Recognition and Parameter Estimation of MPSK Signals Based on Instantaneous Phase Difference

There many researches about modulation mode classification of the MPSK signals, but these studies pay few attentions to some especial MPSK signals such as OQPSK or π/4QPSK. However, the signals are very important in the digital communications. The method of classification of the QPSK, OQPSK, π/4QPSK and 8PSK has discussed in this paper, because these MPSK signals have similar constellations or spectrum. The method of the classification and parameter estimation based on the statistical and spectral characters of the instantaneous phase difference (IPD) is proposed. The simulation results of the digital signals indicate that this method is availability when the SNR is higher than 5dB.