Carlson White Spaces White Paper

8/3/2019 Carlson White Spaces White Paper

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Super Wi-Fi

WHITE PAPER

Using TV White Spaces for Rural Broadband

MAR 2011

Karol Andersson, Carlson Wireless Technologies

[email protected]


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2WHITE PAPER: Super Wi-Fi: Using TV White Spaces for Rural Broadband

Rural Americawhere natural beauty abounds as does a strong connection to the landand the community. Those who choose to stay in rural areas often do so at the sacrice

of the greater economic opportunities that lie closer to cities.

But as the information age moves forward, rural communities need not be left behind. High-speed internet access can provide people who live in the most remote parts of the country

with the advantages of economic opportunities, distance learning and telemedicine.

Up until now, however, broadband has simply not been available in many parts of ruralAmericafor a number of reasons. Fiber-optic cable and satellite access are oftenprohibitively expensive, while microwave radio technology requires expensive towers tobe constructed so that pieces of equipment have a line of sight in order to communicate

with one another.

Finally, thanks to a recent decision by the Federal Communications Commission (FCC),there is another option: using vacant TV frequencies to provide broadband connectivity.

For rural Americans, this means affordable broadband is coming soon to their communities

with no need to build unsightly towers, cut down trees or alter the natural landscape.Super Wi-Fi is what the FCC is calling the expanse of broadcast frequencies thathave just become available for wireless communications. Faster, more robust and more

readily available than traditional Wi-Fi, the new spectrum is located in the vast amountof unused TV channels, also known as white spaces.

The FCC ruled September 2010 that the white-spacefrequencies are now available for free, unlicensed public

usea decision that has major implications for ruralbroadband. Getting broadband connectivity to the most

rural and remote parts of the country is a national priority,and it is in those rural areas where white-space frequenciesare most plentiful.

Furthermore, the distinct characteristics of white-spacefrequencies make them ideally suited for rural broadband.

For example, the signal penetrates obstacles making itefcient even in mountainous or thickly forested terrain.

The signal also propagates, in other words, it spreadswidely and stays close to the ground without losing

strength. This means not only that it can cover a widerrange with less infrastructure, but also that it has the

bandwidth capacity to meet todays Internet demands.

What are the White Spaces?

White spaces are vacant frequencies located between

broadcast TV channels in the VHF/UHF range, locatedbetween 54 MHz and 806 MHz. The VHF (very high

frequency) range includes channels 2 through 13, locatedbetween 30 MHz and 300 MHz on the electromagnetic

spectrum, while the UHF (ultra high frequency) rangeincludes channels 14 through 51, located at 300 MHz andup.

Ever since the 2009 DTV transition from analog to digitaltransmission, broadcast TV now makes more efcient use

of this spectrum because digital TV can be compressedinto fewer channels.

Only a small portion of this spectrum is in use, even inurban areas. Throughout the United States, the amounts

and exact frequency of vacant TV spectrum vary fromlocation to location. Generally, the more rural the area, themore available white space, since fewer TV stations are

located in regions of lower population density.

Each available TV channel provides 6 MHz of spectrum

capacitygood news for unlicensed wireless deviceslike Wi-Fi, Bluetooth and cordless phones, which have

been crowding the airwaves at the 2.4 GHz and 5 GHzfrequencies.

Different frequencies have specic characteristics, somelonger, 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 frequencyrequire repeaters and large antennas to get a strong signal.

VHF/UHF frequencies, on the other hand, spread widelyand can penetrate obstacles, which means that using them

for communications requires little infrastructuremoregood news for residents of rural parts of the country who


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WHITE PAPER: Super Wi-Fi: Using TV White Spaces for Rural Broadband

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 hadnot yet settled on how use of the spectrum would be

managed. Soon afterwards, Congress mandated that all TVbroadcasting would be digital, and by June 2009, analog

TV ceased to broadcast.

For a year, the FCC deliberated amid controversy abouthow to manage the TV white spaces so that devices did not

cause interference to one another. Television broadcasterswere concerned about interference, as were operators of

wireless microphones and other low-power devices thatalready used the white-space frequencies. Manufacturers

waited to nd out if devices would need to includeexpensive 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 willtrack which frequencies are occupied by TV broadcasters

in all parts of the country and which ones are available ineach region for use by wireless devices. The FCC set aside

two vacant UHF channels for use by wireless microphones,etc. Users of the remaining white spaces will be required to

register in a national database.

Florida-based entrepreneurial company Spectrum Bridge

is among the nine companies the FCC appointed January2011 to manage the national database of TV channels.

During 2009-2010, while technology companies waited forthe FCC to decide how TV white space would be managed,

Spectrum Bridge applied for experimental licenses andtested white-space technology in real world situations (Seesidebar.).

The other eight companies the FCC appointed January2011 to manage the spectrum geo-location database are

Comsearch, Frequency Finder, Google, KB Enterprises,LS Telcom, Key Bridge Global, Neustar, Telcordia

Technologies and W5db. The FCC Ofce of Engineeringand Technology (OET) will oversee these companies,

which must attend a series of mandatory workshops andconduct real-world tests such as the ones Spectrum Bridgehas already conducted.

