1: The iteration parameter 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. |