Equalizer for real time high rate transmission in underwater communications

Geller, Benoît; Capellano, V.; Jourdain, Geneviève

doi:10.1109/icassp.1995.479560

Cited by 9 publications

(5 citation statements)

References 2 publications

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“…It is important to note that in contrast to previous works [2], [8], [9], [11]- [13], the calculation of the MSE of equation ( 5) encompasses all synchronisation modes (Data-Aided (DA), Non-Data-Aided (NDA) and Code-Aided(CA)); in particular, for the CA mode, the probability of the constellation point x ∈ χ can be computed using the LLR values (see (3)) at the output of the channel decoder. With some basic mathematical derivations, we can obtain ∂J ∂f k , ∂J ∂g k and ∂J ∂θ k .…”

Section: The Proposed Adaptive Turbo Equalizermentioning

confidence: 68%

“…Furthermore, for time-varying channels such as underwater acoustic channels, algorithms using constant step-sizes are unable to achieve a good trade-off between the performance and the convergence speed. However, most of the existing literature concerned with MMSE adaptive step-size filters [8], [9], [15]- [17] did not consider the case of turbo equalization; [18] (resp. [19]) proposed an iterative equalization scheme based on the least-symbol-error-rate [20] with a constant (resp.…”

Section: Introductionmentioning

confidence: 99%

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Adaptive Step-size Iterative Equalization for Underwater Communication

Arbi

Geller

2021

OCEANS 2021: San Diego – Porto

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This paper presents a fully adaptive Minimum Mean Square Error (MMSE) iterative equalization with a joint phase estimation, using various adaptive step-sizes scheme. To meet the requirement of fast convergence and low MSE over time-varying channels, we propose an original self-optimized algorithm whose step-sizes are updated adaptively and assisted by soft-information provided by the channel decoder in an iterative manner. Simulation results show that our proposal achieves better performance over various multipath time-varying channels, compared to the conventional equalizer using a fixed step-size.

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Section: The Proposed Adaptive Turbo Equalizermentioning

confidence: 68%

Section: Introductionmentioning

confidence: 99%

Adaptive Step-size Iterative Equalization for Underwater Communication

Arbi

Geller

2021

OCEANS 2021: San Diego – Porto

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“…Because of problems often imposed by the channel's strong multipath, we instead opted to pair all adaptive phase detection functionality with the equalizer. Geller et al in an earlier work in high-speed underwater communications employed similar rationale [9], and other works described in [1] locate PLL functionality in the equalizer rather than solely using adaptive DFE [10].…”

Section: Receiver Modelmentioning

confidence: 97%

“…Equalizer #5 is a DFE with densely spaced forward taps. Similar to the heuristic tap placement approach in [11] and [9], Equalizer #5's sparsely spaced feedback taps are located at symbol intervals with highest channel impulse response magnitudes in a window of 0 ms (packet start) to 195 ms after the peak. The adaptation rate μ is 0 < μ < 2 / N total .…”

Section: Equalizer Comparisonmentioning

confidence: 99%

Multi-stage and sparse equalizer design for communication systems in reverberant underwater channels

Nieman

Perrine

Lent

et al. 2010

2010 IEEE Workshop on Signal Processing Systems

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0 5 10 15 0 0.5 1 0.2 0.4 0.6 0.8 1 S y s te m ti m e ( s ) Ch an ne l im pu lse re sp on se (m s) Direct path First echo Reverberation Fig. 1. Channel impulse response magnitude variation vs. time from a boat to a stationary platform at 820 ft (250 m) range. The direct path and first echo are approx. stationary over the system time whereas the reverberation varies largely over the system time. ABSTRACTCoherent underwater communication systems in shallow water must compensate for several impairments, including Doppler shift and reverberant channels. In this paper, we quantify tradeoffs in communication performance vs. computational complexity in designing receivers to compensate for these impairments. Our communication system is unidirectional, single-carrier, wideband, and packet-based. We use 1.5 hours of recorded data from an experimental system on a public lake with a moving transmitter and stationary receiver. Our contributions include acoustic channel modeling and a tradeoff analysis for Doppler shift estimation, multi-stage equalizers and sparse equalizers. We compare multi-stage and sparse equalizers against traditional equalizers.

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“…Also in practice, acoustic waves are strongly disturbed by several physical phenomena: significant attenuation, noise, multipath, Doppler effect, low propagation speed of acoustic waves (around 1500 m/s), triply selective channel (time, frequency, space). All these combined effects limit data rates to just a few tens of kbits/s per km [13][14][15][16]. We also have developed a MIMO (Multi-input Multi-output) acoustic platform and obtained theoretical results about equalizing structures to face the harsh multipath acoustic underwater propagation.…”

Section: Underwater Acoustic Communicationmentioning

confidence: 99%

Bioglider: An Integrated Glider Solution for Enhancing Environmental Knowledge

Ponçon,

Mortier,

Picheral

et al. 2023

OCEANS 2023 - MTS/IEEE U.S. Gulf Coast

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This paper presents a technological solution for the observation and monitoring of the marine ecosystem. Three complementary devices, one optic imaging and one scientific acoustic instrument as well as one acoustic communication modem, have been integrated on glider platforms, providing qualitative and quantitative zooplankton and fish ecology observations, which are especially relevant in Nordic and Arctic polar regions. This 'Bioglider' solution has been tested on two available gliders. Another essential platform component for ocean observing are subsurface mooring lines which can complement glider observations in terms of temporal scales. Most of the time, they cannot have surface expressions in these regions because of sea-ice cover or harsh sea conditions, prohibiting real time data delivery. Underwater acoustic communication can allow the glider to serve as a data messenger, retrieving data from the moorings, complementing its measuring capacities. The Bioglider data transmission protocol and the Hydro-Acoustic Link Simulator were successfully tested in different test scenarios. We also developed a MIMO (Multi-input Multi-output) acoustic platform and obtained theoretical results about equalizing structures to face the harsh multipath acoustic underwater propagation. These developments address the challenges posed by sea-ice cover, harsh sea conditions, and maritime traffic, ensuring near real -time data delivery and enabling comprehensive observations of the marine environment. The Bioglider sensor solution and Bioglider data transmission solution have been implemented or designed for the existing and commercially available gliders and are validated by first promising results from an operational, technological and scientific point of view.

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Equalizer for real time high rate transmission in underwater communications

Cited by 9 publications

References 2 publications

Adaptive Step-size Iterative Equalization for Underwater Communication

Adaptive Step-size Iterative Equalization for Underwater Communication

Multi-stage and sparse equalizer design for communication systems in reverberant underwater channels

Bioglider: An Integrated Glider Solution for Enhancing Environmental Knowledge

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