Blind and efficient modulation format identification based on fourth-power characteristic value

In this paper, a novel blind modulation format identification method is proposed based on fourth-power characteristic value, the effectiveness of this method is demonstrated and discussed in a 20GBaud long-haul coherent transmission system. It has been proved the usage of FFT peak value and variance is able to achieve accurate estimation among DP-QPSK/16QAM/32QAM/64QAM.