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Proceedings ArticleDOI

Underwater Wireless Optical Communication Systems: A Survey

23 Jul 2020-pp 1-7
TL;DR: This review article focuses on underwater optical wireless communications (UWOCs) using optical waves as transmission medium, which have a muchHigher communication frequency and therefore a much higher data rate compared to RF and acoustic counter-parts.
Abstract: Underwater wireless communication (UWC) means the transmission of data using wireless channels through the underwater, i.e. radio frequency waves (RF), acoustic waves and optical waves in an unguided water environment. In this review article we focus on underwater optical wireless communications (UWOCs) using optical waves as transmission medium. UWOCs have a much higher communication frequency and therefore a much higher data rate compared to RF and acoustic counter-parts. Due to this high-speed data transfer advantage, UWOC has been very attractive over the past few years. Many applications have been proposed in UWOC systems for protection of the environment, underwater exploration, emergency alerts and military operations etc. However, underwater channels also suffer from extreme absorption and dispersion. In recent years, a variety of innovative methods of network architecture have been developed to meet these technological challenges, which are different from standard terrestrial, open space optical communications. In this article we give a detailed overview of various research activities on UWOC.
Citations
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Journal ArticleDOI
TL;DR: In this article, the authors investigated the performance of the dual-hop UOWC system with simultaneous lightwave information and power transfer (SLIPT), where the information and energy are transmitted in different phases.
Abstract: The most significant challenge of underwater optical wireless communication (UOWC) system is to overcome its limited coverage. To expand the achievable communication range, we investigate the performance of the dual-hop UOWC system with simultaneous lightwave information and power transfer (SLIPT). The time splitting (TS) method is adopted for wireless power transfer in the proposed system, where the information and energy are transmitted in different phases. A suitable transmission strategy is designed for the model without additional power supply, which contains three phases, i.e. information transmission, energy transmission, and forwarding process. The expressions of the average bit error rate (BER) at the target node and the energy harvested by the relay node are derived over underwater attenuation channel. Then, the effects of the TS factor and the distances on the system performance are investigated in two sub-problems, which minimize the average BER while satisfying the energy harvesting and transmitting rate constraints. Numerical results indicate the performance improvement by adopting the relay node with SLIPT.

6 citations

Journal ArticleDOI
TL;DR: A detailed literature review of the various kinds of active and passive attacks which hamper the confidentiality, integrity, authentication and availability of both underwater and A-W WCNs is provided.
Abstract: We present a first detailed survey that focuses on the security challenges faced by the underwater and air-water (A-W) wireless communication networks (WCNs), as well as the countermeasures proposed to date. Specifically, we provide a detailed literature review of the various kinds of active and passive attacks which hamper the confidentiality, integrity, authentication and availability of both underwater and A-W WCNs. For clarity of exposition, this survey paper is mainly divided into two parts. The first part of the paper is essentially a primer on underwater and A-W WCNs whereby we outline the benefits and drawbacks of the three promising underwater and A-W candidate technologies: radio frequency (RF), acoustic, and optical, along with channel modelling. To this end, we also describe the indirect (relay-aided) and direct mechanisms for the A-W WCNs along with channel modelling. This sets the stage for the second part (and main contribution) of the paper whereby we provide a thorough comparative discussion of a vast set of works that have reported the security breaches (as well as viable countermeasures) for many diverse configurations of the underwater and A-W WCNs. Finally, we highlight some research gaps in the open literature and identify some open problems for the future work.

4 citations

Proceedings ArticleDOI
28 Jul 2021
TL;DR: In this article, the authors investigated the statistical distribution of the turbulence channel of the UOWC system using the proposed experimental setup in a water tank, where different turbulence conditions are generated by changing the temperature and the salinity gradients of the injected water flow.
Abstract: The turbulence is an intractable issue for underwater optical wireless communication (UOWC), and limited literature has been focused on the probability density function (PDF) of the received signal. This paper investigates the statistical distribution of the turbulence channel of the UOWC system using the proposed experimental setup in a water tank. Different turbulence conditions are generated by changing the temperature and the salinity gradients of the injected water flow. Some general distributions such as Lognormal, Log-logistic, Gamma, Exponential Weibull and Generalized Gamma distributions adopted for curve fitting are thoroughly compared. Furthermore, the coherence time of UOWC channel under different turbulence conditions is discussed as well.

