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在水声通信中,发射与接收端相对运动引起的多普勒频移会严重恶化OFDM系统传输效果。因此多普勒频移估计是水声通信的关键技术之一。本文采用的最大Dopp ler频移估计算法,是利用信道功率谱的分布对接收的导频信号进行频域差分检测来进行估计。这种方法复杂度低,精度较高,无需获得正确的信道时域冲击响应信息,也无需再对信号进行自相关运算,而且特别适用于低信噪比的水声通信系统。
In underwater acoustic communication, the Doppler shift caused by the relative motion between the transmitting and the receiving end can seriously deteriorate the transmission performance of the OFDM system. Therefore Doppler frequency shift estimation is one of the key technologies of underwater acoustic communication. In this paper, the maximum Doppler frequency shift estimation algorithm is used to estimate the frequency domain difference of the received pilot signal by using the distribution of channel power spectrum. This method has low complexity and high precision, and does not need to obtain the correct channel time-domain impulse response information or the signal autocorrelation. It is especially suitable for underwater acoustic communication systems with low signal-to-noise ratio.