Article

Performance of the Direct-Sequence Spread Spectrum Underwater Acoustic Communication System with Differential Detection in Strong Multipath Propagation Conditions (en)

* Presenting author
Day / Time: 08.03.2023, 15:00-15:20
Room: Saal X 3-4
Typ: Vortrag (strukturierte Sitzung)
Abstract: Direct-Sequence Spread Spectrum (DSSS) is one of the modulation and coding techniques used in Underwater Acoustic Communication (UAC) systems for reliable data transmision even at low signal levels. However, in a shallow water channel, there is a strong multipath propagation which causes a phase fluctuation of the received signal, affecting the performance of the spread-spectrum system. This paper presents the results of simulation and experimental communication tests of a DSSS-based UAC system using different spreading sequences and occupying different bandwidths from 1 kHz to 5 kHz around a carrier frequency equal to 30 kHz. The detection at the receiver side was perfomed using a differential method for DSSS signal detection. It is based on the calculation of the correlation coefficient of adjacent segments of signal at the output of filter matched to the spreading sequence used in the transmitter. The reliability of this method has been compared to classical methods of DSSS signal detection, which consist in detecting the information directly from the signal at the output of the matched filter. Simulation and measurement tests of underwater acoustic communications have shown, that the use of differential detection method significantly improves reliability of the DSSS system in strong multipath propagation conditions.
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