3 citations

Journal ArticleDOI
TL;DR: In this article, the authors proposed an underwater wireless optical communication (UWOC) system using an optical transceiver with an optimum transmission rate for the deep sea with near-pure water properties.
Abstract: The challenge for next-generation underwater optical wireless communication systems is to develop optical transceivers that can operate with low power consumption by maximizing the transmission capacity according to the transmission distance between transmitters and receivers. This study proposes an underwater wireless optical communication (UWOC) system using an optical transceiver with an optimum transmission rate for the deep sea with near-pure water properties. As a method for actualizing an optical transceiver with an optimum transmission rate in a UWOC system, time-domain hybrid pulse amplitude modulation (PAM) (TDHP) using a transmission rate and distance-adaptive intensity modulation/direct detection optical transceiver is considered. In the TDHP method, variable transmission capacity is actualized while changing the generation ratio of two intensity-modulated signals with different noise immunities in the time domain. Three different color laser diodes (LDs), red, blue, and green are used in an underwater channel transmission transceiver that comprises the LD and a photodiode. The maximum transmission distance while changing the incidence of PAM 2 and PAM 4 signals that calibrate the TDHP in a pure transmission line and how the maximum transmission distance changes when the optical transmitter/receiver spatial optical system is altered from the optimum conditions are clarified based on numerical calculation and simulation. To the best knowledge of the authors, there is no other research on data-rate and distance adaptive UWOC system that applies the TDHP signal with power optimization between two modulation formats.

3 citations

Journal ArticleDOI
TL;DR: A vision as well as various obstacles in the domain of underwater optical wireless communication are presented, a detailed overview, and comparison of underwater communications techniques (UOWC) links, basic modulation technique techniques, and c pursuits on UWOC are presented.
Abstract: Abstract Underwater wireless optical communication (UOWC) systems have lately garnered a significant amount of attention for both academic purposes and trial applications. Although the idea is not new, the fact that seawater has a smaller window of absorption for blue-green light has reawakened interest in it, and it has grown an essential attraction because of its high bandwidth, it can cover a wide variety of underwater activities as compared to radio frequency and acoustic technologies. To monitor pollution, maintain oil pipelines, monitor climate change, conduct offshore investigations, and conduct oceanography research, the wireless transmission of information underwater technology is of importance to the military, industrial, and scientific organizations all around the world. The use of wavelengths of visible light to transmit secure data across point-to-point connections in underwater optical wireless communication (UOWC) compares well with the usage of free-space optical (FSO) communications. However, UWOC systems also have a huge amount of absorption and scattering introduced by the aquatic channels. Different from standard terrestrial free-space optical communication, many unique system design strategies have been investigated in recent years to solve these technological issues. This article presents a vision as well as various obstacles in the domain of underwater optical wireless communication, a detailed overview, and comparison of underwater communications techniques (UOWC) links, basic modulation technique techniques, and c pursuits on UWOC.

1 citations

References
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Journal ArticleDOI
TL;DR: The use of ML detection in spatial diversity reception to reduce the diversity gain penalty caused by correlation between the fading at different receivers is described.
Abstract: In free-space optical communication links, atmospheric turbulence causes fluctuations in both the intensity and the phase of the received light signal, impairing link performance. We describe several communication techniques to mitigate turbulence-induced intensity fluctuations, i.e., signal fading. These techniques are applicable in the regime in which the receiver aperture is smaller than the correlation length of fading and the observation interval is shorter than the correlation time of fading. We assume that the receiver has no knowledge of the instantaneous fading state. When the receiver knows only the marginal statistics of the fading, a symbol-by-symbol ML detector can be used to improve detection performance. If the receiver has knowledge of the joint temporal statistics of the fading, maximum-likelihood sequence detection (MLSD) can be employed, yielding a further performance improvement, but at the cost of very high complexity. Spatial diversity reception with multiple receivers can also be used to overcome turbulence-induced fading. We describe the use of ML detection in spatial diversity reception to reduce the diversity gain penalty caused by correlation between the fading at different receivers.

1,490 citations


Additional excerpts

  • ...[28] for open space optical communication systems....

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  • ...Kahn,2006 [28] MLSD (maximum likelihood sequence detection) To increase detection efficiency, it is possible to use ML symbols when the immediate fading is unknown but the marginal fading statistics are known, and MLSDs can be used when turbulenceinduced fading is a common temporal distribution....

