As part of its rules for the upcoming 600 MHz incentive auction, the FCC outlined new rules for unlicensed activities that the agency said are "designed to allow for more robust unlicensed use and to promote spectral efficiency in the 600 MHz band." However, the agency's rules immediately drew complaints from the likes of AT&T and the National Association of Broadcasters, which generally argued the FCC's rules will create more interference in the bands.
In its comments on the topic, AT&T praised the FCC for moving forward on the auction. But the carrier took issue with several elements of the FCC's plan, including the agency's move to permit unlicensed uses in the duplex gap in the 600 MHz band. The duplex gap is the space between the licensed uplink and downlink channels in the 600 MHz band. AT&T said allowing unlicensed transmissions in the duplex gap creates the potential for interference in the adjacent licensed allocations.
"The wireless industry -- the very entities that are being asked to spend billions of dollars to make the auction a success -- conducted and submitted testing that conclusively demonstrated this potential [for interference]," AT&T said. "The Commission rejected that testing, building guard bands that will effectively interfere with licensed allocations, not protect them, as required by statute."
In a post on the topic, wireless industry trade group CTIA raised similar concerns.
Separately, the NAB, too, raised concerns about interference, noting that the FCC's band plan for the auction is "destined for decades of interference disputes." NAB is the trade group that represents TV broadcasters, which are expected to give up a portion of their 600 MHz spectrum holdings so that wireless carriers and others can bid on them in the 600 MHz incentive auction, scheduled to start early next year.
FCC Commissioner Ajit Pai acknowledged the interference concerns, noting that he did vote to approve the rules but held some reservations. "Indeed, the record shows that even a 5 percent loss of spectrum capacity due to interference from guard band operations will lower spectrum values by 9 percent. A 20 percent impairment will lower them by 43 percent," he wrote in a statement following the FCC's vote on the rules.
On the opposite side of the issue stand Wi-Fi proponents like the Wi-Fi Alliance, WiFiForward and Google, which has consistently pushed the FCC to release more spectrum for unlicensed use. Already, Google is one of the companies that manages a database for TV white spaces.
Indeed, in a filing with the FCC just prior to the release of the agency's incentive auction rules, Google said it continues to work to improve its TV white space (TVWS) database. "Google and other TVWS database operators and device manufacturers are working collaboratively with Commission staff and NAB to further refine TVWS processes and address any remaining concerns," Google said. "For example, Google supports the efforts of NAB and TVWS equipment manufacturers to minimize and/or eliminate human involvement for location determination on TVWS equipment. Google is also an active participant in the White Space Database Administrator Group's work with the FCC to harmonize database records and improve data hygiene."
Previously, NAB and others have raised concerns about existing TV white space operations as haphazard and unorganized.
In its new incentive auction rules for 600 MHz unlicensed operations, the FCC said it will provide technical parameters for "fixed and personal/portable white space devices to operate in the 600 MHz band, including the duplex gap and guard bands, and channel 37 on a shared non-interference basis with medical telemetry and radio astronomy." The agency also said it will allow sharing of spectrum between white space devices and wireless microphones.
Further, the FCC said it will expand the location and frequency information in white space databases and institute "transition periods" for the certification, manufacturing and marketing of white space devices and wireless microphones that comply with new rules.
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