Wireless microphone maker Shure says FCC field trials of devices from Motorola, Philips, Adaptrum and InfoComm International prove unlicensed use of white spaces will create interference at venues like NFL, NBA and MLB games and Broadway plays that depend on wireless microphones. One FCC test of white spaces devices Aug. 9 during the Buffalo Bills-Washington Redskins game at Washington, D.C.'s FedEx Field interfered with game coverage. Google, the Wireless Innovation Alliance and other proponents of using the interference buffer zones between digital television channels to deliver wireless broadband dismiss concerns.
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
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
"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
Which is exactly what the Wireless Innovation Alliance did after the FedEx
"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
that the testing conducted prior to the FedEx Field tests already
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
and set-top boxes that can utilize the white spaces.
All of the devices would have to be certified by the FCC.