Fractional-rate radiometer for spectrum sensing based on I/Q branch separation

Radiometer has a peculiar place among spectrum sensing techniques available in the literature, because it has a simplistic design and is known to be the optimal detector in the absence of a priori knowledge about the signal to be detected. In this study, it is shown that simplicity in the traditional radiometer design could further be improved while its performance is maintained. The proposed method exploits the inherent orthogonality between the I/Q branches and reduces the total number of addition and multiplication operations at baseband. Results are validated by the experimental data collected under different digital modulation scenarios. Relevant discussions and future directions are outlined as well.