Searched for: subject:"Underwater%5C+acoustics"
(1 - 12 of 12)
document
Han, Jing (author), Chepuri, Sundeep Prabhakar (author), Leus, G.J.T. (author)
Orthogonal signal-division multiplexing (OSDM) has recently emerged as a promising modulation scheme for underwater acoustic communications. Although providing more flexibility in system design, it suffers from a special interference structure over time-varying channels. To enable reliable OSDM equalization, we propose a joint channel impulse...
journal article 2020
document
Ebihara, Tadashi (author), Ogasawara, Hanako (author), Leus, G.J.T. (author)
In this paper, we propose a novel underwater acoustic (UWA) communication scheme that achieves energy and spectrum efficiency simultaneously by combining Doppler-resilient orthogonal signal division multiplexing (D-OSDM) and multiple-input-multiple-output (MIMO) signaling. We present both the transmitter processing and the receiver processing...
review 2020
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Han, J. (author), Chepuri, S.P. (author), Zhang, Qunfei (author), Leus, G.J.T. (author)
Orthogonal signal-division multiplexing (OSDM) is a promising modulation scheme that provides a generalized framework to unify orthogonal frequency-division multiplexing (OFDM) and single-carrier frequency-domain equalization. By partitioning each data block into vectors, it allows for a flexible configuration to trade off resource management...
journal article 2019
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Han, J. (author), Zhang, Lingling (author), Zhang, Qunfei (author), Leus, G.J.T. (author)
Orthogonal signal-division multiplexing (OSDM) is a generalized modulation scheme to bridge the gap between orthogonal frequency-division multiplexing (OFDM) and single-carrier frequency-domain equalization. It allows significantly more flexibility in system design; however, over doubly-selective channels, it suffers from a special signal...
journal article 2019
document
Gaida, T.C. (author), Ali, Tengku Afrizal Tengku (author), Snellen, M. (author), Amiri Simkooei, A. (author), van Dijk, T.A.G.P. (author), Simons, D.G. (author)
Multi-frequency backscatter data collected from multibeam echosounders (MBESs) is increasingly becoming available. The ability to collect data at multiple frequencies at the same time is expected to allow for better discrimination between seabed sediments. We propose an extension of the Bayesian method for seabed classification to multi...
journal article 2018
document
Gaida, T.C. (author), Snellen, M. (author), van Dijk, Thaiënne A.G.P. (author), Simons, D.G. (author)
Extensive seabed sediment mapping is highly relevant to describe marine ecosystems and to quantify the distribution and extent of benthic habitats. Compared to traditional mapping methods, primarily based on bed sampling, multibeam echo sounding (MBES) is a time-efficient tool to acquire high-resolution bathymetric and backscatter data over...
journal article 2018
document
Ebihara, T. (author), Leus, G.J.T. (author)
Underwater acoustic (UWA) channels are characterized by a severe spread in time and frequency, and are usually labeled as “doubly spread channels.” In this paper, we propose Doppler-resilient orthogonal signal-division multiplexing (D-OSDM), to provide a highly reliable communication environment in doubly spread channels for UWA communication. D...
journal article 2015
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Ramezani, H. (author), Leus, G. (author)
In this paper, we analyze the problem of acoustic ranging between sensor nodes in an underwater environment. The underwater medium is assumed to be composed of multiple isogradient sound speed profile (SSP) layers where in each layer the sound speed is linearly related to the depth. Furthermore, each sensor node is able to measure its depth and...
journal article 2012
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Simons, D.G. (author), Snellen, M. (author), Ainslie, M.A. (author)
Sound backscattered from the seabed has been measured in a 10x10-nmi2 region of the North Sea, characterized by a variety of bottom types, including mud, sand, and gravel. The backscattering strength measurements are made by a forward- looking sonar, operating at 100 kHz and tilted at an angle of 30 from the horizontal. Fifty bottom-grab samples...
journal article 2007
document
Otto, K. (author), Larsson, E. (author)
A flexible solver for the Helmholtz equation is presented. The implementation of the solver is done in an object-oriented style, allowing for easy adaptation to different application problems. The solution methods that are employed are fast compared with standard solution techniques. The viability of the solver is demonstrated for realistic...
conference paper 2006
document
Groen, J. (author)
In recent years, sonar performance has mainly improved via a significant increase in array ap-erture, signal bandwidth and computational power. This thesis aims at improving sonar array processing techniques based on these three steps forward. In applications such as anti-submarine warfare and mine hunting motion of the sonar needs to be...
doctoral thesis 2006
document
van Stralen, M.J.N. (author)
doctoral thesis 1997
Searched for: subject:"Underwater%5C+acoustics"
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