The FCC is set to consider an agenda item at its next open commission meeting on Feb. 22 that proposes to open up gobs of new spectrum above 95 GHz.
If approved, the Notice of Proposed Rulemaking would seek comment on adopting rules for fixed point-to-point use of up to 102.2 gigahertz of spectrum in various bands, as well as making up to 15.2 gigahertz of spectrum available for unlicensed use in several band segments and creating a new category of experimental licenses for the 95 GHz to 3 THz range.
“The time has come to let go of the reins with respect to these very high bands and start empowering U.S. innovators to test their ideas,” said FCC Chairman Ajit Pai in a blog post. “That’s why I’ve circulated my Spectrum Horizons proposal to open up this spectrum and create a new testbed for technological progress.”
Recognizing that most of the spectrum in the third category is currently shared between federal government agencies and non-federal users, Pai said the plan would continue close coordination with the executive branch.
“If this Notice of Proposed Rulemaking is approved at our February meeting, I hope to get good public feedback on these ideas and then act quickly,” he said. “If we broaden our nation’s spectrum horizons, we’ll keep the United States in the lead when it comes to technological innovation.”
Some industry stakeholders already have filed comments in the Spectrum Frontiers docket regarding spectrum above 95 GHz, including Marcus Spectrum Solutions, which advocates for large contiguous spectrum blocks for terrestrial fixed service.
Interestingly, the commission traces the first substantive investigation into the potential use of the higher band spectrum to a 1994 proceeding that explored opening portions of the millimeter wave bands above 40 GHz for commercial development. In 2003, the commission initiated a proceeding that led to the adoption of provisions for licensed fixed operations in the 71-76, 81-86 and 92-95 GHz bands and provisions for unlicensed operation in the 92-95 GHz band that were limited to indoor use.
The FCC also noted that both industry and academia have shown interest in the bands above 95 GHz, citing projects by Brown University, New York University's Tandon School, Raytheon and Boeing. Elsewhere, Japan’s NTT used a 120 GHz band wireless link in a 1 km transmission trial to provide live TV coverage for the 2008 Beijing Olympics, and Japan in 2014 revised its radio regulations to allocate an 18 gigahertz-wide band at 116 GHz to 134 GHz to accommodate such a service.
Last year, Nokia said it was joining with other technology leaders, including Virginia Diodes and Keysight Technologies, in becoming founding members of the mmWave Coalition. The coalition was formed to advocate a regulatory framework to the FCC, other U.S. government agencies, and the International Telecommunications Union to permit the use of radio frequencies above 95 GHz.
Nokia even brought up the possibility of 6G. “The mmWave Coalition member companies are united in the objective of removing regulatory barriers to technologies and using frequencies ranging from 95 GHz to 450 GHz,” wrote Nokia’s Paul Norkus at the time. “While 5G and possibly even 6G(!) might look at these as potential frequency bands to use, the Coalition is not limiting itself to supporting any particular use or technology. Instead, it is working to create a regulatory structure for these frequencies that would encompass all technologies and all possible uses, limited only by the constraints of physics, innovation and the imagination.”
The FCC noted that the technologies that ultimately are deployed above 95 GHz will depend on the propagation properties of the spectrum in which those technologies will operate. Millimeter wave signals are affected by oxygen and water vapor within the atmosphere, although the amount of signal attenuation varies with frequency and other factors. Attenuation caused by oxygen is significant throughout the millimeter wave spectrum but increases dramatically around 60 GHz, 120 GHz and 183 GHz, the FCC said.