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FCC Opens New 5 GHz Spectrum for Unlicensed Devices

On March 31 the FCC adopted a First Report and Order (R&O) which modified the rules for operations of Unlicensed National Information Infrastructure (U-NII) devices in the 5 GHz band. These new rules open up 25 MHz of new spectrum for 5 GHz unlicensed devices, allow outdoor operation of U-NII devices on spectrum where indoor-only operation was previously allowed, and harmonize rules across the U-NII bands, allowing increased power in some bands.

These new rules should greatly increase the utility of the 5 GHz bands. As I've asserted before, higher data speeds require higher frequencies. In my opinion, this R&O, as well as the additional frequencies mentioned in the R&O, could do more to increase the availability of wireless broadband than the much touted auction of UHF TV's 600 MHz spectrum.

The 5 GHz unlicensed band isn't well suited to wide area point-to-multipoint coverage, although the R&O continues to allow point-to-point links using larger dishes with the EIRP needed to cover long paths.

The National Cable and Telecommunications Association was one of the supporters of the FCC's revised 5 GHz rules. The 5 GHz spectrum is excellent for delivering high data rates over short distances with closely spaced access points which require a broadband connection to the Internet. Cable companies have the infrastructure to deliver 5 GHz broadband connectivity to consumers at a cost far less than that for cellular wireless broadband and provide much higher speeds. This is good news for consumers, as it will increase wireless broadband competition and that should lower prices.

The new rules also change operational conditions in connection with the 5 GHz spectrum shared with Globalstar. Previously unlicensed operations were only permitted indoor; now outdoor transmissions are okay, so long as radiation more than 30 degrees above the horizon is limited.

U-NII operations are also now allowed in the 5825-5850 MHz band. This is spectrum shared with amateur radio operators and federal government radiolocation applications.

Some of the 5 GHz band is shared with radar operations and there have been several cases where the FCC has cited wireless operators for interference with Terminal Doppler Weather Radar (TDWR) systems and other radars operating in the 5.25-5.35 GHz and 5.470-5.725 GHz band. The systems that caused this interference were authorized for use on frequencies outside these two bands, but had been modified to operate within the bands shared with TDWR. The new R&O modifies rules for dynamic frequency selection (DFS) compliance in 5 GHz devices to reduce the chance of such interference to radar systems. In addition, 5 GHz devices designed for operation outside the spectrum shared with radar will have to have additional security to prevent them from being modified to operate within spectrum where DFS is required.

To learn more about the new rules and additional spectrum that may be allocated for unlicensed use in the 5 GHz, see Report and Order (FCC 14-30) on revision of Part 15 of the Commission's rules to permit Unlicensed National Information and Infrastructure (U-NII) Devices in the 5 GHz band.

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.