A high-frequency warm shallow water acoustic communications channel model and measurements

Abstract

Underwater acoustic communication is a core enabling technology with applications in ocean monitoring using remote sensors and autonomous underwater vehicles. One of the more challenging underwater acoustic communication channels is the medium-range very shallow warm-water channel, common in tropical coastal regions. This channel exhibits two key features-extensive time-varying multipath and high levels of non-Gaussian ambient noise due to snapping shrimp-both of which limit the performance of traditional communication techniques. A good understanding of the communications channel is key to the design of communication systems. It aids in the development of signal processing techniques as well as in the testing of the techniques via simulation. In this article, a physics-based channel model for the very shallow warm-water acoustic channel at high frequencies is developed, which are of interest to medium-range communication system developers. The model is based on ray acoustics and includes time-varying statistical effects as well as non-Gaussian ambient noise statistics observed during channel studies. The model is calibrated and its accuracy validated using measurements made at sea.

Underwater Acoustic Communications: Design Considerations on the Physical Layer

“…Suffice it to say that unlike in a radio channel, where a number of models for both the probability distribution (e.g., Rayleigh fading) and the power spectral density of the fading process (e.g., the Jakes' model) are well accepted and even standardized, there is no consensus on statistical characterization of acoustic communication channels. Experimental results suggest that some channels may just as well be characterized as deterministic, while others seem to exhibit Rice or Rayleigh fading [12]. Channel coherence times below 100 ms have been observed, but not often.…”

Comprehensive Study of Acoustic Channel Models for Underwater Wireless Communication Networks

“…Moreover, the model does not include acoustic propagation physics, e.g., spreading and absorption.. An underwater acoustic channel based on Rice fading model is introduced in [8] where there can be several propagation paths named Eigen paths and the Poisson distribution is used to represent the number of Eigen paths reaching a receiver. Themodelsproposed in [9] are simple deep water acoustic models. These models include acoustic propagation physics such as spreading and absorption and captures transmission losses due to sea surface and sea bottom.…”

DTN Routing Protocol Utilizing Underwater Channel Properties in Underwater Wireless Sensor Networks

“…6. Observed fading of arrival at 1020m [10] 용함으로써 줄일 수 있다 [9] . 이때 대역폭 B(l)은 수식 (5)와 같이 나타낼 수 있다 [8] .…”