Experimental Investigation of Signal Sensing with Overlapped FFT Based Energy Detection

Overlapped FFT based energy detection has been proposed as a signal detection scheme in dynamic spectrum access. The overlapped FFT scheme increases the number of FFT frames to reduce the variance of squared noise and improve the detection probability. This paper evaluates the performance of the energy detection with overlapped FFT through experiments. In the experiments, different from the assumption in computer simulation of previous researches, a fixed distortion component caused by a direct current offset is observed. It is shown that the overlapped FFT scheme also works effectively under the existence of the fixed distortion. Numerical results obtained through the experiments show that the overlapped FFT scheme improves the detection probability by up to 0.15 with the noise and the fixed distortion component. The variance of the squared noise also reduces with the overlapped FFT scheme as it is expected in theoretical analysis when the fixed distortion is negligible.