Optimizing of iterative turbo equalizer for underwater acoustic channel

Underwater acoustic communications have multipath errors because of reflection by sea-level and sea-bottom. The multipath of underwater channel causes signal distortion and error floor. In order to improve the performance, it is necessary to employ an iterative coding scheme. Among the iterative coding schemes, turbo codes and LDPC codes are dominant channel coding schemes in recent. This paper concluded that turbo coding scheme is optimal one for underwater communications system in aspect to performance, coded word length, and equalization applications. Also, we confirmed that iterative equalization using soft information from the turbo decoder further enhances the receiver performance in the environment of oceanic experimentation with distance of 5Km and data rate of 1Kbps.