The FCC's move to release more 5 GHz frequencies for gigabit Wi-Fi use reflects efforts to develop and employ spectrum-sharing techniques to open up encumbered frequencies. It also highlights the ongoing battle between parties advocating for licensed vs. unlicensed spectrum allocations.
The notice of proposed rulemaking (NPRM) would revise Part 15 rules that permit Unlicensed National Information Infrastructure (U-NII) devices in the 5 GHz band.
U-NII devices today operate in 555 megahertz of spectrum in the 5.150-5.350 GHz (200 MHz) and 5.470-5.825 GHz (355 MHZ) bands. The NPRM would open up 195 MHz of additional spectrum in the heavily encumbered 5350-5470 MHz (120 MHz) and 5850-5925 (75 MHz) MHz bands, with the use of spectrum-sharing technologies envisioned as one way to make the spectrum available to private as well as federal entities.
Currently Part 15 rules break up the spectrum into several blocks with their own sets of requirements. The NPRM would harmonize the rules so new technologies--such as "Gigabit Wi-Fi" based on the 802.11ac standard--employing wide bandwidth have the flexibility to operate across the spectrum. The proposed rules would also streamline certification for equipment using the spectrum.
"This NPRM would accelerate the growth and expansion of Wi-Fi technology and introduce a new generation of wider bandwidth and higher data rate devices that will offer consumers faster speeds and reduce congestion at Wi-Fi hotspots," said Julius Knapp, chief, office of engineering and technology. "The NPRM also provides the unique opportunity for the commission to more fully study technologies and techniques that allow unlicensed devices to share spectrum with incumbent federal and non-federal services."
The FCC envisions devices using this spectrum would be equipped with sensing technologies allowing them to detect, for instance, if certain spectrum is being used by federal radar system, prompting the device to shift to unoccupied spectrum in the same location. The FCC is working with the National Telecommunications and Information Administration, federal agencies and the private sector to assess the use of such techniques to enable spectrum-sharing.
However, the FCC's move has raised red flags among automakers and the U.S. Department of Transportation, which have been testing new connected car technologies designed to prevent accidents using 5.9 GHz spectrum, which is part of the 195 MHz the FCC wants to open up for Wi-Fi. The commission will solicit public comments regarding its 5 GHz plan over the coming months.
"The commission's proposals build upon the initial findings in NTIA's recent 5 GHz study in which we evaluated known and proposed spectrum sharing technologies and the risks to federal users if unlicensed devices were allowed to operate in the 5350-5470 MHz and 5850-5925 MHz bands. I am pleased that the FCC is also addressing in this proceeding key technical and enforcement issues in other 5 GHz band segments, including those in which interference problems have arisen and to which additional federal operations could be relocated from other bands," said Lawrence Strickling, assistant secretary of commerce for communications and information and NTIA administrator.
The FCC's effort to release 5 GHz spectrum for unlicensed use also generated comments from parties calling for the allocation of more unencumbered spectrum for licensed use.
The 5 GHz NPRM "does not mean we can be complacent and stop advocating for additional federal spectrum to be auctioned for exclusive-use licenses. The federal government, specifically the executive branch, needs to evaluate its spectrum usage with the goal of relinquishing bandwidth for exclusive and flexible private-sector uses," said Robert McDowell, a Republican FCC commissioner.
"Spectrum sharing and the auctioning of exclusive-use licenses are not equivalent," he added.
AT&T (NYSE:T) posted a comment on its Public Policy blog noting that it "has long recognized the value of unlicensed spectrum technologies, such as Wi-Fi," and added the company has build "the the nation's largest Wi-Fi network."
However, AT&T also made a push for expanded availability of licensed spectrum, saying spectrum that is not ideal for mobile broadband should be made available for unlicensed use.
"Clearing and auctioning spectrum below 3 GHz for exclusive, licensed use must remain a priority for the U.S. government as we continue to seek ways to address the growing spectrum crunch and the ever growing demand for mobile broadband services. However, freeing up spectrum for unlicensed uses can also play an important role in more fully utilizing spectrum that is not ideal for mobile broadband use," said AT&T.
FCC Chairman Julius Genachowski announced the FCC's plans to free up more 5GHz spectrum for unlicensed use last month during the 2013 International CES event in Las Vegas. The 195 MHz slated to be opened represents the largest block of unlicensed spectrum made available for Wi-Fi since 2003, when capacity in the 5 GHz band was doubled.
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