Cognitive Radio System using IEEE 802.11a over UHF TVWS

The FCC is contemplating opening up UHF TVWS for cognitive radios - there is a demand for a Cognitive System that can operate on available channels. In this paper we present the system architecture of a prototype Cognitive Radio System using IEEE 802.11a MAC over UHF TVWS. The cognitive radio network consists of a cognitive access point (that performs in-band and out of band sensing) and Cognitive Mobile Stations. The paper presents the various components of the system and their interactions. The Cognitive Engine we present is designed to be agnostic of the underlying MAC and PHY. To this end, we define an abstraction layer to interface with the MAC. A Geo-location based approach for detecting incumbents like DTV, assisted by spectrum sensing, is proposed. We also propose a Cognitive Engine Protocol for channel resource control between the Cognitive Access Point and Cognitive Stations. Finally, results of the prototyped system are presented.