AT&T Shape Event Highlights 5G Promise and Perils

on June 25, 2019
Reading Time: 4 minutes

OK, let’s get this part out of the way first. In the right conditions, 5G is fast—really fast. Like 1.8 Gbps download speed fast. To put that into perspective, we’re talking 5-10x faster than even the fastest home WiFi, and more than 50x faster than a lot of the typical 25-35 Mbps download speeds most people experience with their day-to-day 4G LTE connections.

The catch is, however, that the “right conditions” are rarely going to be available. At AT&T’s recent Shape Expo event on the Warner Bros. studio lot in Burbank CA, I did actually see just over 1.8 Gbps on a speed test using Samsung’s brand new S10 5G phone when I stood 75 feet away from a tiny cell tower installed as part of a new 5G network on the lot and pointed the phone directly at it. Impressive, to be sure.

However, when I turned away and walked another 50 feet from the tower and held the phone in my hand as you normally would (and not in direct sight of the special 5G antenna that was part of the network), the speed dropped to just under 150 Mbps because the connection switched over to LTE. Now, that’s still nothing to shake a stick at, but it’s more than 10x slower than the fastest connection. This succinctly highlights some of the challenges that 5G early adopters will likely face.

To understand the dilemma, you need to know a bit more about how 5G networks work. First, the good news is that 5G builds on top of existing 4G LTE networks, and whenever 5G signals aren’t there, smartphones and other devices with cellular modem connections (such as wireless broadband access points—often nicknamed “pucks” because they look a bit like hockey pucks) fall back to 4G. Plus, as my experiment showed, it’s often a very good 4G connection, because any phone with 5G also typically has the most modern 4G modems. Similarly, locations that have 5G networks usually have the most current 4G technology installed as part of the network as well. Together, that combination typically means that you’ll get the best 4G network connection you can—to put it numerically, it can be as much as 5x faster than the typical LTE speeds many people experience today.

Within the 5G world, there are two basic types of connections that leverage two different types of radio frequencies to deliver the signals from cellular networks to devices: millimeter wave and what’s termed “sub-6”—short for sub, or below, 6 GHz. Millimeter wave signals (so named because their wavelengths are about 1 millimeter in length) are extremely fast, but they don’t travel far and demand a direct line-of-sight connection. Like Verizon and T-Mobile, AT&T’s initial implementation of 5G networks use millimeter wave technology and the new Samsung S10 5G supports that as well.

So, back to my original test, I was only able to see the crazy-fast 1.8 Gbps download speeds when the phone was within the short range and direct line-of-sight of the 5G tower, which was transmitting millimeter waves at 39 GHz (which happens to be one of the frequency bands that AT&T controls). As soon as I moved a bit away and that connection was lost, both the phone and network connection fell back to 4G LTE—albeit the latest LTE Advanced Pro version of 4G (which AT&T confusingly calls 5Ge, or 5G Evolution). In other words, to really enjoy the full benefits of 5G speed and millimeter wave technology, carriers like AT&T are going to have to install a lot (!) of 5G millimeter wave-capable technology. Thankfully, 5G-specific antennas can be added to existing 4G towers and 5G smalls cells take up much less space than typical cellular network infrastructure components, but there’s still going to have to be a lot more independent 5G cell sites to fully leverage 5G.

Later down the road for AT&T, Verizon and T-Mobile (but in the forthcoming initial implementation of 5G from Sprint), you’ll be able to access the “other” kind of 5G frequencies, collectively referred to as “sub-6”. The sub-6 frequencies can all travel farther than millimeter wave and don’t require line-of-sight, so they can work in a lot more places (including inside buildings). However, they’re also much slower than millimeter wave. As a result, the “sub-6” 5G options will enable much wider coverage but won’t really be significantly faster than many 4G LTE networks. (FYI, all existing 4G radio connections occur below 6 GHz as well, in fact, below 3 Ghz, but they use different methods for connections and different types of radio frequency modulations than 5G.) Practically speaking, this means it will be easier to build out better coverage networks with “sub-6” 5G, but at the expense of speed. It’s a classic engineering tradeoff.

Of course, there’s more to 5G than just speed and some of that potential for future 5G applications was also on display at the AT&T Shape Event. Most notably, reductions in latency, or lag time, can start to enable much better, and more compelling implementations of cloud-based gaming over mobile network connections. Nvidia, for example, showed off a lag-free 5G connected version of its GeForce Now cloud gaming service, which allows you to have a high-end desktop gaming experience powered by Nvidia graphics chips even on older PCs or laptops. In addition, several vendors started talking about delivering higher-quality video and graphics to AR and VR headsets courtesy of future 5G products.

There’s no question that 5G can and will make a large impact on many markets over time. But as these real-world experiences demonstrate, it’s a complicated story that’s going to take several years to really show off its full potential.