Soft-Input Soft-Output Bidirectional DFE for underwater acoustic communication

Underwater acoustic channel is one of the most challenging channel for data transmission due to its long multipath delay and Doppler expansion. In this paper, Soft-Input Soft-Output Bidirectional DFE is extended to multilevel modulations and applied in underwater acoustic communication. The performances of both exact and Low-complexity implemented Soft Bidirectional DFE are evaluated at low SNR by simulation and pool experiment. Experimental results show that data rate of 12 kbit/s could be readily achieved without error.