水声通信Doppler扩展估计的实验研究

Experimental study of Doppler spreading estimation in underwater acoustic communication

发射机和接收机之间的相对运动引起Doppler扩展,即时间选择性衰落,它导致发射信号频率扩展。Doppler扩展是动态通信时导致误码率上升的主要原因之一,所以通信接收机首先需要估计Doppler扩展,然后才能补偿Doppler扩展,从而够降低动态情况下的误码率。单频信号是频率敏感信号,根据相对发射机的频率偏移量可以估计Doppler扩展。由于声传播速率相对较低,Doppler扩展导致接收信号相对发射信号产生时间上的伸缩变化,这样也可以采用测量伸缩量的办法估计Doppler扩展。通过水声通信湖上试验,验证了这两种方法的可行性,为未来的水声通信研究提供借鉴和参考。

Relative motion between the transmitter and the receiver results in Doppler spreading,time selective dispersion,which results in transmitted signal frequency spread.In moving communication,Doppler spreading is one of main causes to deteriorate communication performances,the receiver needs to estimate it firstly and then compensate it,so that the receiver is able to reduce bit error rate further.Tone signal is frequency sensitive signal,and Doppler estimation is done by frequency offset from the transmitted signal to receiver.Due to relative low speed of acoustic transmission in water,Doppler spreading results in time extension and compression of receiving signal relative to transmitted signal,so it can be estimated by measuring time extension and compression.By analyzing the lake trial data,two methods are tested,and a reference for underwater communication research in the future is provided.