Parallel resampling receiver for underwater acoustic communication with non-uniform Doppler shifts

This paper presents a resampling method for underwater acoustic communication with non-uniform Doppler shifts. The current trend of Doppler compensation is two-step processing that consists of resampling and residual carrier frequency offset (CFO) compensation. In conventional approaches, a resampling ratio is assumed to be roughly constant and estimated on average in the measured Doppler shifts. However, the appropriate resampling ratio is not always consistent with the average. It can be confirmed by the simple OFDM demodulation test with various Doppler shift patterns. We propose a parallel resampling receiver using multiple resampling ratios by taking account into Doppler shift dispersion. The effectiveness of the parallel resampling has been verified by our sea trial.