Iterative equalization for underwater acoustic channels using bit interleaved coded modulation and decision feedback equalization

An iterative receiver scheme combining decision feedback equalizer (DFE) and bit interleaved coded modulation (BCIM-ID), suitable for transmission over frequency selective channels with large delay spread is proposed, where adaptive equalization and channel decoding are jointly optimized. Extensive simulation results presented for a realistic underwater time varying multipath channel exhibiting multipath delay spread of the order of 10 ms for data rates of 8 kbps, demonstrate that the proposed receiver not only reduces intersymbol interference and error propagation in the DFE, but also provides better bit error rate (BER) performance than the system employing turbo codes.