Measurements performed at several locations clearly show that frequency spectrum is under‐utilized. Cognitive radio (CR) is a strong candidate to ensure better spectrum utilization by providing access in an opportunistic manner, i.e., when the spectrum is temporary or spatially unutilized (a.k.a. white‐space). The key enabling technology for realizing better frequency spectrum utilization in CR system is spectrum sensing. In particular, spectrum sensing in television (TV) bands is of great interest due to the potential availability of spectrum as a result of the planned migration of analog TV broadcasting to digital TV broadcasting. In this paper, we present the TV white‐space prototype that we developed to detect vacant spectrum in TV bands. The prototype is implemented on a real‐time platform and tested in practical environments. Results show that our prototype is able to detect vacant channels up to sensitivities from −116 to −120 dBm under realistic conditions. This confirmation will give the much needed confidence in the capability of CR systems to detect the operation of primary users and protect their use of spectrum. Copyright © 2008 John Wiley & Sons, Ltd.

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