Patent ID: 8718960

Claim:
A method comprising: selecting a first frequency band; verifying, by a computer, whether or not the selected first frequency band is signal-free; determining the first frequency band as a target measurement frequency when the verifying verifies that the selected first frequency band is signal-free; and measuring a background radio noise in the determined target measurement frequency, wherein the verifying includes: acquiring time domain data in association with the first frequency band, configuring an autocorrelation matrix using the acquired time domain data, calculating a singular value σ k through singular value decomposition (SVD) using the autocorrelation matrix, computing a parameter v(k) using the singular value σ k , and verifying whether or not the first frequency band is signal-free based on the parameter v(k), and the parameter v(k) is computed by an Equation: v ⁡ ( k ) =  A ( k )  F  A  F = [ ∑ i = 1 k ⁢ σ i 2 ∑ i = 1 h ⁢ σ i 2 ] 1 2 where A is a data matrix consisting of time-domain data, ∥A∥ F is a Frobenius-norm of matrix A, ∥A (k) ∥ F is a Frobenius-norm of matrix A(k) that is approximated using a singular value from a first to a kth, k is an index of the singular value and h is a maximum value of rank.