The invention provides a spectrum sensing method based on
polarizability, which is suitable for
cognitive radio networks. The method comprises the following steps of: setting a
system detection threshold, continuously sampling space electromagnetic signals, estimating a
covariance matrix of the received signals, obtaining the
polarizability of the received signals based on a characteristic value of the
covariance matrix, thereby, judging existence of electromagnetic signals according to the
polarizability difference between signals and noises. The method can realize application of polarization information of electromagnetic signals of authorized users, and effectively solves the problem of indeterminacy of
noise in practice; the polarizability is obtained based on a sampling
covariance matrix of the received signals, and detection can be performed without using the prior knowledge of signals, channels or noises; the method is suitable for
small sample detection, and can reduce computational complexity, improve detection speed of the
system to the electromagnetic signals and reduce detection time of the
system to the electromagnetic signals. Thus, the method can meet the requirement on real-time detection, and is beneficial for efficient usage of limited
radio spectrum resource.