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Complementary Set of Sequences (CSS) are being widely used in communications due to the ideal correlation properties and the availability of efficient correlators that significantly reduce the number of computations in the detection process. In this paper, the performance of the acoustic signals encoded by multilevel CSS in an underwater horizontal link is analysed. For that, a channel propagation...
In underwater acoustic communications, spread-spectrum signals can be used to obtain frame synchronization in a data packet. However, the underwater channel is highly challenging due to phenomena such as multipath, Doppler effect and noise, so this detection can be difficult under certain conditions. With regards to noise, several sources can be present in the ocean at a certain time, providing a...
Ocean noise is a complex phenomenon in underwater environments. Different processes such as shipping traffic, wind, rain or animals contribute with a different signature to the background noise, which can worsen underwater systems performance. However, in the simulation of underwater systems the common approach is to consider an additive white Gaussian noise with a certain given value. Usually, the...
The underwater channel is a highly variable medium due to the influence of several effects on the acoustic signal, and the physical variability of the environment. This behavior makes the underwater channel a very difficult one to model, and also a complex environment to work with. In acoustic-based positioning or sonar systems, where it is important to know accurately the time-of-flights of the signals,...
Underwater acoustic channel modeling keeps being an active field of research, despite the fact that the physical effects are known since decades ago. The great variability that is found in this kind of channel makes modeling a difficult task, being highly dependent on a particular environment. For high frequencies, ray tracing is a simple and reliable solution, giving a good approximation and a lot...
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