Spectrum sensing method based on symmetrical peaks of cyclic autocorrelation function of modulated signal

摘要

#$%^&*AU2020204624A120200813.pdf#####ABSTRACT The present invention relates to a spectrum sensing method based on symmetrical peaks of a cyclic autocorrelation function of modulated signals. A cognitive user calculates a cyclic autocorrelation function of the signal received, and constructs a two-dimensional signal detection domain accordingly. Finally, symmetrical peak points are searched for in the two-dimensional signal detection domain to determine whether a primary user signal is present. If there are symmetrical peak points in the two-dimensional signal detection domain, it is determined that the primary user signal is present; otherwise, it is determined that the primary user signal is absent. To ensure a false alarm probability of spectrum sensing required, a significance level factor of the symmetrical peak points is introduced in the searching for the symmetrical peak points in the invention. In the method of the present invention, the symmetry of peaks of the cyclic autocorrelation function of modulated signals is used to detect whether the primary user signal is present. It does not require any priori information of the primary user signal and the channel, and eliminate the effect of channel noise fluctuations on spectrum sensing performance. Thereby, it resolves the spectrum sensing challenge in a low signal-to-noise ratio and channel noise fluctuations.2/2 r(t) = s(t) + n(t) Set significance level factorfp according to false alarm probability Pfa Calculate cyclic autocorrelation function of signal received Ra(-) Construct detection domain of signal received Ra(T) Calculate mean l and variance a12 of Ra(T) for r and mean p2 and variances a22 of Ra(T) for a, respectively Search for pair of symmetric peaks R1 and R2 in Ra(T) Rj|,p1+pe1~ or |Rj|,P2+peo2 Primary user signal is present Primary user signal is absent FIG. 2