The future depends on connectivity. From artificial intelligence and self-driving cars to telemedicine and mixed reality to as yet undreamt technologies, all the things we hope will make our lives easier, safer, and healthier will require high-speed, always-on internet connections.

To keep up with the explosion of new connected gadgets and vehicles, not to mention the deluge of streaming video, the mobile industry has introduced something called 5G—so named because it’s the fifth generation of wireless networking technology.

The promise is that 5G will bring speeds of around 10 gigabits per second to your phone. That’s more than 600 times faster than the typical 4G speeds on today’s mobile phones, and 10 times faster than Google Fiber’s standard home broadband service—fast enough to download a 4K high-definition movie in 25 seconds, or to stream several at the same time.

Eventually anyway. While US carriers have introduced 5G networks in dozens of cities, the first ones aren’t nearly that fast.

At first many carriers began rolling out 5G by building atop their 4G or LTE networks, which produced lots of connectivity, but not at the speeds most associated with 5G. Gradually, the major American telecom carriers have introduced standalone versions of their networks, meaning they don’t piggyback on existing infrastructure. T-M0bile’s offering covers 1.3 million square miles, or 34 percent of the US. When T-Mobile acquired Sprint earlier this year, it picked up a substantial amount of wireless spectrum, which is now part of T-Mobile’s network. Dish Network acquired some of Sprint’s wireless assets as a condition of the merger, and the satellite company is now developing its own cellular service.

Early in its 5G efforts, AT&T marketed a network it described as 5G E, but experts called it a spiffed-up version of the company’s current LTE network, and the National Advertising Review Board eventually recommended the company stop using that terminology, saying it was misleading consumers. The company says its 5G network reaches 205 million people and offers speeds that are similar to or faster than its LTE offering. In July 2020, AT&T announced that its 5G+ service, which runs in the faster millimeter wave spectrum (more on that shortly), is available in parts of 35 cities.

Like AT&T, Verizon is using mmWave, the fastest part of 5G spectrum, for its network, which means customers can expect fast speeds but, so far, less broad coverage. The company says its 5G Ultrawide offering is available in 36 cities.

Why are the availability and speeds so variable? It’s because 5G service is offered in three different parts of the electromagnetic spectrum. Low-band, which operates below 1 Ghz , can reach speeds of 250 mbps. The trade-off for low-band’s comparatively slower speeds is a broad reach, which means carriers can leave more distance between towers using this kind of equipment.

Analysts call the mid-band of the 5G spectrum the sweet spot, as it has a broad geographic reach and is faster than low-band. Mid-band operates between 1 and 6 GHz and can achieve speeds up to 1 Gbps. AT&T and T-Mobile’s wide-reaching 5G networks operate in the mid-band.

To reach the top speeds associated with 5G, carriers need millimeter-wave (or mmWave) technology, which takes advantage of the very high end of the wireless spectrum. mmWave could enable those 10-Gbps speeds, but it comes with a trade-off: Millimeter-wave signals are less reliable over long distances and are easily disrupted by obstacles like trees, people, and even rain. To make it practical for mobile use, carriers need to deploy huge numbers of small access points in cities, instead of relying on a few big cell towers as they do today.

Of course, for mobile users to take advantage of these new 5G networks, they’ll need new devices. Most major phone makers either offer 5G handsets now or expect to by the end of 2020. Samsung, LG, and Motorola sell 5G-compatible phones; Google is working on a 5G version of the Pixel, and a 5G-compatible iPhone is expected before the end of this year. To date about 4.6 million 5G-compatible phones have been sold, according to the consultancy M Science; that means fewer than 2 percent of Americans with cell phones can take advantage of 5G.

The Race for 5G Dominance

The US has been keen to claim a leadership role in worldwide 5G deployment, but so far it hasn’t fully succeeded. China-based Huawei is the world’s leading maker of 5G network equipment, and while its equipment is deployed widely, the company has faced scrutiny from western nations for its alleged ties to the Chinese government. The Trump administration is intent on keeping Huawei technology out of American networks, and earlier this year the US Department of Justice accused the company of conspiring to steal American trade secrets. Another fear has been that if China is first to 5G, its burgeoning tech industry will create the next global mobile platform; 5G could also give China an edge in the AI race. More devices connected to networks would mean more data. More data with which to train algorithms could mean better AI applications. The US government has also said Huawei can’t use American-built technology in its networking chips. The UK, Australia, India, Japan, and Taiwan are among the countries that have banned Huawei equipment from their networks. The bans stand to benefit companies like Nokia, Ericsson, and Samsung—notably, none of them headquartered in the US—which also make 5G equipment.

As the US struggles to lead on the network side, it’s also behind in 5G from a speed perspective. A recent report from the UK-based research firm Opensignal analyzed the speeds that users typically get and found that Saudi Arabia had the fastest 5G download, topping out at 144.5 Mbps, with Canada ranking second at 90.4 Mbps. (The consultancy didn’t include China in its analysis.) South Korea has the highest rate of 5G adoption, with 10 percent of users on 5G, and its networks ranked third; the US, with an average speed of 33.4 Mbps, ranked 11th. Users are connected to 5G 20 percent of the time or more in only four countries, Opensignal found; the US, where users connected to 5G 19.3 percent of the time, ranked fifth. “The US is much higher ranked on 5G availability than on average download speed because the low-band spectrum is ideally suited to enable great 5G reach and allow users to spend more time connected than in countries with higher frequency 5G spectrum,” Opensignal wrote. In recent tests both Opensignal and PC Magazine found in tests that Verizon offered the fastest 5G speeds among American cell phone carriers. The top download speeds the surveys found varied considerably (an average of 494.7 Mbps from Opensignal and 105.1 Mbps from PC Magazine), but the results suggest that exponentially faster cellular networks aren’t just on the horizon; they’re here.