Experimental study of spectrum sensing based on energy detection and network cooperation

Spectrum sensing has been identified as a key enabling functionality to ensure that cognitive radios would not interfere with primary users, by reliably detecting primary user signals. Recent research studied spectrum sensing using energy detection and network cooperation via modeling and simulations. However, there is a lack of experimental study that shows the feasibility and practical performance limits of this approach under real noise and interference sources in wireless channels. In this work, we implemented energy detector on a wireless testbed and measured the required sensing time needed to achieve the desired probability of detection and false alarm for modulated and sinewave-pilot signals in low SNR regime. We measured the minimum detectable signal levels set by the receiver noise uncertainties. Our experimental study also measured the sensing improvements achieved via network cooperation, identified the robust threshold rule for hard decision combining and quantified the effects of spatial separation between radios in indoor environments.