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What is your idea for a white space radio? Many companies are considering this new wireless option since the FCC opened new frequencies after the switchover to digital TV in the U.S. White spaces are open TV frequencies that can now be used in unlicensed wireless applications if they do not cause interference. This approach to spectrum utilization should turn up some interesting new products.

White space frequencies are those below 800 MHz and the lower VHF frequencies. Many are in the 500-700 MHz range. Signals in these frequencies tend to travel farther than higher microwave frequencies, and tests show they also have better success in penetrating walls, trees, and other obstructions, which translates to more robust wireless links and improved reliability in wireless devices.

Since the available white space channels vary in different areas, a major design issue is how to make a radio that will identify the unused channels and find a suitable vacant one. This means the radio needs to have a broad range and know which signals not to trample on. Cambridge Consultants, an IP company in the U.K., has a solution called InCognito. This novel, low-cost spectral sensing cognitive radio technology platform allows any radio product to transmit without interference on white space frequencies.

Cambridge Consultants’ design uses a standard data radio that includes a separate sensing receiver. The receiver’s output is digitized and sent to a processor running several algorithms that identify protected signals, primarily digital TV and wireless microphones. The algorithms then seek out suitable unoccupied frequencies for new wireless products to use.

Luke D’Arcy of Cambridge Consultants sees several interesting new applications. A longer-range Wi-Fi-like service is one possibility. Another is a broadband wireless radio that will provide high-speed Internet service to rural areas that are currently unable to access the Web. White space channels are also ideal for distributing video around the home. A central transmitter tied to a set top box or other source could wirelessly send video to TV receivers. D’Arcy believes that we will quickly see a wave of innovation in wireless products and services around 700 MHz with Cambridge Consultants’ new spectral sensing technique. Obviously, there are many possibilities. What is yours?

Cambridge Consultants has a complete reference design for InCognito radios at cambridgeconsultants.com. Additional information on white space radio is also available at the Cognitive Networking Alliance (CogNEA) at cognea.org.