Very-High-Frequency Single-Input–Multiple-Output Acoustic Communication in Shallow Water

Rudander, Jacob; Walree, Paul van; Husøy, Thor; Orten, Pål

doi:10.1109/joe.2018.2855298

Cited by 8 publications

(4 citation statements)

References 33 publications

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“…In the last twenty years, a vast literature has focused on underwater acoustic sensor networks and communication systems, but lately more and more solutions have focused on the adaptivity of the communication system and networking protocols based on the changing environment [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Design method for long-term evaluation of underwater acoustic communications and networks in a Norwegian fjord environment

Tomasi,

Øyerhamn,

Otnes

2024

Proceedings of the 10th Convention of the European Acoustics Association Forum Acusticum 2023

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Fjords often have difficult underwater acoustic propagation properties, such as the acoustic shadow zones created by highly dynamic bathymetry and thermocline/halocline. In addition, shallow-water coastal underwater acoustic horizontal communications are characterized by several reflections at the boundaries creating complex and timevarying multipath channel structures. We present an iterative simulation and experiment-based method for designing and evaluating an underwater acoustic communication system and the network layers built on it. First, we present the sound speed profiles collected throughout the year in the fjord at Austevoll in western Norway. Then we discuss the setup used to collect acoustic channel impulse responses in the frequency band 55-65 kHz in the same geographical area. We then provide the results of numerical modeling for the acoustic propagation and present the methodology that we plan to implement in the next few years for a long-term evaluation and improvement of acoustic sensor networks in fjord environments.

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Section: Introductionmentioning

confidence: 99%

Design method for long-term evaluation of underwater acoustic communications and networks in a Norwegian fjord environment

Tomasi,

Øyerhamn,

Otnes

2024

Proceedings of the 10th Convention of the European Acoustics Association Forum Acusticum 2023

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“…Turbo equalization is derived from turbo decoder by employing a maximum a posteriori (MAP) equalizer as replacement of one standalone MAP docoder in the typical decoder processing [6,7]. In order to realize computational complexity in large time-delay channel, soft-input-soft-output (SISO) equalizer is introduced into the iteration structure based on minimum mean squared error (MMSE) criterion [8][9][10], least symbol error rate (LSER) criterion [11,12] and so on. The chief drawback of traditional DFEs is error propagation of the feedback filter (FBF) when extensive inaccurate hard-decision symbols occurred.…”

Section: Introductionmentioning

confidence: 99%

Virtual Space-Time Diversity Turbo Equalization for Underwater Acoustic Communications

Han

Jiang

2023

Preprint

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A virtual space-time diversity soft direct-adaptation turbo euqalization (SDATEQ) is proposed for single-input-single-output (SISO) underwater acoustic (UWA) communications based on soft fractionally-spaced decision-feedback equalizer (SFSDFE) and virtual time-reversal mirror (VTRM). The SFSDFE combined with recursive least-squares (RLS) algorithm is employed to achieve virtual space diversity and increases the mutual information (MI) of iterations for faster convergence. Bidirectional structure with VTRM is exploited to mitigate error propagation phenomenon of DFE. An interpolator and digital phase locked loop (DPLL) are embedded into the euqalizer to overcome the residual Doppler frequency shift and recover the timing distortion. Results of simulations and field lake trial show that the proposed algothrim achieves better performance than Soft-DATEQ under the same equalizer order, and the bit error rate (BER) of 1500-m lake trial decreases from 1.50×10 -2 to 2.22×10 -5 .

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“…Turbo equalization is derived from turbo decoders by employing a maximum a posteriori (MAP) equalizer as a replacement of one stand-alone MAP decoder in typical decoder processing [13,14]. In order to realize computational complexity in large time-delay channels, a soft-input soft-output (SISO) equalizer is introduced into the iteration structure based on the minimum mean squared error (MMSE) criterion [15][16][17], least symbol error rate (LSER) criterion [18,19] and so on. In some scenarios of high SNR, the adaptive equalizers based on the LSER criterion achieve better BER performance than the MMSE.…”

Section: Introductionmentioning

confidence: 99%

Virtual Space-Time DiversityTurbo Equalization Using Cluster Sparse Proportional Recursive Least Squares Algorithm for Underwater Acoustic Communications

Han,

Tao,

Zhang

et al. 2023

Applied Sciences

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The oceanic positioning, navigation and timing (PNT) network requires high-quality underwater acoustic message transmission. Turbo equalization technology has exhibited superior performance for underwater acoustic (UWA) communications compared with conventional channel equalizers. To overcome the performance reduction caused by severe doubly selective UWA channels, the virtual space-time diversity soft direct-adaptation turbo equalization is proposed for UWA communications. The proposed scheme improves the ability of the typical turbo equalizer to deal with both Doppler and multipath effects for time varying channels. We utilize a fractionally spaced soft interference cancellation equalizer (FS-SE) instead of a hard decision to constitute the soft-input soft-output (SISO) equalizer. Combined with another virtual time-reversal mirror equalizer component, we can obtain virtual space and time diversity with only a single receiving transducer and mitigate the error propagation phenomenon of the feedback filter. To satisfy the sparse UWA channel, the ℓp,q-PRLS algorithm is applied to adaptive updates for FS-SE. In the proposed scheme, an adjustable interpolator and digital phase-locked loop are embedded into the equalizer to overcome the residual Doppler frequency shift and recover the timing distortion. Results of simulations and field lake trial show that the proposed scheme achieves better performance than existing ones under the same equalizer order.

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Very-High-Frequency Single-Input–Multiple-Output Acoustic Communication in Shallow Water

Cited by 8 publications

References 33 publications

Design method for long-term evaluation of underwater acoustic communications and networks in a Norwegian fjord environment

Design method for long-term evaluation of underwater acoustic communications and networks in a Norwegian fjord environment

Virtual Space-Time Diversity Turbo Equalization for Underwater Acoustic Communications

Virtual Space-Time DiversityTurbo Equalization Using Cluster Sparse Proportional Recursive Least Squares Algorithm for Underwater Acoustic Communications

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