1: The iteration parameter 𝑗 is initialized to zero. The input signal is converted into a matrix of two rows by repeating
 the signal.
2: The low pass and high pass filter toeplitz matrices of the corresponding iteration are calculated.
3: The Multiwavelet packet coefficients are obtained.
4: Check whether the required iteration level is achieved. If yes go to next step. Otherwise increase the iteration parameter and
 repeat step 2 and 3.
5: If the required iteration level is reached the wavelet packet coefficients are saved and energy of the subbands are calculated.
6: The power spectral density is obtained and is compared with the predefined threshold.
7: Preliminary decision on vacant spectrum is taken based on step 6.
Algorithm 1