Blind Constellation Recognition Algorithm for OFDM Systems Through Unknow Multipath Channel

This paper proposes a novel blind constellation recognition algorithm for Orthogonal Frequency Division Multiplexing(OFDM)system.This scheme utilizes the statistic property of OFDM system instead of pilot frequency and training sequence.Combined with blind channel estimation algorithm and blind equalization algorithm,the scheme chooses robust decision parameters to blindly discriminate the type of constellation for each subchannel in OFDM system under unknown multipath channel.Computer simulation shows that this method can completely discriminate MPSK-OFDM and high order MQAM-OFDM in frequency-selective channels under the condition that the E_b/N_0 is higher than 16 dB and more than 1000 symbols are used.Furthermore,computer simulation shows that this method works well for MPSK-OFDM in frequency-selective channels under the condition that the E_b/N_0 is higher than 2 dB.