Mobile underwater acoustic communication technology has been widely used in marine meas-urement and offshore engineering.The irregular relative motion between transmitter and receiver leads to time-varying Doppler shifts,which can cause severe inter-carrier interference(ICI)and thus affect the performance of orthogonal chirp division multiplexing(OCDM)communication.Conventional techniques such as resampling and residual carrier frequency offset can only handle constant Doppler frequency shift.This paper proposes a new method for handling time-varying Doppler shifts by adding multiplex resampling to OCDM communica-tions.This method extends the resampling range based on the measured Doppler standard deviation and thus reduces the bit error rate(BER)in mobile underwater acoustic communications.Meanwhile,compared to using a fixed number of branches,using a variable number of branches in multiplex resampling lowers computational complexity and saves roughly 30%of the computational cost.It details the implementation and parameter selec-tion of the Doppler-resistant OCDM in mobile underwater acoustic communication,and compare the perform-ance of multiplex resampling and single resampling by simulation and actual measurement in Qiandao Lake.The proposed method's viability and exellent anti-time-varying Doppler shift performance,are confirmed by the BER and frame error ratio(FER)results.
关键词
移动水声通信/正交Chirp复用/时变多普勒频移/抗多普勒
Key words
mobile underwater acoustic communication(UWA)/orthogonal chirp division multiplexing(OCDM)/time-varying Doppler shift/anti-Doppler
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