Joint iterative equalization and decoding for underwater acoustic coherent communication systems

Serially concatenated trellis coded modulation(SCTCM) technology is adopted to improve the bandwidth efficiency of the underwater acoustic channel.In order to overcome multi-path fading and eliminate inter-symbol interference(ISI),the turbo theory is applied to form the joint iterative multi-channel adaptive decision feedback equalizer(MC-ADFE) and decoder of SCTCM.In the joint iterative equalization and decoding(JIED) algorithm,the MC-ADFE and decoder of SCTCM exchange soft information in an iterative manner,which can enhance the equalizer performance using the significant decoding gain.Simulation results show that the proposed system scheme can improve the performance of the equalizer and lead to a considerable coding gain.So,the performance of the underwater acoustic communication system has been improved greatly.