The heavy use of wireless communications bands has made the notion of Cognitive Radio (CR) attractive. Cognitive radio can be achieved by sensing and detecting available frequency bands before initiating communication. RF bandpass Sigma-Delta modulators have been suggested as potential candidates for highly digitized receivers dedicated to cognitive radio applications.
Nevertheless, the measured Dynamic Range (DR) of state-of-the-art RF bandpass Sigma-Delta ADCs is not sufficient to satisfy the requirements of wireless communication standards.
Furthermore, in order to sweep the spectrum and detect different wireless communication standards, it is necessary to have a bandpass Sigma-Delta ADCs with a tunable center frequency.
In this work we propose an Cognitive Radio RF front-end receiver based on a wide-band LNA and a tunable bandpass Sigma-Delta ADC. The proposed RF front-end can operate from 1.5-to-3GHz and can satisfy the specifications of several wireless communication standards in this band.
The main contribution of this work can be summarized in the following: