After last summer’s unsuccessful tests of proposed devices from Microsoft and Philips, members of the White Spaces Coalition of technology companies have focused on proving the ability to develop white spaces devices (WSDs) that will permit unlicensed devices such as broadband Internet to operate without interfering with broadcast television and wireless microphones. In a Dec. 5 filing with the FCC, coalition member Google provided results of internal testing of two technologies said to accomplish this goal.
As an Internet-based company, Google’s ex parte filing caught many observers by surprise. According to the document filed with the FCC, both of Google’s experimental technology devices used repurposed equipment that reliably detected DTV signals well below the noise floor and would turn off the unlicensed device in the presence of those signals. Similarly, Google demonstrated interference mitigation with short-burst transmissions such as those associated with wireless microphones.
In recent weeks, Motorola and a California start-up firm called Adaptrum have presented their own WSD hardware to the FCC for testing. In addition, a Dec. 5 letter to the FCC on behalf of Philips and Microsoft confirmed that both companies have made arrangements to submit updated versions of their own devices to the FCC Office of Engineering and Technology for inclusion in the next round of testing.
Wireless manufacturer Shure, a staunch supporter of the massive installed base of conventional wireless systems operating in various portions of the UHF spectrum under Part 74, have filed a proposed test plan for WSD devices. While it is the FCC that will determine the test conditions, Shure spokesperson Mark Brunner said that the next round of white space prototype device testing will potentially involve four phases of evaluation: against DTV signals and against wireless microphones, both in the lab and in the field.
Shure had proposed live testing at an NFL football game, designed in close cooperation with the Society of Broadcast Engineers (SBE) and its Gameday Frequency Coordinators. However, the FCC was unable to work within the timeframe of the NFL season, largely because the commission is still receiving prototype devices for evaluation. “While Shure understands that the scheduling did not line up, it is unfortunate that the NFL field tests could not be accommodated as proposed, because we believe that this environment is the best representation of real world pro audio RF operation in the television spectrum,” Brunner said.
As the opposing forces in the white spaces debate jockey for the technological high ground, it is becoming clearer that all parties involved have learned the importance of mutual cooperation and accommodation in achieving their goals.
For more information, visit www.fcc.gov.
