Spectrum Horizon Order May Not Fix Expected Shortfall of Wi-Fi Spectrum

The FCC identified the four band segments Friday to be allocated for unlicensed use in spectrum above 95 GHz in an order scheduled for a vote at the March 15 commissioners' meeting. The identity of the bands, which Chairman Ajit Pai discussed in a Thursday blog post (see 1902210048), had been the source of some confusion. The segments are 116-123, 174.8-182, 185-190 and 244-246 GHz, according to the draft order.

Rules for unlicensed use there are to be based on those in place for unlicensed use of the 57-71 GHz band. Industry officials welcomed the proposal. The Wi-Fi Alliance said it won't solve a predicted shortfall in unlicensed spectrum.

“Bands once thought of as unusable are now well within the range of modern communications systems,” the draft argues. “We take steps to provide new opportunities for innovators and experimenters to push those boundaries even further, and to develop new equipment and applications for spectrum between 95 GHz and 3 THz.”

The Wi-Fi Alliance welcomes the rules, said Alex Roytblat, senior director-regulatory affairs. The alliance “expects the future will present opportunities to employ spectrum above 95 GHz for Wi-Fi and other technologies that use unlicensed spectrum,” he said. But “because of the technical challenges of deploying consumer devices at such high frequencies, this spectrum cannot be used today to alleviate the existing and projected spectrum shortage," he said: "The relief necessary to meet current and near-term spectrum capacity requirements must come primarily from mid-band spectrum.” Roytblat stressed the importance of the 6 GHz item before the commission.

Broad experimental license grants and very permissive unlicensed rules make a lot of sense for the high-band spectrum, said Doug Brake, director-broadband and spectrum policy at the Information Technology and Innovation Foundation. Spectrum above 95 GHz “starts to behave so differently compared to the lower bands we’re used to, plus exploration of communications use of these bands is so nascent,” Brake said. Important is “getting some basic ground rules out there for those who want to innovate without stepping on the passive uses in these bands,” he said.

Wireless ISP Association members also welcome the rules, said President Claude Aiken. “WISPs already are making significant use of 60 GHz unlicensed spectrum to deliver high-speed broadband,” he said. “Freeing up additional unlicensed spectrum above 95 GHz will provide the market certainty necessary to enable the development of next-generation wireless equipment.”

The FCC is putting off for later consideration proposals in last year’s NPRM for licensed use of the spectrum. “Although these proposals were designed to ensure that we would not constrain the ways in which the bands above 95 GHz can develop or foreclose innovation through too-rigid service rules, several commenters raised concerns about the risks of adopting service rules for these frequencies,” the FCC says. “We continue to believe that the frequencies above 95 GHz are potentially suitable for licensed use.”

Testing

The bands already see some use worldwide, the FCC says.

Brown University and New York University's Tandon School are doing propagation measurements in frequencies as high as 400 GHz, the draft says. Boeing and Raytheon are testing antennas and radar receivers at frequencies near 100 GHz. “In 2008, Japan’s NTT used wireless links in the 120 GHz band to provide live TV coverage of the 2008 Beijing Olympics.”

All uses of the spectrum mustn’t interfere with other operations already in place, the draft says: “We expect to gain knowledge from real world operation that will inform the Commission’s future consideration of more expansive use, including non-experimental licensed uses, in these spectrum bands.”

The order would create a subpart to Part 5 experimental radio service for spectrum horizons experimental radio licenses. “With their low barriers to entry and minimal costs to obtain, experimental licenses are a proven engine for innovation and offer extraordinary flexibility in system design and technical specifications (such as frequency range, power, and emissions) while ensuring that no harmful interference is caused to existing authorized users,” the FCC says.

The National Academy of Sciences’ Committee on Radio Frequencies and the National Radio Astronomy Observatory sought to exclude certain bands from experimental licensing, where passive services have primary status, the regulator says. “A blanket prohibition is not necessary,” the FCC argues: “All bands between 95 GHz and 275 GHz are allocated on a shared basis for federal and non-federal use. Above 275 GHz, there are no allocations, but a number of bands are identified for use by passive services in footnote US 565. Spectrum Horizons Licenses in this range will only be granted on a non-interfering basis, only following coordination with federal users.” The FCC similarly dismisses arguments by ARRL, representing amateur radio operators, against licenses in two bands with primary amateur radio allocations -- 134-136 and 248-250 GHz.

The draft proposes 10-year experimental licenses, the longest terms available, which will “encourage entrepreneurs to invest in this largely untested spectrum, and yield more useful long-term information and data in support of subsequent rulemaking activity or waiver requests for operations in these bands.” It calls for liberal rules for device sales under its experimental licensing restrictions: “These rules diverge from the existing market trial rules which only permit devices to be sold to other holders of experimental licenses or to lease devices to trial participants, by allowing direct sales to members of the general public.”