Characterization of long-range time-varying underwater acoustic communication channels

We present communication channel characterizations performed on in-situ measurements from the Baltic and North Sea. The communication channels were probed using pseudorandom binary sequences (PRBS), obtaining time-variant channel impulse responses through wideband matched filtering. Characteristics central to communications were obtained. Included are: scattering functions, coherence-times and coherence bandwidths. The validity of the quasi wide sense stationary uncorrelated scattering (quasi-WSSUS) assumption was also investigated for the measured channels. Measurements were acquired in the joint European project “UUV Covert Acoustic Communications.” The project aims to design an acoustic communication system between an unmanned underwater vehicle (UUV) and a support mother ship. The first sea trials of the project focused on the acquisition of noise and long-range, low-frequency communication channel data for the explicit purpose of building an acoustic channel simulator.