Broadcasters worried about the effects of unlicensed
broadband data devices operating between licensed TV channels—the so-called
“white spaces”—need to know that these bits of spectrum are now being used.
One of the first operations to actually go live is called AIR. U, named after
the Advanced Internet Regions consortium. On July 9, it fired up a system at
West Virginia University in Morgantown, W.Va.
Calling itself “the first university in the U.S. to use vacant broadcast TV
channels to provide the campus and nearby areas with wireless broadband
Internet services,” AIR.U provides free
public Wi-Fi access.
“AIR. U demonstrates the real potential
of innovation and new technologies to
deliver broadband coverage and capacity
to rural areas and small towns to drive
economic development and quality of life,
and to compete with the rest of the world
in the knowledge economy,” West Virginia University Chief Information Officer
John Campbell said in a press release.
For the time being, AIR. U is being used
to provide the final link to locations that
it would otherwise be impractical for data
access. One example is West Virginia University’s
Public Rapid Transit, a 73-car tram
system that transports more than 15,000
With the AIR. U system, a data link on an
unused TV channel feeds a Wi-Fi router at
each tram platform, which is then used to
get Wi-Fi access on the moving trams.
The university just fired the system up
and there’s been minimal use with the
students out for summer break, but Campbell
expects usage to dramatically increase
when students return to campus.
He expects that the university and its
partners will look at the system’s use and
decide how to expand the system after
gathering enough data.
Campbell added that the university
doesn’t have a defined end date for the
project, and are currently meeting to discuss
additional potential projects. “Those
projects will primarily focus on increasing
wireless access for faculty, staff and students,
as well as a potential project with
the city,” he said.
The event did not go unnoticed by others
who have an interest in using white
“The innovative WVU network demonstrates
why it is critical that the FCC allows
companies and communities to use vacant
TV channel spectrum on an unlicensed basis,”
said Michael Calabrese, director of the
wireless future project at the Washington-based
New America Foundation, which is
affiliated with AIR. U.
AIR. U boasts a list of backers that include
Google and Microsoft, as well as
regional organizations such as the Appalachian
Regional Commission, the New
England Board of Higher Education and
the Corporation for Education Network
Initiatives in California. In announcements
regarding the system at West Virginia University,
the team members refer to the
technology as “Super WiFi.”
|Kiely Cronin of Carlson Wireless sets up one of the company’s
outdoor client units.
WRAL, the Raleigh, N.C. CBS affiliate,
has teamed with Carlson Wireless Technologies
in an FCC-sanctioned test of
unlicensed white space technology this
summer. Carlson Wireless is providing its
RuralConnect base stations, and the project
has been granted a Special Temporary
Authority by the FCC.
For its part, Carlson Wireless is convinced
that unlicensed white
space devices can peacefully
coexist with broadcasters.
“The regulations behind
TVWS are designed to prevent
interference,” said Kiely
Cronin, TV white space
product development manager
for Carlson Wireless
Technologies in Arcata, Calif.
“TVWS radios, for instance,
must operate through a
database manager to acquire
a list of available channels. In addition to that, the
FCC has mandated strict
emission requirements so
that radios using designated
channels don’t interfere outside
of that space.”
Cronin stated emphatically
that interference with
licensed broadcasters is
simply not going to happen.
For the past half decade, the
NAB has been working with
the FCC to create the rules
under which white space
devices will work, and is not
opposed to the rollout of white space data
services and tests.
Specialists in DTV broadcasting are not
so sure about the lack of interference, however.
“The available amount of white space
spectrum will be significantly reduced
if many DTV channels are taken away
by the FCC for broadband wireless use,
and many DTV stations remain on the air
crammed into the remaining spectrum,”
said Gary Sgrignoli, DTV transmission
consultant and partner at Meintel, Sgrignoli,
& Wallace in Mount Prospect, Ill.
“Without even considering white space
device interference, there is a real concern
that after a spectrum repack the remaining
DTV signals may interfere with
one another if special care in RF channel
allocations is not taken, as described so
often by Charlie Rhodes in his TV Technology
Cindy Hutter Cavell, senior engineer at
the consulting engineering firm of Manassas,
Va.-based Cavell, Mertz & Associates,
“With the impending TV band repack, it
remains to be seen as to how much white
space will be available for any sort of device,”
ROOM FOR DISAGREEMENT
When it comes to the possibility of interference
with licensed DTV broadcasts,
the experts find some room for disagreement.
Sgrignoli said that DTV-into-DTV interference from fixed transmitter sites with
known frequencies and power levels is difficult
enough by itself, but the problem is
significantly increased when dealing with
mobile devices like white space products
that can be randomly placed in proximity
to DTV receive antennas.
“Since the white space devices are
frequency adaptive and low-power, it is
unlikely that they will have any material
impact on over-the-air reception,” Hutter
Cavell said. “It is possible that these devices
will have some effect on uncoordinated
equipment such as wireless microphones
and IFBs in broadcast venues, as well as in
stadiums, auditoriums, churches and other
entities that use wireless mics.”
Still, if interference does happen, finding
the culprit won’t be easy.
“Determination of DTV interference
from white space devices is certainly a
concern for broadcasters,” Sgrignoli said.
“This concern stems from the difficulty
in measuring white space signals that are
not constantly transmitting and that might
be changing frequency and/or transmit
power sporadically as needed. A typical
spectrum analyzer will not do the job,
and therefore specialized test equipment
would be needed during a site evaluation
by an engineer.”
Hutter Cavell pointed out that there is
a published list of approved white space
products, which can help stations understand
what sort of devices might be the
culprits. There is also a list of approved coordinators
for such devices, although there
are only two at the moment—a third is in
final stages of approval. These frequency
coordinators should be helpful in solving
PROMOTING HIGH-SPEED INTERNET
The demand for wireless Internet connectivity
is insatiable, however, and pressure
is coming from the highest levels of
government to bring such spectrum online.
Commenting on the WVU network,
West Virginia Senator Jay Rockefeller, chairman
of the Senate Committee on Commerce,
Science and Transportation, said, “I
have made promoting high-speed Internet
deployment throughout West Virginia, and
around the nation, a priority. That is why
I am excited by [the July] announcement
of the new innovative wireless broadband
initiative on West Virginia University’s campus.
Wireless broadband is an important
part of bringing the economic, educational,
and social benefits of broadband to all
Kiely Cronin of Carlson Wireless said
that his company sees wireless broadband
services in white space channels as a “disruptive
technology,” one that can break
through the technical barriers imposed
by the current network of cable and fiber
web connections. Riding the wave of that
disruption is what Carlson Wireless hopes
One thing in favor of unlicensed broadband
data on white space frequencies
is that it is likely to shy away from urban
areas that have dense lineups of DTV stations.
These areas are already well served
with Internet service providers and they
generally don’t need additional competition.
In rural areas, there may be only a
handful of TV broadcasters.
Cronin said that a Carlson Wireless base
station can work with a client from as far
away as 10 miles, although connecting
within a one-mile radius is more typical.
“Right now, wireless broadband delivered
using white space devices is primarily
a rural solution, as rural areas have the best
channel availability,” Cronin said. “However,
as lower-powered mobile devices come
to market, we should see increased urban