The accurate timing algorithm of pseudo random sequence in vertical underwater acoustic communication
To solve the problem of timing error caused by time-varying Doppler in vertical underwater acoustic communication,an iterative timing estimation and compensation algorithm based on pseudo-random sequence is studied in this paper.The method uses pseudo-random sequence as synchronization signal,and estimates time-varying Doppler in three steps:a low complexity ambiguity function is used to roughly compensate the average Doppler in the received signal;the accurate estimation and compensation of residual time-varying Doppler are realized by iterative interpolation method;the phase information of correlation function based on the channel is used to correct the deflection phase of the equalized signal.Then,to further realize the effective demodulation of high-order sea trial data,multi-channel weighted combination based on mean square error of pseudo-random sequence is adopted to obtain spatial diversity gain.The simulation and sea trial data processing results show that the proposed method has good time-varying Doppler estimation and compensation performance,and the 1024QAM data in 30 channels are combined and processed.At the communication distance of 500 m,the BER is 0.04,and the channel capacity reaches up to 7.6 bits/symbol.Compared with the traditional data frame structure,the linear frequency modulation signal is unnecessary,so the effective data transmission rate can be improved.
Underwater acoustic communicationPseudo random sequenceDoppler estimationMulti channel merge
万方数据
维普
