Abstract:

In order to compare the advantage and shortcoming  of two Doppler estimation algorithms for OFDM（Orthogonal Frequency-Division Multiplexing） in underwater acoustic communication,a lacustrine experiment was carried out.The replica correlation time delay difference estimation algorithm is simple and easy to achieve,and the null subcarriers algorithm is complex and accurate.The same experimental dates are estimated and compensated based on the two algorithms,and error bit rates are compared.The results show that the two methods have mainly uniform error bit rates in slowvarying UWA(Underwater Acousitic) channels,but the null subcarriers algorithm is more stable in fast time-varying channels.

Key words: underwater acoustic communication, orthogonal frequency-division multiplexing (OFDM), Doppler estimation, null subcarriers, linear frequency modulation(LFM)