Verizon recently completed a pre-standards 6G test call using spectrum in the 7 GHz band, however CTO Yago Tenorio told an audience at this week’s Brooklyn AI-Native 6G Summit that the trial showed considerable work still needed to be done before the use of spectrum in that band is ready to support commercial deployments.

Verizon and network partner Ericsson conducted the test call using 400-megahertz of spectrum in the 7 GHz band across a single channel that was beamed from a base station installed near a commercial Verizon site in Concord, California. The signal was transmitted to user equipment housed within a 12-by-8-foot mobile enclosure lined with wall and window materials of various thicknesses and materials to “enable differentiated testing of indoor coverage.”

Tenorio told this week’s audience that while the test was a success, it highlighted a stark difference between the performance of wireless technology operating in the 7 GHz band and the 3.5 GHz band (C-band) that underpins the carrier’s 5G “ultrawideband” service.

“The conclusion, apart from the relevance of a pre-standard call in the field, the conclusion was not super encouraging,” Tenorio said. “Sever-gig versus 3.5, not surprisingly, have some challenges in penetrating buildings. It doesn't mean that we can't sort it out. It means that a lot more work needs to happen on more density in the antenna, higher active element number, of course higher output power, higher EIRP (effective isotropic radiated power) limits. All that need to be true and still there's probably challenges for seven to match the C-band footprint.”

That basic challenge relates to the transmission characteristics of spectrum, with lower bands able to travel further and more easily through obstacles than higher bands when beamed at the same power levels. However, there remains more spectrum available in higher bands, which means it can support more overall traffic and provide higher speeds, but does require a denser antenna infrastructure architecture and the use of more complex multiple-input, multiple-output (MIMO) antenna designs.

U.S. regulators, including the Federal Communications Commission (FCC) are looking at several new spectrum bands that it wants to free up for use by telecom operators in support of 6G services. This includes spectrum in the 1.675 GHz, 2.7 GHz, 4 GHz, and 7 GHz bands, much of which is currently held by federal agencies.

Arielle Roth, assistant secretary of commerce for communications and information Administrator at the National Telecommunications and Information Administration (NTIA), told an audience at the same conference this week that those bands were being offered up to counter other countries wanting to ferment 6G standards in the 6 GHz band.

“Those bands … combined with what the FCC is doing on the upper C-band are really going to be critical to countering the efforts by some of our adversaries to locate the future of 6G in the 6 GHz band, establishing that those opportunities for large swaths, large channel sizes is really something that we're focused on, and we're working in collaboration with federal agency partners across the United States government,” Roth said.

MmWave gaining steam

While Tenorio expressed challenges with the use of higher spectrum bands in commercial settings, he did note those bands remain core to next-generation wireless services as they evolve from 5G to 6G. Tenorio said the use of millimeter-wave (mmWave) spectrum bands “makes a big difference” for customers in “hot spot” environments like stadiums.

MmWave spectrum bands are generally considered those above 10 GHz. Verizon currently holds licenses for around 1,700-megahertz of spectrum across various mmWave bands.

Tenorio noted Verizon’s deep mmWave spectrum portfolio would help drive new fixed-wireless access (FWA) opportunities as recently touted by Verizon CEO Dan Schulman.

“My boss was very clear on the earnings call early last week,” Tenorio said of Schulman’s recent proclamation. “We believe that we found a second life for millimeter wave to fuel our FWA ambitions. So that will be a role that I see in the long term will still be there. So it applies to 5G and 6G at the same time … you'll hear more about that shortly.”

Schulman during Verizon’s recent earnings call said the carrier has developed an “innovative solution” that will allow it to use its approximately 1,700-megahertz of mmWave spectrum holdings to provide 1 Gb/s FWA service in metro areas across the country. This service is expected to serve up to 15 million connections complementing the carrier’s already growing fiber-based broadband expansion that is set to hit 50 million customers passed over the next several years.

The executive did not expand on the technical innovation of the new offering, but the carrier did recently move to acquire fixed-wireless broadband provider Starry to expand the carrier’s multidwelling unit (MDU) aspirations. Verizon has also been trialing various mmWave-based network technologies over the past several years.

Schulman said that updated FWA service would launch before the end of this year and sets the carrier up to extend its still-standing FWA ambition to serve up to nine million connections by 2028.

“The truth of the matter is now that we have a high-speed FWA offer, we'll go well beyond that now because we have a lot more capabilities. We have a lot more capacity to do that,” Schulman said.