Characterization of Underwater Acoustic Channel Using SAVEX15 MIMO Signals

Abstract

The underwater acoustic channel is characterized as a time-varying and delay-spreading channel. Therefore, in the viewpoint of underwater acoustic communications, coherence time and coherence bandwidth (or RMS delay spread) are key parameters for estimating the performance of communication systems. To estimate the parameters multi-tone and BPSK-modulated MLS signals were transmitted during SAVEX151. A vertical source array of eight spherical transducers (SRA) and two vertical arrays of 16 hydrophones (VLAs) were used for transmitting and receiving the signals. Whereas the two VLAs were moored over the seafloor, the SRA was operated either in the tethered mode or in the autonomous mode. Three sets of multi-tone data were transmitted simultaneously using three transducers (#1, #5, and #8) and they are switched within the transducers using a repeating pattern of three different cycles in a round-robin. Their frequency components were between 10