Identification of the Wavelet Packet Modulation Signals Based on Fractional Fourier Transform

According to the modulation principles of orthogonal frequency division multiplexing (OFDM) and wavelet packet modulation (WPM), this paper discusses the modulation identification for WPM signals from the OFDM signals based on fractional Fourier transform (FRFT). The FRFT clustering area of the signals is used as the classification feature parameter. Simulations are carried out in additive white Gaussian noise (AWGN), Rayleigh fading and frequency selective fading channels. It is shown that the new algorithm works well for all the considered channels, indicating potential applications in the recognition of WPM signals in blind channels.