Single-carrier iterative frequency-domain equalization with soft decision feedback in shallow underwater acoustic communication

This paper investigates a single-carrier iterative frequency-domain equalization (SC-IFDE) scheme for high-rate underwater acoustic (UA) communication systems. This scheme is based on the minimum mean-squared error (MMSE) criterion, and soft decision feedback is applied to improve the reliability of the equalizer decision. The proposed algorithm is applied to the data received during the UA communication experiment conducted in December 2012 in the Indian Ocean off Rottnest Island, Western Australia. It is demonstrated that using one transmitting transducer and one receiving hydrophone, the proposed SC-IFDE algorithm achieves an average of 3% uncoded bit-error-rate (BER) with quaternary phase shift keying (QPSK) modulated signals over a range of 1 km.