The invention discloses a
frequency spectrum perceiving method based on the
estimation of a
signal arrival direction, which comprises the steps: in a
cognitive radio system to which
smart antenna technology is applied, the direction and the angle of
signal transmission are used as a
frequency spectrum opportunity, and a master user
signal is subjected to two-step
perception: firstly, the master user signal is detected by using a method based on a
generalized likelihood ratio test, namely that the ratio of the
maximum eigenvalue to the sum of the eigenvalues of a sample
covariance matrix is used as test statistics; the test statistics are compared with a
decision threshold which is set according to a given
false alarm probability so as to decide whether the master user signal exists or not; if a master user does not exist, then the channel can be used, and if the master user exists, then a classical MUSIC (
Multiple Signal Classification)
algorithm is further used to estimate the arrival direction of the master user signal. A
cognitive user can select other directions for communication, which do not cause disturbance to the master user, and the
frequency spectrum perceiving method can effectively perceive time, frequency and the frequency spectrum vacancy of a space domain, perceive the frequency spectrum vacancy of an angle domain, and increase the frequency spectrum opportunity.