Iterative block DFE techniques based on LDPC for SC-FDE underwater acoustic communications

An iterative block decision-feedback equalizer based on LDPC (LDPC-IBDEF) for SCFDE underwater acoustic (UWA) communication system is proposed. The new equalizer employs IBDFE together with iterative LDPC decoding technique, leading to a double-layer structure which can solve the frequency selective fading problem in UWA channel. In the outer-layer, IBDFE iteratively exchanges information with the LDPC channel decoder to improve its performance. Sea tests carried out in Xiamen Harbor show that the average BER performance of the new scheme for SCFDE system is in the order of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-3</sup> , when the data rate is 2kbps and the distance is 10km.