Real-time high data rate acoustic link based on spatio-temporal blind equalization: the TRIDENT acoustic system

There is no doubt about the growing interest for the underwater acoustic communications. Among all existing applications, the objective of the Groupe d´Etudes Sous-Marines de l´Atlantique (GESMA) is to develop a sufficiently robust high data rate acoustic link, named TRIDENT. For that purpose, different kinds of information (texts, images...) could be periodically transmitted through the acoustic channel. A realtime receiver, based on the spatio-temporal blind adaptive decision feedback equalizer, developed and patented by ENST Bretagne [J. Labet et al., 1995], was designed to cope with all perturbations induced by such harsh channels. Some sea trials have been carried out in June 2002. The first results are clearly convincing since most of the 48 sequences of 5 minutes are successfully detected by the DSP-based real-time receiver. This acoustic system allows transmission at data rates ranging from 8 to 25 kbps in horizontal configuration.