Electronic Design
White Spaces Test Taps Unused TV Channels For Wireless Opportunities

White Spaces Test Taps Unused TV Channels For Wireless Opportunities

The long-discussed idea of using white spaces—the unused TV broadcast channels made available by the analog-to-digital TV transition—for other applications is turning into reality. Last year, a test in rural Claudeville, Va., proved that white spaces could be used successfully. Now a second test performed by TV Band Service (TVBS) LLC, in partnership with Spectrum Bridge Inc., makes the case again. The coalition announced that the city of Wilmington and county of New Hanover, N.C., launched the nation’s first “Smart City” wireless network trial using the TV white spaces spectrum.

The Wilmington/New Hanover county area was chosen for this trial network because it was the first major U.S. TV market, as selected by the Federal Communications Commission, to convert from analog to digital TV broadcasting. In what local officials describe as a “model for public-private partnerships,” the network will help government leaders identify how TV white spaces can expand existing as well as deliver new cost-effective, environmentally friendly services.

TV white spaces involve frequencies that vary from location to location, depending upon which channels are occupied. These bands lie in the VHF and UHF bands from 50 to 698 MHz. Wireless data networks are an excellent fit here, because their lower frequency translates into longer-distance signals and more reliable communications. The FCC ruled that these frequencies can be used on an unlicensed basis, much like Wi-Fi. Currently, the FCC is at work finalizing other rules and regulations for white spaces.

The figure shows how much white space spectrum is available in the U.S. Such a vast amount of white spaces projects enormous potential for delivering cost-effective connectivity among a wide range of consumer, business, and government applications. Some of the initial applications deployed in Wilmington using TV white spaces frequencies include:

Department of Transportation traffic cameras: Provides real-time traffic monitoring for the Department of Transportation to reduce congestion, fuel consumption, and travel time; supports local law enforcement; and assists with hurricane and disaster evacuations

Public safety and Wi-Fi access at community parks: Delivers real-time video monitoring to improve overall security and gives local law enforcement a virtual presence in the parks; boosts productivity among county employees and offers citizens the opportunity to stay connected via laptops, smart phones, and netbooks

Water and wetlands monitoring: Enables remote monitoring and management of wetland areas, eliminating the costs associated with physically driving or boating to the monitoring stations to collect data required by the Environmental Protection Agency (EPA)

Other Smart City applications in the planning stage include:

Water pump station monitoring and control: Reduces energy consumption and costs, increases equipment life, and allows for faster identification and mitigation of spills

Medical telemetry: Enables remote monitoring and reporting of biometric measurements for “at risk” populations

Expanded broadband access for schools: Increases student, teacher, and administration access to Internet-based educational resources

The initial tests used modified frequency-shift-keying (FSK) IP radios designed for industrial telemetry and control. Data speeds of up to 2 Mbits/s were achieved on channels 25 (536 to 542 MHz) and 32 (578 to 584 MHz). Though each channel is 6 MHz wide, only about 2 MHz is used in these applications. The FCC restricts the wattage rating to 4-W effective isotropic radiated power (EIRP).

To ensure that a white spaces network doesn’t interfere with licensed television broadcasts and other protected TV band users, the system is controlled by Spectrum Bridge’s intelligent TV white spaces database. This database dynamically assigns non-interfering frequencies to white spaces devices. It also adapts in real time to new TV broadcasts, as well as other protected TV band users operating in the area.

“This network is further evidence that TV white spaces can be used to deliver innovative services without impacting protected users operating in nearby TV channels,” says Peter Stanforth, CTO and co-founder of Spectrum Bridge. “The valuable data and know-how gained from real-world network deployments greatly increases our understanding of how TV white spaces and database-driven spectrum access can cost-effectively address the increasing demand for wireless bandwidth.”

To find TV white spaces availability for any U.S. location, use the free search tool at Spectrum Bridge’s ShowMyWhiteSpace.com Web site, or download the company’s free Show My White Space iPhone application from the Apple App Store. The figure shows that at any given time, huge chunks of unused spectrum are available across the U.S.

Spectrum Bridge Inc.

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