Stochastic simulation of acoustic communication in turbulent shallow water

A B S T R A C TThe past 30 years have seen a growing interest in underwater acoustic communications because of its applications in marine research, oceanography, marine commercial operations, the offshore oil industry and defense. Continued research over the years has resulted in improved performance and robustness as compared to the initial communication systems. In this paper, we aim to provide an overview of the key developments in point-to-point communication techniques as well as underwater networking protocols since the beginning of this decade. We also provide an insight into some of the open problems and challenges facing researchers in this field in the near future.protocols for such networks. In this paper, we do not attempt to provide an exhaustive survey of all research in the field, but instead concentrate on ideas and developments that are likely to be the keystone of future underwater communication networks. II. Underwater CommunicationsHigh-speed communication in the underwater acoustic channel has been challenging because of limited bandwidth, extended multipath, refractive properties of the medium, severe fading, rapid time variation and large Doppler shifts. In the initial years, rapid progress was made in deep water communication, but the shallow water channel was considered difficult. In the past decade, significant advances have been made in shallow water communication.

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“…A good review of channel modeling work prior to the year 2000 has been presented in Bjerrum-Niese and Lutzen (2000).…”

Section: Channel Modelingmentioning

confidence: 99%

Underwater Acoustic Communications and Networking: Recent Advances and Future Challenges

Chitre¹,

Shahabudeen²,

Stojanovic³

2008

mar technol soc j

523

222

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“…Some of the most popular models are GRAB [10], RAY [11] or Bellhop [12], but different authors propose their own models to fit their specific needs. For example, the model by Niese and Lützen [13] uses a Monte Carlo method to predict signal transmission conditions and fading for turbulent shallow water environments, and the model by Chitre [14], valid for very shallow water environments, includes time-varying statistical effects and non-Gaussian noise.…”

Section: Introductionmentioning

confidence: 99%

Accurate detection of spread-spectrum modulated signals in reverberant underwater environments

et al. 2015

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a b s t r a c tIn those positioning systems based on the detection of acoustic signals, an accurate detection of the arrival times is crucial for a correct estimation of the distance between nodes, and therefore, for the precise estimation of the node that wants to be located. In order to obtain this arrival time more accurately, acoustic signals can be coded using pseudorandom noise, but these coded signals are still affected by underwater channel phenomena. In this work, the detection of spread-spectrum modulated signals is analyzed in underwater environments that are highly affected by multipath and reverberation. A spread-spectrum signal, which consist of a modulated Kasami code, has been emitted through two different pools, reaching a receiver where it has been captured after following several line-of-sight and nonline-of-sight paths. Then, a correlation process has been performed offline to provide information about the arrival times (times-of-flight) that form the multipath structure. These times-of-flight are compared with those provided by an underwater acoustic propagation model, in order to test the performance of this model and its capacity to predict the outcome of signal detection in underwater environments with a strong multipath and reverberation component. That way, the validated propagation model could be later used in future studies to predict the detection of spread-spectrum signals and the performance of systems that use them in these adverse environments.

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“…In the context of underwater acoustic communications, this represents ͑in an averaged sense͒ the front end of an optimal receiver. 3 Intersymbol interference associated with multipath propagation is an important and limiting feature in underwater acoustic communication, 4,5 motivating study of alternate techniques, e.g., involving time-reversal, 6,7 to overcome this effect. Also note that the IIRF, because of its strong relation to bottom properties, has been used in geoacoustic parameter inversion.…”

Section: Introductionmentioning

confidence: 99%

Measurement and simulation of the channel intensity impulse response for a site in the East China Sea

Choi

Dahl

2006

The Journal of the Acoustical Society of America

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A model for the channel intensity impulse response I c ͑t͒ is presented that is generally applicable for source-receiver ranges less than ten water depths. The separate impulse response functions from each arrival, such as the single surface bounce or surface-to-bottom bounce, are modeled using bistatic scattering concepts and are incoherently summed for the total response function. The expression I c ͑t͒ is equivalent to a time-averaged response and embodies the boundary scattering and reflection physics corresponding to the center frequency at which computations are made. To compare with observations, I c ͑t͒ is convolved with representations of the 8-and 16-kHz continuous wave ͑CW͒ pulses, and an 8 -16-kHz frequency-modulated ͑FM͒ pulse, that were used in the Asian Sea International Acoustics Experiment conducted in the East China Sea ͑depth 105 m͒. For the FM case the computation frequency is 12 kHz, the center frequency of the FM pulse. It is found that six primary arrivals dominate the response for ranges less than about 1 km. With modeling of I c ͑t͒ limited to these paths, the basic structure of I c ͑t͒ is set by bottom properties and acquisition geometry with some changes in intrapath time spreading that depend on sea surface conditions.

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Stochastic simulation of acoustic communication in turbulent shallow water

Cited by 28 publications

References 15 publications

Underwater Acoustic Communications and Networking: Recent Advances and Future Challenges

Underwater Acoustic Communications and Networking: Recent Advances and Future Challenges

Accurate detection of spread-spectrum modulated signals in reverberant underwater environments

Measurement and simulation of the channel intensity impulse response for a site in the East China Sea

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