Efficient Delay Wave Suppression Using Spatio-Temporal Equalization with Unequally Spaced Array for Underwater Acoustic Communications

We propose a spatio-temporal equalizer with an unequally spaced array that improves delayed wave suppression in the spatial domain to overcome double-selective fading in underwater acoustic communications. Delayed waves from every direction cannot be efficiently suppressed by equally spaced arrays with a limited number of elements because of the trade-off between spatial resolution and spatial aliasing. Arranging elements unequally reduces spatial aliasing effects without sacrificing spatial resolution, thereby eliminating the trade-off. Our simulations demonstrated our method’s effectiveness in suppressing delayed waves from every direction.