New G, new spectrum? Top spectrum considerations in 6G

At the 6G Forum, panelists said it’s time to rethink the way spectrum has been made available and deployed

Panelist at the 6G Forum seemed to agree that when thinking about the spectrum needs in 6G, it’s less about new spectrum and more about a shift in mindset. All three speakers commented that the way spectrum has been made available and the way it’s been deployed in the past won’t be possible moving forward. Specifically, they commented on the growing need to share with incumbents, as well as trends related to the type (licensed vs. unlicensed) and scale of spectrum deployments.

‘Anywhere you look, you need to share’

Monisha Ghosh,a professor of electrical engineering at the University of Notre Dame, told event attendees that more spectrum will always be needed for next generations simply because the amount of data will increase. But she continued: “The question is, does that new spectrum necessarily have to be what we’ve become used to for the G’s?” Here, she was referring to the exclusive, high-powered spectrum that operators have grown accustomed to.

“There is nothing that prevents a G from deploying in unlicensed spectrum,” Ghosh argued, adding that while unlicensed spectrum would have certain constraints and be lower power, the industry must be willing to use “whatever spectrum is available” to “maximize” connectivity for the end user.

Of course, in an unlicensed spectrum deployment, spectrum sharing becomes necessary. Perhaps it’s not what operators want to hear, but according to Jonas Wessel, the director of the Swedish Post and Telecom Authority’s resource management department, they don’t really have a choice.

“If you look more generically at the future of spectrum there is no more greenfield spectrum to be found in large amounts, so anywhere you will look, you need to share,” he said. “I would really urge anyone looking at technology development of 6G to take in sharing by design … That might lead to a situation where you’re not looking for the next IMT global band that starts from here to there, that is exclusive and will be licensed nationally through an auction … there is no more such spectrum to be found in large amounts.”

As with many aspects of 6G, artificial intelligence (AI) is expected to help here. Ghosh pointed out that an often-overlooked aspect of spectrum sharing is that not only must you share with incumbents, but you must also share with different operators in adjacent bands. “And that is where AI can really help,” she said, explaining that in 6G, data should be gathered from the phones and base stations — something that isn’t happening nearly enough today — and then application learning algorithms can be applied to better manage spectrum. “I think we could improve spectrum efficiency quite a bit,” she added.

Licensing on a smaller scale

The scale of spectrum licensing is also becoming more granular as private cellular applications continue to gain traction. These licenses are on the campus or premise level, said Wessel, referencing things like military bases, malls or airports. “And that is really going away from an operator-based type of use. All of the promises that we had in 5G, many of those are related to local, private networks, so you should look at it more on a sort of Wi-Fi scale … That granularity rather than sort of big, geographical regions,” he continued.

Ghosh provided support for this claim, pointing out that in the U.S., that is exactly how unlicensed CBRS is being used in many cases. “If you look at the use cases that are being developed … the oil refineries, the factories, the warehouses. Some of which are actually moving from Wi-Fi to a 3GPP-based system,” she said.

So, while the panelists agreed that 6G will indeed see a capacity constraint — because there is always a capacity constraint — new spectrum isn’t necessary the solution. “I still think new G, new spectrum, I’m still waiting to see,” said Ofcom’s Director of Spectrum Policy and Analysis Cristina Data. “Unless … thenew G really brings something completely different … in reality, there is the spectrum to meet the capacity of requirements of today and the short-term future. Maybe even medium-term future.”

Watch this and other 6G Forum sessions on demand here.