The FCC is trying to give a little more love to unlicensed spectrum and make sure future devices in TV white spaces work as well as they should.
In proposing changes to its Part 15 rules, the FCC said it wants to allow for more robust unlicensed service and efficient spectral use. The proposed changes would extend opportunities for "innovative" unlicensed use in the 600 MHz guard bands, Channel 37 and remaining TV bands while preventing harmful interference to licensed services, according to FCC Chairman Tom Wheeler.
Not everyone is as enthusiastic, however. Before the commission's vote at its September open meeting earlier his week, FCC Commissioner Ajit Pai, for one, expressed concern that permitting white space devices to operate in the guard bands, at the power levels and bandwidths proposed, might impair the adjacent licensed spectrum. He said the FCC's own analysis shows that operating white space devices under the Notice of Proposed Rulemaking's (NPRM) proposed configurations could, in the worst-case scenarios, cause harmful interference to wireless devices whenever they're within even 7 meters of each other. That would mean that white space devices could interfere with wireless handsets whenever they're in the same room, he said.
It could be worse than that, he added. The FCC's analysis assumes that wireless handsets will use additional filtering above and beyond the 3GPP standard. "It also assumes that there will be at least a 3 MHz frequency separation between white space devices and licensed wireless services--yet the guard bands the FCC adopted in the Incentive Auction Order won't be large enough in every recovery scenario to provide that amount of separation," he said in a statement approving in part and concurring in part with the commission's decision to amend the rules.
But Commissioner Jessica Rosenworcel pointed out how three decades ago, the commission was looking at what to do for airwaves that were designated for industrial, scientific and medical (ISM) uses. The spectrum once deemed as "garbage bands" ultimately ended up being spectrum where Wi-Fi was born. Today, nearly one-half of all wireless data connections in the U.S. are offloaded onto unlicensed spectrum.
Services striving for space in the 600 MHz band, such as wireless microphones, low power television, medical telemetry and radio astronomy deserve attention under the law, she said, adding that some of the same smart engineering minds that sparked the invention of Wi-Fi 30 years ago can find ways to make it all work in the future.
Google (NASDAQ: GOOG) and Microsoft (NASDAQ: MSFT) have been big proponents of technical rules enabling the use of unlicensed devices in the 600 MHz broadcast TV spectrum that will be auctioned next year. Several Google and Microsoft representatives held meetings with FCC commissioners and staff ahead of this week's open meeting.
Others raise concerns that permitting unlicensed operations in the 600 MHz band will cause interference with licensed mobile services. Qualcomm (NASDAQ:QCOM), for example, has argued that unlicensed operations and wireless microphones in the 600 MHz duplex gap and guard bands should be allowed only if it can be demonstrated that such operations won't cause interference to licensed mobile broadband services or remaining TV broadcast stations.
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