QUITE A FEW FIRMS have emerged with solutions in the recently liberated television white-space band. At the heart of Adaptrum's system, for instance, is cognitive-radio technology that uses any available spectrum below 1 GHz. In late June, this firm demonstrated its radio system at the Cambridge TV Whitespace Trial launch event in Cambridge, UK. To do so, Adaptrum had to establish a TV whitespace broadband connection under highly challenging propagation conditions. The firm succeeded, showing that its solution could deliver consistent highthroughput data connectivity even when other wireless technologies, such as WiFi, fell short.

In the demonstration, the Adaptrum white-space system provided broadband Internet-protocol (IP) connectivity. It allowed a clientside Microsoft XBOX video game console to stream live high-definition (HD) videos from the Internet (see photo). In addition, a live XBOX/Kinect video chat was established between two XBOX/ Kinect units using the same TV white-space connection. These applications were demonstrated in a radio-propagation environment that suffered more than 120 dB link loss through buildings, foliage, walls, furniture, people, and more. It also had to endure severe multipath effects.

Because the intent of the demonstration was to show the complete TV white-space system, the Adaptrum radio system also interacted with the Microsoft UK TV white-space database for the updated channel list at Cambridge. According to Adaptrum, unlicensed technology may close the gap between the demand for wireless bandwidth and the actual supply. WiFi has been offloading much of today's wireless data traffic. Going forward, however, Adaptrum predicts that TV white-space technology will provide wireless bandwidth where WiFi cannot. With its flexible architecture, the Adaptrum solution can support different types of services and applications while meeting the stringent interference requirements established by the Federal Communications Commission (FCC).