Beyond The FCC's 700 MHz

The January auction isn't the only coveted spectrum that could deliver new wireless services.
Posted August 27, 2007

Roy Mark

With an unprecedented demand for mobile devices and services expected in the near future, the scramble is on for the one thing all cell phones, PDAs, iPhones and other wireless devices need: spectrum.

But outside of the much anticipated January 700 MHz auction, the Federal Communications Commission (FCC) isn't planning on selling anymore spectrum at this time. Tech hopes to change that with several proposals now pending before the agency.

From the interference buffer zones between television stations to space that some claim is underutilized and could be used for wireless broadband services, new "smart" radio technology and other innovative ideas are prompting the FCC to reevaluate its spectrum policies.

White spaces fall into gray regulatory area

Although broadcasters are allocated hundreds of megahertz of spectrum in every U.S. television market, significant chunks are unused, serving as buffers against interference from other channels. In Boston and Chicago, for instance, almost 50 MHz is fallow.

Technology companies such as Microsoft and Google hope to use these interference buffer zones, known as "white spaces," to develop both licensed and unlicensed wireless devices and services. Licensed use could include delivering wireless broadband.

The interference buffers were once considered necessary because older technologies required more space between the television channels. But the White Spaces Coalition, which includes Microsoft, Dell and HP, claims new technology allows for the use of the space between the channels without interference to the broadcasters.

According to the coalition, technology exists that scans for TV channels in use and jumps to unused spectrum in the white spaces. To prove the point, Microsoft in March submitted a prototype model to the FCC.

Unfortunately for the coalition, the prototype failed the initial FCC tests, because it did "not consistently sense or detect TV broadcast or wireless microphone signals," the FCC report

Microsoft claims the device tested by the FCC was broken and a second device, also in the FCC labs, works well.

"Coalition members are encouraged that FCC engineers did not find fault with our operating parameters and remain confident that unlicensed television spectrum can be used without interference," the group said in a statement. "In fact, in its report, the FCC stated that 'the bench test results indicate that under laboratory conditions, this device is generally able to reliably detect DTV signals.'"

The National Association of Broadcasters (NAB) pointed to the FCC report as proof the device doesn't work.

"FCC testing results confirm what NAB...and others have long contended: that the portable, unlicensed devices proposed by high-tech firms can't make the transition from theory to actuality without compromising interference-free television reception," NAB Executive Vice President Dennis Wharton said in a statement.

To the disappointment of the NAB, however, the FCC said it was still open to the possibilities of using white space spectrum. "The devices we have tested represent an initial effort and do not necessarily represent the full capabilities that might be developed with sufficient time and resources," the report states.

Even before Microsoft submitted its prototype, the FCC was interested in white spaces technology, contending that broadcasters' original fears of interference are perhaps unjustified in a technological age that includes smart radio transmitters and receivers.

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