Planning for 6G Must Start Now, as 5G Deploys, Experts Say

These are “the really early days when it comes to 6G,” said Chris Woolford, Ofcom director-international spectrum policy. “We’re not in a position yet to talk about exactly which bands or exactly how we’ll make spectrum available,” he said. What we can do is “talk about how regulators are needing to evolve their approach to spectrum management in order to meet these needs of the future,” he said.

“We need to be aware of how innovation is evolving,” Woolford said. “A key role for regulators is to enable and promote innovation and that rate of innovation is accelerating.” Ofcom wants to go beyond the traditional approach on sharing to create spectrum “sandboxes,” he said. Ofcom is open to suggestions, he said. “We do want to put the incentive and the onus on industry to come forward with ideas on how they can use spectrum more efficiently, perhaps on a more dynamic basis,” he said.

Getting the data needed for better sharing may be the biggest challenge, Woolford said. “We need to obtain more real-world data, particularly if we believe that spectrum sharing is the future,” he said: “We need better coexistence modeling. We need to ensure that our models are not based on worst case upon worst case.”

“Everyone wants more spectrum,” said Dave Wright, Hewlett Packard Enterprise head-global wireless policy. “We can continue to squeeze a little bit more out of each hertz of spectrum” but that doesn’t address the need for wider channel bandwidths, he said. Wi-Fi used to focus on 20 and 40 MHz channels, “now we’re talking about the need to go to 80, 160 MHz even 320 MHz wide channels,” he said. “Unlicensed and licensed still need additional spectrum to grow -- no doubt about that,” he said.

The definition of mid-band will continue to move up the frequency range, Wright predicted. The focus on data, “everything is data, is making the higher frequencies more attractive because as we overcome the propagation and coverage issues … it allows us to carry so much more traffic because the channels tend to be so much wider,” he said. THz bands will “be very important to us, it’s a matter of when that occurs,” he said. In the 2030-2040 timeframe, when 6G launches “there’s no way to meet the needs without spectrum sharing and innovation in licensing,” Wright said.

The average smartphone customer uses 15 Gb of data per month, expected to grow to 39 by 2027, said Stuart Cooke, Global Mobile Suppliers Association chair-global spectrum team. “Now is the right time to talk about 6G and planning for the ongoing development and success of this ecosystem,” he said: “It takes such a long time to plan and discuss and earmark and then, eventually, if needed release that spectrum into the marketplace.”

Carriers will have to reuse as much of the spectrum they already have as possible for 6G, Cooke said. Industry needs to “begin that conversation now about potential additional spectrum to support 6G,” starting with spectrum between 7 and 12 GHz and the sub-THz range, he said.

High-Band Questions

Some carriers have moved to millimeter-wave spectrum for 5G, but “the performance in real-world conditions has not yet met the theory,” said Monisha Ghosh, Notre Dame professor and former FCC chief technology officer. “The question about are they a truly mobile cellular technology is still unanswered,” she said. High-band signals don’t go through walls, so you can’t serve subscribers indoors from radios outdoors, she said.

Recent research shows “handsets are very constrained,” Ghosh said: “When you have millimeter-wave you need beam forming at both ends and on the handset side there’s only a very limited number of antenna array elements that you can squeeze in.” The unlicensed 6 GHz band isn’t important to just Wi-Fi, and cellular systems will take advantage of the “huge amount of spectrum” available, Ghosh said. “Carriers need to start looking at how they can leverage that band as well,” she said.

Ghosh expects as industry moves to 6G, mid-band will remain the “most desired” spectrum. “Almost all of it is allocated,” she said. She noted that much of the high-band spectrum is already allocated to “passive scientific uses that also need to be protected,” she said. Ghosh noted as one example that the Event Horizon Telescope operates at 230 GHz.

Notebook

“The work on 6G is already well underway, and that’s a good thing,” said Ethan Lucarelli, wireless aide to Chairwoman Jessica Rosenworcel: “It’s necessary if we’re going to be able to unlock the full potential of 6G and maybe even avoid some of the pitfalls that we may have encountered with 5G. You understand that and the FCC chairwoman understands that as well.” Lucarelli said standards development is critical and the FCC is dedicating additional attention to the issue. The FCC remains focused on receivers (see 2204210049), the subject of a notice of inquiry, he said. “This won’t be fast and it won’t be easy, but it’s important and it’s worthy of our attention,” he said.