Microsoft and Philips have both previously pushed for the use of white space frequencies (those unused chunks in the television spectrum), and now have filed again their case with the Federal Communications Commission (FCC). Analog TV uses fixed frequencies in the U.S., also known as channels. Between these there are "spaces" which were originally designed to prevent interference between adjacent television channels. In addition, the upcoming switchover to digital television may also free up large areas between 54MHz and 698MHz.

Microsoft and Philips want the FCC to allow the use of a generation of new devices that can access the Internet using unlicensed spectrum (white spaces). They both have submitted prototypes earlier this year for FCC testing, but the Federal Communications Commission has alleged that they did not work properly. Its Office of Engineering and Technology, or OET, said that the devices failed to swiftly track and avoid interference with licensed broadcasts.

"The sample prototype white space devices submitted to the commission for initial evaluation do not consistently sense or detect TV broadcast or wireless microphone signals," the Office of Engineering and Technology has alleged in early August. "Our tests also found that the transmitter in [a] prototype device is capable of causing interference to TV broadcasting and wireless microphones," they claimed. However, Microsoft has found that the prototype which has undergone testing was damaged, and the OET did not use the functioning backup prototype in testing.

In the latest filing, both companies claim they now have conducted their own, successful white-spaces prototype testing and are asking the OET to retest the new devices. They are hoping to get a favorable answer and a subsequent decision soon. Microsoft and Philips claim in the filing they had conducted over 1,000 measurements in New York and California and the prototype devices were able to detect over-the-air TV signals at very low power levels with 100 percent accuracy.

"What the results of these tests mean is that with we can determine with great certainty whether a TV channel is vacant or occupied," said Ed Thomas, the technology policy adviser and partner at Harris Wiltshire & Grannis, the law firm representing the White Space Coalition. "And if the channel is occupied, the device won't transmit any signals over that channel."

This White Spaces Coalition is made up of Microsoft, Google, Dell, HP, Intel, Philips, Earthlink, and Samsung Electro-Mechanics. They want to deliver high speed (broadband) internet access to consumers via existing 'white space' in unused analog television frequencies. Their archenemies are TV companies, which complained to the FCC that there is a "potential for countless instances of interference to reception of digital-television signals." More precisely, Walt Disney Co.'s ABC television network filed comments to the white space project with the FCC pushing for the rejection of the White Spaces Coalition's proposals.

Analog television frequencies, which are between the 54 MHz and 698 MHz, are to be freed up under a United States Senate decision in February 2009.