty much like 4G, Sprint's mid-band 5G only works in parts of 10 cities, and fast millimeter-wave (mmWave) has very poor coverage. It's hard to get enough 5G in the US to relax into using it.

That isn't the case in South Korea, though, where I was a few weeks ago. Samsung and wireless carrier SKT lent me a Galaxy Fold to use for a week, and by the end of it I understood how the 5G experience can feel different.

I don't love the Fold's form factor because it's a pain to type on. Using it to navigate Seoul with Kakao Maps, to read the Washington Post app or to video chat with my wife in the US, it was great. But I do a lot of messaging, and a two-handed square tablet just has really bad ergonomics for messaging.

In terms of foldables, I have more hope for vertical flips like the Motorola Razr and Samsung's new Galaxy Z Flip. I didn't give the Razr a good review because its performance is lousy, but it gets the ergonomics right; typing on the Razr feels just as natural as on any other smartphone.

When 5G Matters Now

Let's start with numbers.

Here in the US, we're used to mean 4G speeds around 30-40Mbps with lots of weak-signal areas and signal failures. The wireless coverage in Seoul is much better than in New York. On Korean carriers' mid-band 5G networks, median downloads speeds hover around 270MBps, according to Ookla Speedtest Intelligence, and I got 5G most of the time I was wandering around town.

Korea's 5G made a difference for me in two ways.

The most compelling was video calling. I use Google Hangouts video calling with my wife, and over 5G it was gloriously clear on the huge Galaxy Fold screen—clearer than on my Airbnb's WiFi, and much clearer than I'm used to from 4G on my Galaxy S10e. The 200-300Mbps 5G connection let me sit in a coffee shop and feel like she was right there. That would go for multi-party video calling, too.

I use Google Photos heavily, creating one library from multiple devices. Typically on a new device, when I scroll back through my history on a cellular network, I see a lot of gray squares as the thumbnails haven't loaded. That wasn't the case on 5G—the thumbnails loaded in near-real-time, making cloud data feel a lot more like local data.

That last bit is going to be one of the huge shifts with 5G going forward, I think. As OnePlus CEO Pete Lau and others have told me, reliable 5G networks blur the line between local and cloud, making more categories of data streamable—all your personal media, for sure, but also games and apps.

These two use cases connect with the features Samsung has put in the S20, but there's an aspect of the S20 that worries me a little. Samsung put a big video-calling button in the S20's dialer—spot on, from my Korean experience—but it's also going to be suggesting 5G as a way to upload huge 108MP photos and 8K videos. Typically, network providers spend a lot more time focused on download speeds rather than upload speeds. Will they be ready for big uploads?

I asked Karri Kuoppamaki, T-Mobile's VP of radio technology development and strategy, and he said it's manageable. "We have quite a lot of headroom in the uplink side. We're keeping an eye on that, and the same levers we have on the downlink capacity, we can provide that on the uplink." In other words, if they have to make room for your video calls, they'll make room.

How Apple Will Sell 5G

With those experiences, I see Apple selling its 5G iPhone based on a pitch around multi-party, high-res video calling. Group FaceTime came with iOS 12, and FaceTime is probably the most popular video-calling service in the US; for many Americans, it's synonymous with video calling in a way that Skype used to be.

Apple doesn't want to oversell 5G capabilities, so it's going to be very cautious about how it markets 5G. But it will have to market 5G; it'll be selling expensive new 5G phones, and it will want people buying those and not older 4G models.

Those high-res, super-sharp, big-screen video calls I experienced in Korea were pretty amazing. Hangouts calling is often pretty choppy and blocky, but sitting in a Korean coffee shop and talking to my wife like she was in the chair next to me definitely changed the game. Expect a lot of ads later this year bringing families together on video, thanks to 5G.

Further Reading

• Report: Apple Designing In-House 5G iPhone Antenna Module
• Report: LG and Samsung Are Developing Portable Displays for Phones
• Motorola Razr vs. Samsung Galaxy Z Flip: Which Is the Finest Foldable Phone?
• Want to Buy a Galaxy Z Flip on Feb. 14? Try a Sprint Store
• More in Race to 5G
• More in Mobile Phones

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