Improved Windowed Cross Wigner-Ville Distribution for PSK Class Signals

Abstract

Instantaneous information bearing phase is an important parameters in the analysis of a digitally phase modulated signal. Cross time-frequency distributions (XTFD) have been proposed recently to represent the class of Phase Shift Keying (PSK) signals. However, due to the presence of duplicated terms, the estimation of the instantaneous bearing phase is inaccurate. A fixed lag window width can be used as a kernel but it is insufficient to completely remove the duplicated terms. Here, a new improved windowed cross Wigner-Ville distribution (XWVD) is proposed as a method to obtain a better cross time-frequency representation (XTFR) for binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) signals. By adaptively adjusting the lag window width, the duplicated terms are removed and an accurate representation of the cross TFR are obtained at low SNR conditions, as low as 3dB.