Questions Remain About Push to 6G, With 5G in Early Stages: IEEE Experts

As the focus on 6G intensifies, Henning Schulzrinne, former FCC chief technology officer, warned an IEEE summit Tuesday that 5G hasn’t turned out as expected, at least not yet. We’re at “an inflection point” in the discussion of next-generation networks, said Schulzrinne, now a Columbia University professor.

We now have a sense of how 5G is turning out, Schulzrinne said. “We’ve also seen that some of the predictions we’ve had about 5G turned out to be somewhat off the mark,” he said. Most applications aren’t limited by speed, the number of very-low apps “has turned out to be pretty limited” and we can already support a large number of devices “that probably are sufficient for most applications,” he said.

The average U.S. household now uses 500 GB of data per month, at a cost of about 12 cents/GB, Schulzrinne said. The most important question is whether networks can support mobile and residential data demands cost effectively, he said. The key metrics are the cost of broadband per GB used and the cost per square kilometer of coverage to “just provide basic, non-volume-constrained coverage for low-bandwidth IoT applications,” he said.

Schulzrinne noted the cost per GB using cellular is about 20 times higher than over a home Wi-Fi network. Unless carrier next-generation networks support “a dramatic reduction in bandwidth costs, that is competitive with home broadband,” high-bandwidth apps are likely to use Wi-Fi, not 5G or 6G, he said. “There is just an order of magnitude-plus difference in costs,” he said: “Getting bandwidth at home is just so much less expensive.” One goal of carriers should be making sure some level of connectivity is available “pretty much everywhere” even in the most remote areas, he said.

“We shouldn’t get hung up too much about what type of killer application is going to be driving 6G, we just have to accept” the transition “is going to happen,” said Mischa Dohler, Ericsson chief architect. “I know what 6G will be able to do,” he said: “I don’t know why, and I don’t know how to do it yet.” Questions about whether the next G is needed come up during every wireless generation and people asked the same questions during the 3G and 4G eras, he said.

The first focus on how 6G will be used will be consumers, Dohler said. “It’s also machines, injecting intelligence into the machines,” he said: “It’s about reprogramming the world, so we believe there’s going to be a future for digital twinning.” Everyone is talking about connectivity, reaching everywhere in the world, he said. “There are huge challenges there, from network design, from spectrum and the physical layer,” he said. Security and privacy have to be built in, he said.

“It seems that we are insatiable in our will to consume more and more gigabytes for either the same or less dollars,” said Reinaldo Valenzuela, Nokia Bell Labs director-wireless communications research. “I’m sure we’re going from 5G to 6G thanks to the unstoppable development of technology,” he said. Valenzuela sees augmented and virtual reality and other immersive experiences as a top driver for 6G. In parallel “a very strong trend that we see happening, even surprising most of us, is autonomous transportation” including cars and buses, he said. “Enveloping all of this is the amazing changes with artificial intelligence,” he said.

“We have a long road to go before we can really trust this new world,” Valenzuela said. He noted attendees at the hybrid IEEE conference couldn’t hear one of the morning speakers because of connection issues. “We have a lot of work to do,” he said. Valenzuela questioned whether satellite broadband will address connectivity issues. “Are we really going to have a business case for all these low-orbit satellites?” he asked. The most promise is offered by the use of reusable launchers and satellites that can communicate with a standard handset, he said.

We can’t do wireless within new spectrum bands, Valenzuela said. “As you go up in frequency, the propagation losses get higher and higher,” he said. Low-band base stations can reach consumers 20 miles away, but in dense areas small cells reach 100 meters, he said. “Still, new spectrum is unavoidable,” he said.

Some 200 providers have deployed 5G worldwide, but we're still in “the very early stages,” said Chih-Lin I, China Mobile chief scientist-wireless technologies. Most of what has been deployed is based on 3rd Generation Partnership Project Release 15, rather than the two follow-up releases, she said. 5G improvements are ongoing, now, “particularly in terms of efficiency” and the use of the cloud and making networks more intelligent, she said.

“We are really in the middle of a fundamental, very profound transformation,” Chih-Lin said. The current phase will take at least 10 years and many challenges remain, she said.