A reconfigurable wavelet packet filter bank transceiver for spectral analysis and dynamic spectrum access

A reconfigurable wavelet packet transceiver for spectral analysis and dynamic spectrum access is proposed. The transceiver consists of a Wavelet Packet Spectral Estimator (WPSE) and a Wavelet Packet Multi-carrier Modulator (WPM) both of which are implemented using filter banks. The WPSE estimates the radio environment and identifies spectrum holes and occupied bands. This information is then used to shape the time-frequency characteristics of the WPM transmission waveform in a way that the occupied bands are evaded. This is done by vacating those sub-carriers which lie in and around the occupied bands. The WPSE uses the same filter bank structure as used for WPM data modulation and hence doesn´t add to the implementation costs. Through computer simulations the operation of the proposed system is demonstrated. The performances are also compared with two other candidate systems based on Fast Fourier Transform (FFT) and Orthogonal Frequency Division Multiplexing (OFDM). The studies show that WPSE/WPM, in relation to FFT/OFDM, offers better bit-error-rate (BER) performance and bandwidth efficiency. This is facilitated by the excellent time-frequency localization of wavelet filters which results in better estimation of spectrum and spectral confinement of transmission waveform.