A blind receiver for digital communications in shallow water

In spring 1999, a sea trial in the coastal region of the Dutch North Sea has been conducted in the scope of the EU-MAST III project ROBLINKS to obtain underwater acoustic data for digital communication in shallow water environments. In this paper, we propose a blind receiver architecture and present results of its application to some specific communication signals transmitted during the experiment. The receiver structure used in the analysis is based on a self-trained adaptive equaliser, designed to jointly process the signals from the vertical receiver hydrophone array and to perform the tasks of timing and carrier recovery. The experimental results demonstrate that self-recovering equalisation for coherent communication in shallow water is possible over a range of several kilometres with data rates exceeding 3 kbit/s.