Decision fractional fast Fourier transform Doppler compensation in underwater acoustic orthogonal frequency division multiplexing.

A method of compensating for Doppler distortions of underwater acoustic channels for orthogonal frequency division multiplexing (OFDM) signals is proposed. This method is based on symbol rebuilding. OFDM symbol rebuilding is performed after fractional fast Fourier transform (F-FFT) processing. A stochastic gradient-type adaptive algorithm is designed to learn the combiner weights for detection. Synthetic data and experimental data from a recent mobile acoustic communication experiment are used to demonstrate the performance of the proposed method, which represents a significant improvement over the F-FFT detection technique.