6G Will Be Built on Shared Spectrum, Industry Panel Warns

The NTIA must identify at least 500MHz of spectrum for commercial auction before 2030 to support 5G and 6G wireless broadband in the US, and much of that spectrum will have to be shared with existing users rather than cleared. That reality framed a 6G Forum panel this week featuring representatives from the NTIA, AT&T, LitePoint and the Dynamic Spectrum Alliance, who agreed that spectrum sharing is set to become a central element of 6G planning as demand grows for increasingly scarce resources.

Legislation sets an even broader US goal of 800MHz by 2034. Studies already cover several candidate bands, including portions of the 1.6GHz, 2.7GHz, 4.4GHz and 7GHz ranges, according to Derek Khlopin, the NTIA's deputy associate administrator for spectrum.

Why can't the spectrum simply be cleared?

Making spectrum available does not mean it can immediately be emptied of its current occupants. Certain federal systems could remain in bands "for a significant amount of time," Khlopin said, requiring ongoing sharing or other protections.

"There will be more sharing necessary because the demands certainly aren't stopping, not just from the mobile community, but from other spectrum users as well on the commercial side," he said.

Khlopin described the likely outcome as "a bit of a mixed bag": some systems may move to new frequencies, while others stay put and are accommodated through static exclusion zones or dynamic access arrangements. He cited CBRS, the 3.5GHz shared-access framework, as a "great model," and suggested better data and AI scheduling tools could make sharing more efficient over time.

What does sharing do to device testing?

For mobile operators, shared spectrum must become predictable enough to plan networks around. Khushboo Kalyani, product marketing manager at test equipment vendor LitePoint, said regulators and standards bodies need to define interference conditions — including power limits, signal leakage, waveforms and frequency offsets — so device makers and test vendors can evaluate equipment against them.

"There could be 100 different real-world situations that a device comes through. You essentially cannot test against that," Kalyani said. Instead, the industry could select test cases that characterize performance under shared or interfering conditions.

That challenge compounds as 6G adds bands, sharing arrangements, modulation schemes and antenna configurations. Kalyani warned the combinations could multiply the test matrix, extending development time and raising manufacturing costs. "You're essentially now going to be testing a combination of combinations," she said. She expects the industry to settle on practical subsets of scenarios rather than trying to test every possible configuration.

Can 5G and 6G share the same bands?

The panel also turned to sharing between generations of cellular technology. Milap Majmundar, AVP of emerging network, spectrum technologies and standards at AT&T Labs, said newer multi-RAT spectrum sharing (MRSS) technology could avoid the shortcomings that weighed down 4G/5G dynamic spectrum sharing (DSS).

DSS carried overhead from control channels and forced 5G transmissions to work around LTE reference signals. New Radio does not carry the same burden. "[New Radio/NR] does not have these fixed common reference signals," Majmundar said, giving the newer air interface greater flexibility.

"I'm actually quite optimistic that we will be able to make, as an industry, 5G/6G MRSS to be much more efficient than what we had with 4G/5G DSS," he said.

Where does Wi-Fi fit in?

Martha Suarez, president of the Dynamic Spectrum Alliance, argued that 6G planning should extend beyond cellular and incorporate Wi-Fi and non-terrestrial networks as well.

"I agree with the concept that 6G should have sharing as part of the concept itself. I think it's harder now to find exclusive bands for everything," she said, adding that spectrum could be shared across applications depending on deployment and local needs.

Suarez pointed to the UK's proposed approach for upper 6GHz, under which mobile operators would have access when they need the band and Wi-Fi could use it when it is idle. Such models could help balance investment certainty with more intensive spectrum use. "Those models could also be considered," she said.

She also welcomed the US decision to open the full 6GHz band for Wi-Fi and encouraged other countries to weigh the benefits of that approach. "Europe has a somewhat different path, and they think that they will need part of the upper 6GHz band for future networks. But we are encouraging them to have some type of sharing," Suarez said. European regulators have in fact favored mobile operators over Wi-Fi for upper 6GHz.

With the 2030 auction deadline approaching and no prospect of clean, exclusive allocations at scale, the sharing frameworks discussed at the forum are likely to move from technical debate to regulatory design well before the first 6G networks appear.