Under this model, TV white-space equipment is expected tobe certiable for commercial sale by May 2011. Meanwhile,

Carlson Wireless TV white-space radio, RuralConnect IP,is only available under FCC-granted experimental license,

with experimental projects presently under construction inNorthern California, Oklahoma, Michigan and Connecticut.

Superior Qualities for Broadband

The availability and unique qualities of the white-space

White-Space Technology PassesRigorous Field Tests

Three strenuous eld tests were conductedthat demonstrated the effectiveness of white-space technology in rural, urban and industrialsettings. To date, each of these networks

remains a valuable resource to its surroundingcommunity.

High-Speed Internet in a Remotely

Located Community

Claudville, Virginia, tucked into the thick for-ests of the Blue Ridge Mountains, has 916residents whose only internet access beforethe test was through slow dial-up or expensivesatellite. Schools, businesses and residencesare using TV white-space for broadband. In

order to reach all the Claudville sites, the sig-nal travels 1.5 miles from router, which showsit can operate with less than a tenth of thenodes required by Wi-Fi.

Urban Public Safety Networking with No

Interference

The city of Wilmington, North Carolina, popu-lation 75,838, is using TV white spaces fora municipal wireless network and to expandbroadband at local schools. The Smart Citynetwork includes public safety communica-tions, municipal water monitoring, trafc cam-eras and healthcare telemetry.

Rural Electric Grid Gains Control Links

without Line of Sight

Plumas-Sierra Rural Electric Cooperative,whose subscribers are scattered throughoutthe mountains and canyons of rural NorthernCalifornia, uses TV white spaces for its wire-

less Smart Grid network. The electric co-opis using this network for remote managementof the supply-and-demand for electricity,remote control of substations, and SCADA(supervisory control and data acquisition). Theco-op also uses TV white space to providebroadband to its subscribers. Some links ex-ceed ve miles, demonstrating the long rangeof white-space frequencies.


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WHITE PAPER: Super Wi-Fi: Using TV White Spaces for Rural Broadband

frequencies promise to make broadband faster, less

expensive and more widely available, especially in ruralareas, where TV white space is more abundant. The signalis robust, is unaffected by weather, works well in rugged

terrain and requires little infrastructure to deploy.

More Bandwidth in Rural AreasDue to the sheer availability of bandwidth in the VHF/UHF

spectrum, white-space frequencies have the capacity

to carry wireless data at speeds far greater than Wi-Fi,earning white-space technology the nicknames Super Wi-

Fi and Wi-Fi on Steroids.

Actual bandwidth depends on how much white space isavailable in a given area and how many devices makeuse of that bandwidth at a given time. Rural areas have

an estimated 20 vacant TV channels, while suburbanareas have around 10. This means that the bandwidth

capacities of the white-space frequencies are higher in ruralareas 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 trafcwith Time Division Duplexing (TDD), has the potential tocarry 8 to 16 Mbps. This speed will depend on the FCC

nalizing its rules for white-space usage, particularly its out-of-band emissions rules.

Superior Range and Coverage

In hilly regions, the area white-space frequencies can coveris typically two to six times that of Wi-Fi. This is due to theparticular characteristics of the low radio frequencies, which

carry farther and penetrate better. Ground waves cling tothe 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 greaterareas and that access points can serve larger areas.

2010 Carlson Wireless Technologies, Inc

RuralConnect IP from Carlson Wireless Technologies

Carlson Wireless Technologies is proud to be the rst to offer broadband equipment that uses the

TV white-space frequencies for a proven last-mile and middle-mile solution: RuralConnect IP.

For more information about RuralConnect IP, please visit

http://www.carlsonwireless.com/products/ruralconnect_ip.php

Greater Signal Penetration

White-space frequencies penetrate obstacles, acharacteristic that makes them particularly promising foraffordable 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 becausemicrowave 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 large towers must be built to hold

transmitters, receivers, repeaters and antennas. In ruralareas with only a few customers per square mile, Internet

service providers (ISPs) cannot justify the expense ofbuilding large towers. Further, many rural residents arenot eager to see such towers rise up in the midst of their

natural environment, nor do they want to clear the forests inorder to get broadband into their neighborhoods.

VHF/UHF frequencies, however, can travel from milesaway, penetrating foliage, stone, brick and even metal to

reach all the corners inside a buildingthe qualities thatmade them work well as TV signals. This means ISPs

will not need to build new infrastructure in order to deploybroadband in rural communities.

The Next Step: Broadband in Every Corner of the

Country

The U.S. National Broadband Plan indicates thatbroadband is a modern necessity, not a luxury. Broadband

is necessary to conduct business, research, education andmany other everyday activities in todays world. For rural

communities, broadband is a way for residents to access

economic opportunity and higher education without leavingthe community. And now, with a bounty of newly availablespectrum, broadband is coming to the most rural regions ofthe country.

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Carlson White Spaces White Paper