It’s been a big week for 5G, the next generation of wireless networks. Samsung announced its first 5G capable phone, the S10, on Wednesday. Qualcomm announced a new 5G modem on Tuesday. But President Trump is aiming higher.
“I want 5G, and even 6G, technology in the United States as soon as possible,” Trump wrote in a tweet urging carriers to pick up their pace. “It is far more powerful, faster, and smarter than the current standard.”
Trump won’t see anything called 6G during his presidency, even if he wins re-election next year. The 3GPP, the organization responsible for standardizing wireless network technologies, started work on the 5G standard in 2011 and hasn’t completely finalized it yet. No group has even begun work on a 6G standard. It will likely be a decade or more before anything labeled 6G arrives.
According to a report commissioned by the wireless industry group CTIA, the US lags China and South Korea in readiness for 5G. There are a number of reasons for that, including the need for the Federal Communications Commission to free up more wireless spectrum for 5G use, as well as a need for more fiber-optic connections to handle the “backhaul” between cellular towers. But so far no country has a nationwide 5G network.
Still, some researchers are already hard at work on one technology that could underpin 6G: terahertz wireless. “I’m glad he [Trump] is talking about it,” says Theodore Rappaport, director of New York University’s NYU Wireless program. “It’s time to start talking about what 6G will be.”
5G isn’t just one technology or standard, but rather a constellation of different technologies. The 5G technology that has captured the most attention is called millimeter wave. Millimeter wave refers to the portion of the wireless spectrum above around 24 GHz where there’s plenty of unused bandwidth that could help carriers deliver wireless speeds as fast, or eventually much faster, than home broadband services provide today.
The WIRED Guide to 5G
Terahertz wireless, which is a bit of a misnomer, technically refers to anything between 30 GHz and 3 THz. But the term is typically used to refer to anything above 100 GHz, explains Sundeep Rangan, associate director of the NYU Wireless program. Rangan and his colleagues want to make it possible to tap into the enormous amount of bandwidth that would be available at these very high frequencies, which are not widely used today.
On Thursday, the FCC announced a proposal to open a huge amount of spectrum above 95 GHz for experimental use. The upshot, Rappaport says, is that terahertz frequencies could be just as fast as wired connections, meaning that wireless connections could be used for backhaul instead of fiber-optic connections.
Rangan can’t say for sure that the 3GPP will include terahertz wireless as part of an eventual 6G specification, but says it’s a major focus for industry research. “All the machinations are moving towards this eventually being part of 6G,” he says.
In addition to 6G wireless networks, terahertz frequencies might be useful in radar systems for autonomous vehicles. Radars measure the distance of objects by sending out radio waves and measuring how long they take to bounce back. Today’s radars aren’t great at determining the exact position of an object, Rangan explains, so self-driving car systems now tend to use lidar, which uses lasers instead of radio waves to provide more precision. But radars using terahertz radio waves might work as well as lidar systems, and better in foggy conditions, while costing less.
But Rangan says commercial applications of terahertz frequencies are still a good 10 years away. Millimeter wave signals have very short wavelengths, and so have trouble passing through barriers like people, walls, or trees. Terahertz waves are even shorter, and so those problems are even worse. Terahertz wireless hardware will also likely be quite power hungry.
Rangan and his team are working to design circuitry for use with terahertz frequencies, with a focus on energy efficiency. Other researchers at NYU Wireless are focused on improving the reliability of terahertz transmissions. Meanwhile, companies like Samsung have joined NYU Wireless’s industrial affiliate program.
Rappaport says the shift from 5G to 6G could happen more quickly than the shift to 5G, because carriers will have installed much of the necessary infrastructure, such as a shift from large cell towers to “microcells.” But it will still take years to develop all the technologies necessary to make 6G a reality. Even the combined efforts of academia and industry won’t allow Trump to tweet on a 6G phone anytime soon.
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