1. A method for classifying a received signal, the method comprising: determining a covariance matrix of signal values of the received signal; determining an eigenvalue matrix of the covariance matrix, the eigenvalue matrix comprising the eigenvalues of the covariance matrix; determine a first function from at least one eigenvalue of the eigenvalues of the covariance matrix; determine a second function from at least one eigenvalue of the eigenvalues of the covariance matrix, wherein the second function is different from the first function; and classifying the received signal into a signal comprising data or into a noise signal dependent from a comparison between a value of the first function and a value of the second function.