A high frequency acoustic experiment was conducted in the northern portion of the Gulf of Mexico in August 2016 to examine the operating range, data rates, and performance of acoustic communication systems at the carrier frequency of 85 kHz. The received signal-to-noise ratios, channel coherence, and impulse responses were reported between two 85 kHz transducers and a five-element hydrophone array over multiple ranges up to 1500 m. Channel estimation based decision feedback equalizers (DFEs) were applied to process the communication measurements. A data rate of 27.2 kb/s was achieved for four tested ranges with a uniform set of receiver parameters.
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http://dx.doi.org/10.1121/1.5006141 | DOI Listing |
J Acoust Soc Am
January 2025
National Key Laboratory of Underwater Acoustic Technology, Harbin Engineering University, Harbin 150001, China.
The flextensional transducer (FT) is a typical low-frequency transmitting transducer that is capable of high-power operation due to its capacity for displacement amplification. This article uses the structural configuration of the class IV FT as the basis for designing a ring transducer, which is a circular structure comprising a multitude of class IV flextensional structures as well as circular acoustic radiation structures. The flextensional structure drives the circular acoustic radiation structure, which in turn generates sound waves at low frequencies.
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January 2025
Institute of Intelligent Manufacturing Technology, Shenzhen Polytechnic University, Shenzhen 518000, China.
This paper introduces a novel energy-efficient lightweight, void hole avoidance, localization, and trust-based scheme, termed as Energy-Efficient and Trust-based Autonomous Underwater Vehicle (EETAUV) protocol designed for 6G-enabled underwater acoustic sensor networks (UASNs). The proposed scheme addresses key challenges in UASNs, such as energy consumption, network stability, and data security. It integrates a trust management framework that enhances communication security through node identification and verification mechanisms utilizing normal and phantom nodes.
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December 2024
School of Computer Science, University of South China, Hengyang 421001, China.
In exploiting large propagation delays in underwater acoustic (UWA) networks, the time-domain interference alignment (TDIA) mechanism aligns interference signals through delay-aware slot scheduling, creating additional idle time for improved transmission at the medium access control (MAC) layer. However, perfect alignment remains challenging due to arbitrary delays. This study enhances TDIA by incorporating power allocation into its transmission scheduling framework across the physical and MAC layers, following the cross-layer design principle.
View Article and Find Full Text PDFJ Acoust Soc Am
January 2025
School of Integrated Circuits, Tsinghua University, Beijing 100084, China.
In shallow water, reverberation complicates the detection of low-intensity, variable-echo moving targets, such as divers. Traditional methods often fail to distinguish these targets from reverberation, and data-driven methods are constrained by the limited data on intruding targets. This paper introduces the online robust principal component analysis and multimodal anomaly detection (ORMAD) method to address these challenges.
View Article and Find Full Text PDFJ Acoust Soc Am
January 2025
Center for Acoustics Research and Education, University of New Hampshire, Durham, New Hampshire 03823, USA.
Fishes and aquatic invertebrates utilize acoustic particle motion for hearing, and some additionally detect sound pressure. Yet, few underwater soundscapes studies report particle motion, which is often assumed to scale predictably with pressure in offshore habitats. This relationship does not always exist for low frequencies or near reflective boundaries.
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