The unoccupied radio spectrum between broadcast TV channels may soon become a source of low-cost, ubiquitous broadband connectivity. Earlier this month, the U.S. Federal Communications Commission began Phase II testing of prototype “white space devices” (WSDs), to determine whether they can operate without interfering with the wireless devices commonly used in homes, offices, and public locations.
WSD technology represents an interesting alternative to the as-yet unrealized combination of WiFi and WiMax for low-cost, ubiquitous broadband access.
A key advantage of the TV white space frequencies, relative to WiFI and WiMAX, is that “the characteristics that make them good for TV — their ability to cover broad areas and penetrate walls and trees — also make them advantageous for sending and receiving broadband data,” according to a Microsoft-sponsored advertisement.
Microsoft is a member of the Wireless Innovation Alliance, which is urging the FCC to approve the use of TV white space for both fixed and mobile consumer applications, such as laptops, TVs, set-top boxes, PDAs, MP3 players, printers, and digital cameras.
A little WSD history
In the fall of 2006, the FCC approved the use of TV white space for fixed broadband deployments. At that time, however, the FCC declined to approve the use of TV white space for low-power fixed and mobile personal devices pending an investigation of the potential for “harmful interference” from WSDs.
Following initial evaluations last fall, Phase II WSD testing by the FCC began on Jan. 18, 2008. The purpose of this test program is to “[assess] the interference potential of such devices and establishing appropriate requirements,” the Commission says. In the current round of tests, prototype WSDs submitted by Adaptrum, Microsoft, Motorola, and Philips, will be field-tested to evaluate their performance under real world conditions. This phase of the tests is expected to last between two and three months.
After WSD prototype tests have been completed to the FCC’s satisfaction, the Commission will set about defining a set of WSD operating rules. Once that happens, consumer electronics companies will begin moving forward in developing WSDs and bringing them to market.
Possible WSD applications
As part of the migration of U.S. TV stations to digital transmission technology, between 12 and 40 unused channels will become available in each U.S. metropolitan area in February of 2009.
The New America Foundation, a “nonprofit, post-partisan, think tank,” believes WSD technology utilizing these unused channels has the potential to “stimulate new innovations in consumer products, services, and applications.”
The Foundation lists the following key applications for WSDs:
- Rural broadband deployments — TV white space offers greater range, including the ability to pass through buildings, weather, and foliage, at lower power levels
- Public safety communications — in emergencies, the WSDs can provide auxiliary services to augment existing public safety communications
- Education and enterprise video conferencing — WSDs can increase the reliability and decrease the cost of video conferencing on college and commercial campuses
- A variety of personal consumer applications — WSDs could provide new services and applications to consumers by taking advantage of the improved signal reliability, capacity, and range of the TV broadcast spectrum
- Mesh and ad-hoc networks — WSDs can be used to implement and enhance mesh networking, resulting in numerous applications and benefits
- Security applications — WSDs can be used for video surveillance and monitoring, childcare monitoring in the home or in childcare facilities, and other security applications
- Municipal broadband access — WSDs could increase the quality of service and decrease the deployment costs for municipal wireless broadband networks
- Enhanced local coverage and communications — WSDs could enable mobile video and audio services and citizen journalism
- Enterprise networking — WSD-based wireless broadband services could enable small businesses to improve their productivity
For more information about white space technology, visit the website of the Wireless Innovation Alliance, which includes Microsoft, Google, HP, and Dell among its membership.