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More Peanut Butter and Jelly: FCC Drops the First Shoe in 5 GHz U-NII Devices Proceeding


The FCC has taken the opening steps on its proposal (ET Docket 13-49) to make available another 195 MHz of spectrum at 5 GHz for Part 15 unlicensed National Information Infrastructure (U-NII) devices. U-NII devices use “wideband digital modulation techniques to provide a wide array of high data rate mobile and fixed communications for individuals, businesses, and institutions,” the FCC has explained. In a First Report and Order (R&O) in the proceeding released on April 1, the Commission affirmed that Amateur Radio is entitled to protection from interference by such unlicensed devices.

“The Amateur Service is an allocated service entitled to interference protection within the 5 GHz spectrum,” the FCC said, “whereas U-NII devices operate under our Part 15 rules.” Amateur Radio has a secondary allocation at 5.65-5.925 GHz, including an Amateur Satellite Service uplink allocation of 5.65-5.67 GHz and a downlink allocation of 5.83-5.85 GHz.

In the R&O the FCC, among other things, extended the upper edge of the 5.725-5.825 GHz band to 5.85 GHz and consolidated the Part 15 rules “applicable to all digitally modulated devices operating across this 125 megahertz of spectrum to ensure that all such devices comply with U-NII requirements intended to protect authorized users from harmful interference,” the FCC said. The Commission did not address the use of U-NII devices in the 5.35-5.47 GHz and 5.85-5.925 GHz bands, pending additional technical analyses of those bands.

The FCC was obligated by the Middle Class Tax Relief and Job Creation Act of 2012 (PL 112-96) to begin a proceeding to amend its Part 15 rules to allow unlicensed U-NII devices to operate in the 5.35-5.47 GHz bands.

FCC Chairman Tom Wheeler called the R&O “a big win for consumers” that will offer much-needed relief to growing congestion on WiFi networks. “At the same time,” Wheeler continued, “it moves us another step closer to ending the analog-era debate of licensed vs unlicensed spectrum. In 2014, licensed and unlicensed spectrum are more complementary than competitive. They are less oil and vinegar, and more peanut butter and jelly.”

The FCC R&O turned away an ARRL suggestion that it require U-NII devices employ dynamic frequency selection (DFS) and transmit power control (TPC) throughout the 5.650-5.925 GHz segment to minimize harmful interference to Amateur Radio operations in the shared spectrum.

“ARRL’s proposal to require DFS and TPC mitigation techniques for U-NII-3 devices is not necessary, would be overly burdensome, and is not based on a demonstrated need,” the FCC R&O said. “We believe that the Amateurs have adequate access to spectrum necessary in this band, and we decline to extend the Amateur Radio allocation downwards to overlap the rest of the U-NII spectrum, as HamWAN proposes, as this request is beyond the scope of this proceeding.”

Bart Kus, AE7SJ, filed comments in the proceeding on behalf of HamWAN in the Greater Seattle Area, which describes itself as “a modern multi-megabit IP-based digital network for Amateur Radio use.”

In 1999, the Commission allocated 5.85-5.925 GHz for direct vehicle-to-vehicle and vehicle-to-roadside, or “Dedicated Short Range Communications” (DSRC). Amateurs may continue to operate in this segment, but only to the extent that they do not interfere with DSRC operations. In support of its argument that the introduction of U-NII into this segment would be premature, the ARRL has observed that “a U-NII overlay at the present time requires a good deal of compatibility analysis, none of which has been completed to date.”

In its R&O, the Commission said that cable operators and associations “support the Commission’s proposal to add the 5.825-5.85 GHz segment of the U-NII-3 band to support devices that use higher data rates.” It noted, however, that automotive and transportation-related groups expressed concern that “devices operating in the U-NII-3 band would place U-NII unwanted emissions into frequency bands used by Dedicated Short Range Communication (DSRC) Systems at levels that may cause harmful interference.”

In its comments last May, the League pointed out that there is “no legislative obligation” to make the 5.85-5.925 GHz band available for U-NII use. The ARRL traced a history of “a continuing series of overlays” to which the 5 GHz band has been subjected over the past 16 years, progressively reducing the utility of the amateur allocation there. And the League asserted that “a decision in the near term with respect to the addition of U-NII devices to the 5.85-5.925 GHz band would be premature,” a conclusion the FCC now has reached.

“Chairman Wheeler noted the need for careful study of technical analyses prior to expanding unlicensed access into the 5.85-5.925 GHz band,” ARRL Chief Executive Officer David Sumner, K1ZZ, said. “We can only hope that he will insist on this study being done before the other shoe drops in this proceeding.”





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