Improvement of blind multichannel receivers for underwater acoustic communications by delay-based equalizer initialization

Bandwidth efficient underwater acoustic communication is achieved by employing phase coherent receivers that require an equalization step to counter signal distortions caused by multipath spreading. The equalizer can be adapted by utilizing so-called blind methods that do not rely on any cooperation of a transmitter, but evaluate properties of a signal itself. Although such algorithms allow for a data-rate efficient use of the channel, they can suffer from slow convergence which is influenced by the initial choice of the equalizer solution. In this paper a new initialization approach is proposed that improves the convergence behavior of a blind multichannel feedforward equalizers by exploiting relative delays between the signals that are received by different sensors. The improvement is shown by simulation-based analysis and is experimentally verified by processing data from the ROBLINKS sea trial.