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Journal ArticleDOI
TL;DR: An exhaustive overview of recent advances in underwater optical wireless communication is provided and a hybrid approach to an acousto-optic communication system is presented that complements the existing acoustic system, resulting in high data rates, low latency, and an energy-efficient system.
Abstract: Underwater wireless information transfer is of great interest to the military, industry, and the scientific community, as it plays an important role in tactical surveillance, pollution monitoring, oil control and maintenance, offshore explorations, climate change monitoring, and oceanography research. In order to facilitate all these activities, there is an increase in the number of unmanned vehicles or devices deployed underwater, which require high bandwidth and high capacity for information transfer underwater. Although tremendous progress has been made in the field of acoustic communication underwater, however, it is limited by bandwidth. All this has led to the proliferation of underwater optical wireless communication (UOWC), as it provides higher data rates than the traditional acoustic communication systems with significantly lower power consumption and simpler computational complexities for short-range wireless links. UOWC has many potential applications ranging from deep oceans to coastal waters. However, the biggest challenge for underwater wireless communication originates from the fundamental characteristics of ocean or sea water; addressing these challenges requires a thorough understanding of complex physio-chemical biological systems. In this paper, the main focus is to understand the feasibility and the reliability of high data rate underwater optical links due to various propagation phenomena that impact the performance of the system. This paper provides an exhaustive overview of recent advances in UOWC. Channel characterization, modulation schemes, coding techniques, and various sources of noise which are specific to UOWC are discussed. This paper not only provides exhaustive research in underwater optical communication but also aims to provide the development of new ideas that would help in the growth of future underwater communication. A hybrid approach to an acousto-optic communication system is presented that complements the existing acoustic system, resulting in high data rates, low latency, and an energy-efficient system.

859 citations


"Underwater Wireless Optical Communi..." refers background in this paper

  • ...Optical communication is therefore a desirable alternative to acoustic remote communication [12]....

    [...]

Journal ArticleDOI
TL;DR: This paper provides a comprehensive and exhaustive survey of the state-of-the-art UOWC research in three aspects: 1) channel characterization; 2) modulation; and 3) coding techniques, together with the practical implementations of UowC.
Abstract: Underwater wireless communications refer to data transmission in unguided water environment through wireless carriers, i.e., radio-frequency (RF) wave, acoustic wave, and optical wave. In comparison to RF and acoustic counterparts, underwater optical wireless communication (UOWC) can provide a much higher transmission bandwidth and much higher data rate. Therefore, we focus, in this paper, on the UOWC that employs optical wave as the transmission carrier. In recent years, many potential applications of UOWC systems have been proposed for environmental monitoring, offshore exploration, disaster precaution, and military operations. However, UOWC systems also suffer from severe absorption and scattering introduced by underwater channels. In order to overcome these technical barriers, several new system design approaches, which are different from the conventional terrestrial free-space optical communication, have been explored in recent years. We provide a comprehensive and exhaustive survey of the state-of-the-art UOWC research in three aspects: 1) channel characterization; 2) modulation; and 3) coding techniques, together with the practical implementations of UOWC.

790 citations

Journal ArticleDOI
TL;DR: This paper investigates the bit error rate (BER) performance of FSO links with spatial diversity over log- normal atmospheric turbulence fading channels, assuming both independent and correlated channels among transmitter/receiver apertures.
Abstract: Free space optical (FSO) communications is a cost-effective and high bandwidth access technique, which has been receiving growing attention with recent commercialization successes. A major impairment in FSO links is the turbulence- induced fading which severely degrades the link performance. To mitigate turbulence-induced fading and, therefore, to improve the error rate performance, spatial diversity can be used over FSO links which involves the deployment of multiple laser transmitters/receivers. In this paper, we investigate the bit error rate (BER) performance of FSO links with spatial diversity over log- normal atmospheric turbulence fading channels, assuming both independent and correlated channels among transmitter/receiver apertures. Our analytical derivations build upon an approximation to the sum of correlated log-normal random variables. The derived BER expressions quantify the effect of spatial diversity and possible spatial correlations in a log-normal channel.

729 citations


"Underwater Wireless Optical Communi..." refers background in this paper

  • ...2007 [27] Performance study of error rate and free space optical communication....

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  • ...Random variations in the underwater medium are mainly due to temperature and salinity variations, while variations in the atmosphere are due to homogenization of temperature and pressure changes [27]....

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Journal ArticleDOI
TL;DR: Results of Monte Carlo simulations over ocean water paths of several tens of meters indicate that optical communication data rates >1 Gbit/s can be supported and are compatible with high-capacity data transfer applications that require no physical contact.
Abstract: We report error-free underwater optical transmission measurements at 1 Gbit/s (109 bits/s) over a 2 m path in a laboratory water pipe with up to 36 dB of extinction. The source at 532 nm was derived from a 1064 nm continuous-wave laser diode that was intensity modulated, amplified, and frequency doubled in periodically poled lithium niobate. Measurements were made over a range of extinction by the addition of a Mg(OH)2 and Al(OH)3 suspension to the water path, and we were not able to observe any evidence of temporal pulse broadening. Results of Monte Carlo simulations over ocean water paths of several tens of meters indicate that optical communication data rates >1 Gbit/s can be supported and are compatible with high-capacity data transfer applications that require no physical contact.

561 citations


"Underwater Wireless Optical Communi..." refers background in this paper

  • ...Frank Hanson1and Stojan Radic 2008 [29] Validated optical communication at 1Gbit / s through a 2 m pipe with a narrow beam extinguishing of up to 36 dB....

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