Hardware implementation of FFT-based spectrum sensing techniques for cognitive radio

This paper presents the hardware implementation of FFT-based spectral correlation and pilot sensing spectrum sensing techniques defined in IEEE 802.22 standard. Both techniques estimate the spectrum of the incoming signal, where the spectral correlation technique calculates the ratio between two specific frequency components of the signal and evaluates if there is signal present in the channel; and the pilot sensing technique calculates the greatest value of the spectrum and compares that value for two consecutive spectrums to determine if there is signal present in the channel. Both spectrum sensing techniques are implemented on an FPGA and their performances were tested using an ATSC signal captured with a spectrum analyzer. Our implementation of the spectral correlation technique can detect an ATSC signal with a signal to noise ratio greater than -24.3 dB, and the pilot sensing technique can detect the ATSC signal with a signal to noise ratio greater than -33 dB.