Shure is sure. After the Federal Communications Commission tested white spaces devices at the Buffalo-Washington preseason game Aug. 9 at FedEx Field, the nation's dominant maker of wireless microphones pronounced the field trials a bust.
White spaces are interference buffer zones between digital television channels that Google, Microsoft, Motorola and other tech powers think are ideal for delivering wireless broadband. The National Association of Broadcasters claims the use of the spectrum will interfere with its channels and sports organizations like the NFL and MLB maintain that the unlicensed use of white spaces will cause interference with the use of wireless microphones.
"The FCC's tests of prototype white space devices at FedEx Field prior to Saturday's game ... conclusively show that spectrum-sensing white space devices will cause harmful interference to wireless microphones during live events," Mark Brunner, Shure's senior director for Public and Industry Relations, said in a statement. "Simply stated, the prototype devices were unable to consistently identify operating wireless microphones or distinguish occupied from unoccupied TV channels."
The spectrum between the channels will become available after Feb. 17 when broadcasters make the switch to digital broadcasting. The FCC began testing white spaces devices with mixed results in January using a prototype device supplied by Microsoft. In July, the agency moved the tests outdoors using devices from Motorola, Philips, Adaptrum and InfoComm International. Motorola has already called the outdoor tests a success.
Motorola's device combined sensing technology with geolocation to find existing channels and route signals around the channel. Motorola, however, did not participate in the testing of white spaces and wireless microphones.
"Given the poor performance of these sensing devices, there is no reason to believe that the other proposed protections, such as beacons, will be any more capable of providing reliable and robust interference protection to wireless microphone transmissions," Brunner said. "These tests reveal fundamental deficiencies of sensing devices-issues that cannot be pushed off with a promise to resolve these problems at some later time during certification testing."
Which is exactly what the Wireless Innovation Alliance did after the FedEx Field tests.
"Just as the bench testing has shown time and time again, the science behind spectrum sensing is sound. The current field tests, including Saturday's test at FedEx Field, have done nothing to contradict the previous results," said Jake Ward, a spokesperson for the Alliance. "The FCC has the information it needs to move forward with their final report and the development of rules of the road for white space technologies."
Google also dismissed the tests before they even began. Richard Whitt, Google's Washington telecom and media counsel, wrote in an Aug. 8 policy blog that the testing conducted prior to the FedEx Field tests already validates Google's March white spaces filing with the FCC.(PDF) In that filing, Google said the use of geolocation databases, beacons and safe harbors would protect digital television channels and wireless microphones.
"In particular, stand-alone use of a geolocation database with a look-up function would offer complete protection to digital TV and wireless microphone signals at major venues," Whitt wrote Aug. 8. "Importantly, under our approach no WSD [white spaces device] would transmit, even if it failed to detect any signals at all, without first receiving affirmative permission from a geolocation database look-up."
He added, "With or without spectrum sensing, it's abundantly clear that unlicensed devices can coexist successfully with licensed services, with no reasonable fear of harmful interference."
When the FCC concludes the outdoors testing, the agency will then prepare a report and make overall recommendations on the use of white spaces devices. If the FCC supports the use of white spaces, device makers like Motorola could start manufacturing technology for laptops, smart phones, PDAs and set-top boxes that can utilize the white spaces. All of the devices would have to be certified by the FCC.