Blind modulation recognition of PSK signals based on constellation reconstruction

A system based on constellation reconstruction for blind Modulation recognition of MPSK/MDPSK signals in non-cooperative communication applications is proposed. The system requires no prior information about the signal, and parameters needed in the procedure of constellation reconstruction such as carrier frequency, symbol rate and timing information, are estimated from received data samples. And the method of phase difference is used to eliminate the constellation diagram pervasion aroused by carrier frequency offset. Subordinate function is also been proposed and defined in this paper, the function which calculates its value by utilizing clustering number obtained from clustering of the constellation, so different MPSK/MDPSK signals can be classified by different values of the function. In AWGN channel, simulation proved that when SNR>lldB, the recognition ratio are above 90% for all kinds of signals, and for BPSK, 4PSK signals the ratio can achieve 100% when SNR>6dB, it shows the system is effective.