Broadband Doppler compensation: Principles and new results

The underwater acoustic channel is particularly challenging for high-data-rate digital communications due to its large delay spread and rapid time variation. The transmitted signal bandwidth is also a substantial fraction of its center frequency, such that platform mobility gives rise to Doppler effects manifested as time-varying temporal scaling of the waveform. This paper develops a novel Doppler compensation method that recursively tracks the optimal (in an approximate MMSE sense) resampling of the received waveform. Performance on real ocean acoustic data verify an order of magnitude improvement over existing gross-Doppler plus phase-locked-loop methods.