Contribution
Underwater Acoustic Communications with Objects Near the Bottom of the Water Body
* Presenting author
Abstract:
Underwater Acoustic Communications is used, among others, in infrastructure monitoring systems at the bottom of a body of water. The transmitter or receiver of such a system is located close to the bottom or lies on the bottom. A phenomenon that has a strong impact on signal transmission conditions in such a scenario is multipath propagation. In the impulse responses of the communication channel, very numerous and difficult to distinguish propagation paths are visible. As a result of multipath propagation, the transmitted signal undergoes time dispersion which results in inter-symbol interference observed on the receiving side. In such conditions it may be impossible to obtain reliable data transmission without using a matched filtering algorithm in the receiver. The paper presents the results of data transmission tests carried out in the lake using three kinds of signals that require the matched filters in the receiver, namely: Direct-Sequence Spread Spectrum (DSSS) waveforms, Linear Frequency Modulated (LFM) waveforms, and Multi-LFM waveforms.