Patent Document ID: 20150180689
Application ID: 14136239
Patent Flag: 0

Claim One:
1. A method for spectrum sensing for cognitive radio, the method comprising: detecting edges of frequency bands, detecting energies in frequency bands, and to deciding whether frequency bands area available to cognitive radio users; receiving a time-domain signal by a cognitive radio user; estimating a power spectral density of the time-domain signal; calculating wavelet transform coefficients at one or more scale factors by convolving the power spectral density with a first derivative of a wavelet smoothing function; obtaining a positive signal by taking the absolute value of all wavelet transform coefficients, and if more than one wavelet scale factor is used, combining wavelet transform coefficients of different scales; comparing the positive signal to a noise threshold and where the positive signal is less than the noise threshold setting the positive signal to zero; detecting one or more frequency-band edges of the power spectral density by solving for peak frequencies, wherein the peak frequencies are frequencies of the local maxima of the positive signal; defining a plurality of frequency bands as all frequencies between nearest neighbor pairs of frequency-band edges; determining a received energy value for a first frequency band of a plurality of frequency bands comparing the received energy value to an energy threshold; and signaling frequency band availability based on the comparison between the received energy value and the energy threshold.