For years, the idea of 6G was considered science fiction. Now, we’re closer than ever, but there’s still room for improvement, says Josep He Jornet, an associate professor of electrical and computer engineering at Northeastern University.
Jornet worked with NASA, the US Air Force, and Amazon to demonstrate for the first time that high-speed, high-bandwidth wireless communication at terahertz frequencies is possible over long distances. This study, recently published in Nature Electronics, shows that there is a path to large-scale wireless communications that can reduce the digital divide felt by rural communities outside of high-speed fiber optic networks.
“We need to find a technology that can provide an optical connection without the optical issues, and we think terahertz technology is that,” Jornet says.
The terahertz band is the set of frequencies above 100 gigahertz, surpassing the 71 gigahertz limit of 5G. The deployment of 6G wireless has opened this level of service to the general public, but while it has been proven to transmit signals over the terahertz band, it has been nearly impossible to do so over long distances. The distance the information travels is shorter. For terahertz communication, this equates to one-leg communication, he says, Jornet.
However, Journette has a habit of making the impossible possible.
“My research is driven by showing people that what they believe doesn’t work can work,” he says.
Jornet and his team were able to form a 2-kilometer link, the longest terahertz connection ever established on Earth. That said, it wasn’t without its challenges. First of all, the terahertz frequency radio was nothing like Jornet could find on his Amazon. That’s why he turned to his NASA in the first place.
For years, NASA has tinkered with terahertz radio systems to sense signals in space, but NASA’s efforts have focused solely on signal reception. Be careful when sending signals.
Traditionally, a communications radio has a signal generator, a mixer that adds information to the signal, and an antenna that converts the signal into something that can be transmitted over the air. The problem is that the terahertz frequencies are so high that they require so much power to reach that they destroy mixers placed in radios. So Jornet came up with an elegant solution.
“No other mixer can handle that much power. Good, no mixers,” he says.
Instead of placing a mixer after the signal source, Jornet and his team fed information directly into the signal source itself. But doing so would distort the information insanely. Another problem required another creative solution.
“Instead of trying to correct the information at the receiver, we pre-distort the signal,” he says. “Makes the signal ugly as it becomes beautiful when it passes through the source.”
Surprisingly, it worked for Jornet and his team as well. They were at a U.S. Air Force base in Rome, New York. He spent four days establishing a long-range terahertz connection, and by the second day was able to transmit and recover information without error.
“In theory, running the equations seems to work, but the theory requires a lot of assumptions about how the device works internally,” Jornet said. increase. “A lot of times when you go through this, you expect things to go wrong, so I was very surprised that it actually worked.”
The system Jornet and his collaborators designed achieved frequencies and bandwidths that outperformed 5G networks by “more than two orders of magnitude.”
“At 6G, I think we’ll be happy with just one digit more,” he says.
The impact of this kind of high-speed, high-bandwidth connection is immense, offering higher data rates and more connectivity even in rural communities. Fiber optic cables, which form the backbone of modern telecommunications networks, are expensive to implement over long distances, and until recently, 5G deployments left rural communities trapped in the digital divide. But when it comes to wireless terahertz technology, rural communities may have an advantage.
“One of the requirements for this signal to travel is that it must be free of obstacles,” says Journette. “You need to have a line of sight. So if you want to connect towers across farms and land, this is great, otherwise you would have to drill holes and insert fiber optics.”
Jornet predicts that terahertz will start to make a big difference in communications infrastructure even before 6G is available on mobile phones.
Original: New terahertz wireless link could bridge the digital divide, says Northeast researchers
Than: Northeastern University | | NASA
