The FCC voted today to issue a Notice of Proposed Rulemaking and Order looking toward issuing licenses for frequencies above 95 GHz. That’s GigaHertz, not MegaHertz – way up there, beyond the highest frequencies that are commonly used today, at least by the private sector.
Historically, frequencies this high were not considered useful for communication transmission. But the radio art has advanced quickly; and Amateurs, who make it their business to advance the state of the art, have been allowed to operate above 95 GHz for years. Today, commercial inventors and entrepreneurs are seriously at work developing ways to exploit higher and higher frequencies. The amount of available bandwidth is enormous; so if the high frequencies can be used, the possibilities for ever-faster wireless broadband and backhaul speeds are significant.
The FCC has proposed to authorize three types of operations: regular licensing, unlicensed systems, and experimental licensing. The structure for licensed systems would be based on the existing system for the 70, 80, and 90 GHz bands, where licenses for point-to-point systems will be issued to anyone who wants them, all for nationwide operation, and without limit on the number of licenses available. All operators will be required to register each of their point-to-point links with one or more private database managers, with protection of links from interference given on a first-come, first-served basis. In other words, each new link must protect those that were registered earlier. The amount of spectrum the FCC hopes to open up for licensed use is 102.2 GHz.
Unlicensed systems would be regulated similarly to existing regulations for the 60 GHz band. The FCC anticipates that transmission range will be limited; that’s because signals so high in frequency, which in turn have very short wavelengths, tend to be absorbed or blocked by atmospheric particles. This characteristic should allow many systems to co-exist without interfering with one another. As much as 15.2 GHz of spectrum is proposed for unlicensed use.
The FCC also proposes to issue experimental licenses from 95 GHz up to 3,000 GHz (3 TeraHertz). All operation would be conditioned on not interfering with other systems, presumably both licensed and unlicensed. The FCC proposes more flexibility for these licenses than it has allowed for experimental licenses in the past, including a longer than normal license term and the ability to transfer experimental licenses.
Finally, the FCC is proposing to permit the sale of new equipment during market trials, contrary to the existing heavy restrictions against sale before operating rules are adopted and before equipment receives certification.
While the prospects for exploitation of ever-higher frequencies are exciting, it appears that the FCC is assuming for now that uses will be limited to relatively short, straight-line, point-to-point communications and very short-range Wi-Fi-like systems. However, we are aware of research currently in progress which has demonstrated that propagation is not limited to straight-line paths and that frequencies above 95 GHz may bend around corners to some degree. As technology develops, it will be interesting to see what applications are the most successful and what traditional technical assumptions may require additional analysis.
Meanwhile, the FCC has also voted to propose rules to implement Section 7 of the Communications Act, which requires the FCC to act on petitions or applications for new technologies and services within one year of receipt. The FCC proposes that its Office of Engineering and Technology (OET) make a recommendation within 90 days as to whether a petition for approval of a new technology should be put on a one-year track or processed normally. The full Commission will review the recommendation and decide whether to initiate a formal rulemaking.
We will be happy to answer any questions about the FCC’s proposals and to help you file written comments or meet with the FCC’s staff to present your ideas. Contact Peter Tannenwald at firstname.lastname@example.org.