VHF UHF WiFi Solutions for Super WiFi

What are the White Spaces?

White spaces are vacant frequencies located between broadcast TV channels in the
VHF/UHF range, located between 54 MHz and 806 MHz. The VHF (very high
frequency) range includes channels 2 through 13, located between 30 MHz and 300 MHz
on the electromagnetic spectrum, while the UHF (ultra high frequency) range includes
channels 14 through 51, located at 300 MHz and up.

Broadcast TV now makes more efficient use of this spectrum ever since the 2009 DTV
transition from analog to digital transmission because digital TV can be compressed into
fewer channels.

Only a small portion of this spectrum is in use, even in urban areas. Throughout the
United States, the amounts and exact frequency of vacant TV spectrum vary from
location to location. Generally, the more rural the area, the more available white space,
since fewer TV stations are located in regions of lower population density.
Each available TV channel provides 6 MHz of spectrum capacity for use by wireless
devices—good news for unlicensed wireless devices like Wi-Fi, Bluetooth and cordless
phones, which have been crowding the airwaves at the 2.4 GHz and 5 GHz frequencies.
Different frequencies have specific characteristics, some longer, some shorter, some
spreading, some bending and some requiring a line of sight to travel on. For example,
when using 5 GHz at distances greater than a half mile, line of sight becomes critical,
thus devices using that frequency require repeaters and large antennas to get a strong
signal.

VHF/UHF frequencies, on the other hand, spread widely and can penetrate obstacles,
which means that using them for communications requires little infrastructure—more
good news for residents of rural parts of the country who may not want or be able to build
high communications towers in their communities.

Background
In November 2008, the FCC gave notice it was proposing rules for unlicensed use of TV
white space, but had not yet settled on how its use would be managed. The following
year, Congress mandated that all TV broadcasting would be digital, and by June 2009,
analog TV ceased to broadcast.

For a year, the FCC deliberated amid controversy about how to manage the TV white
spaces so that devices did not cause interference to one another. Television broadcasters,
as well as operators of wireless microphone and other low-power devices already using
the white-space frequencies, were concerned about interference. Manufacturers waited to
find out if devices would need to include expensive geolocation or spectrum-sensing
technology to prevent interference.

Finally, in September 2010, the FCC announced the white spaces would be available,
license-free, managed by a database. According to the FCC ruling, the database will track
which frequencies are occupied by TV broadcasters in all parts of the country and which ones are available in each region for use by wireless devices. The FCC set aside two vacant UHF channels for wireless microphones, etc. Users of the white spaces will be
required to register in the database.

Florida-based entrepreneurial company Spectrum Bridge is among the companies that
have applied for the contract to manage the national white-space database. During 2009-
2010, while technology companies waited for the FCC to decide how the white space
frequencies would be managed, Spectrum Bridge applied for experimental licenses and
tested white-space technology in real world situations.

White-Space Technology Passes Rigorous Field Testing
Three strenuous field tests were conducted that demonstrated
the effectiveness of whitespace technology in rural, urban and industrial settings. To date, each of these networks remains a valuable resource to its surrounding community.
High-Speed Internet Access for a Remotely Located Community
Claudville, Virginia, tucked into the thick forests of the Blue Ridge Mountains, has 916
residents whose only internet access before the test was through slow dial-up or
expensive satellite. White-space technology provided high speed internet access for
schools, businesses and residences. In order to reach all the Claudville sites, white-space
signal travels 1.5 miles from router, which shows it can operate with less than a tenth of
the nodes required by Wi-Fi.

City-Wide Networking with No Reports of Interference
The city of Wilmington, North Carolina, population 75,838, is using TV white spaces for
a municipal wireless network and to expand broadband at local schools. The “Smart
City” network includes public safety communications, municipal water monitoring,
traffic cameras and healthcare telemetry.

Rural Electric Grid Gains Robust, Long-Ranging Control Links without Line of Sight
Plumas-Sierra Rural Electric Cooperative, whose subscribers are scattered throughout the
mountains and canyons of rural Northern California, uses TV white spaces for its
wireless “Smart Grid” network. The electric co-op is using this network for remote
management of the supply-and-demand for electricity, remote control for substations, and
SCADA (supervisory control and data acquisition). It also provided broadband internet
access to its subscribers. In this test, some of the links exceed five miles, demonstrating
the long range of white-space frequencies.

Superior Qualities for Broadband
The availability and unique qualities of the white-space frequencies promise to make
broadband faster, cheaper and more widely available, especially in rural areas, where TV
white space is more abundant. The signal is robust, is unaffected by weather, works well
in rugged terrain and requires little infrastructure to deploy.

More Bandwidth in Rural Areas
White-space frequencies have the capacity to carry wireless data at speeds far greater
than Wi-Fi, earning white-space technologies the nicknames “Super Wi-Fi” and “Wi-Fi
on Steroids,” due to the sheer availability of bandwidth in the VHF/UHF spectrum.
Actual bandwidth depends on how much white space is available in a given area and how
many devices make use of that bandwidth at a given time. Rural areas have an estimated
20 vacant TV channels, while suburban areas have around 10. This means that the
bandwidth capacities of the white-space frequencies are higher in rural areas than in
urban ones, simply because there are more available channels and fewer subscribers per
square mile.

Each available TV channel consists of 6 MHz of bandwidth. One channel, sharing the
upstream and downstream traffic with Time Division Duplexing (TDD), has the potential
to carry 8 to 16 Mbps. This speed will depend on the FCC finalizing its rules for whitespace usage, particularly its out-of-band emissions rules.

Superior Range and Coverage
In hilly regions, the area white-space frequencies can cover is typically two to six times
that of Wi-Fi. This is due to the particular characteristics of the low radio frequencies,
which carry farther and penetrate better. Ground waves cling to the curvature of the earth,
spreading over greater distances and requiring less power to do so. For broadband use,
this means that fewer base units are required to cover greater areas and that access points
can serve larger areas.

Greater Signal Penetration
White-space frequencies penetrate obstacles, a characteristic that makes them particularly
promising for affordable rural broadband because little new infrastructure or land
alteration is required for deployment. Up to now, rugged terrain has posed
the greatest challenge to using radio technology for rural broadband because microwave frequencies, like the 2.4 GHz used for Wi-Fi, require a line of sight, meaning the components of radio equipment must be visible to each other.
In mountainous or thickly forested country, this line-of-sight requirement means towers must be built to hold transmitters, receivers, repeaters and antennas. In rural areas with only a few customers per square mile, Internet service providers (ISPs) cannot justify the expense of building towers. Further, many rural residents are not eager to see such towers rise up in the midst of their natural environment, nor do they want to clear the forests in order to get broadband into their neighborhoods.

VHF/UHF frequencies, however, can travel from miles away, penetrating foliage, stone,
brick and even metal to reach all the corners inside a building—the qualities that made
them work well as TV signals. This means ISPs will not need to build new infrastructure
in order to deploy broadband in rural communities.

Our equipment solutions for this is found in the VHF-UHF category.

VHF UHF SUPER WIFI

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