scholarly journals Underwater Optical Wireless Communications with Chromatic Dispersion and Time Jitter

Computation ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 35 ◽  
Author(s):  
Roumelas ◽  
Nistazakis ◽  
Stassinakis ◽  
Volos ◽  
Tsigopoulos
Keyword(s):  
Wireless Communications ◽  
Communication Systems ◽  
Chromatic Dispersion ◽  
Mathematical Expression ◽  
Optical Wireless ◽  
Optical Wireless Communications ◽  
Time Jitter ◽  
High Data ◽  
Data Rates ◽  
Very High

The obsolete communication systems used in the underwater environment necessitates the development and use of modern telecommunications technologies. One such technology is the optical wireless communications, which can provide very high data rates, almost infinite bandwidth and very high transmission speed for real time fast and secure underwater links. However, the composition and the optical density of seawater hinder the communication between transmitter and receiver, while many significant effects strongly mitigate the underwater optical wireless communication (UOWC) systems’ performance. In this work, the influences of chromatic dispersion and time jitter are investigated. Chromatic dispersion causes the temporal broadening or narrowing of the pulse, while time jitter complicates the detection process at the receiver. Thus, the broadening of the optical pulse due to chromatic dispersion is studied and the influence of the initial chirp is examined. Moreover, the effect of the time jitter is also taken into consideration and for the first time, to the best of our knowledge, a mathematical expression for the probability of fade is extracted, taking into account the influence of both of the above-mentioned effects for a UOWC system. Finally, the appropriate numerical results are presented.

scholarly journals Time and Spatial Jitter Influence on the Performance of FSO Links with DF Relays and OC Diversity over Turbulence Channels

Photonics ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 318
Author(s):  
Panagiotis J. Gripeos ◽  
Hector E. Nistazakis ◽  
Andreas D. Tsigopoulos ◽  
Vasilis Christofilakis ◽  
Evgenia Roditi
Keyword(s):  
Critical Factor ◽  
Weather Conditions ◽  
Optical Wireless Communications ◽  
Time Jitter ◽  
Diversity Techniques ◽  
High Data ◽  
Mathematical Expressions ◽  
Data Rates ◽  
Turbulence Effect ◽  
The Many

FSO communication is a viral technology among optical wireless communications, gathering the interest of both researchers and manufacturers. This is because of the many advantages associated with FSO communication, including high data rates, reliability, safety, and economy. However, there are several unavoidable drawbacks that shadow the performance of FSO systems. For example, atmospheric turbulence is a well-known problem related to the weather conditions of the channel, which causes the scintillation effect. Also, spatial jitter due to pointing errors is a critical factor of the link’s performance, caused by occasional misalignments between the transmitter and the receiver. Moreover, time jitter is another limiting agent that deteriorates the total throughput, inducing bit stream misdetections, caused by the arrival of out-of-sync pulses. All three effects have been exhaustively studied and many statistical models and interesting solutions have been proposed in the literature to estimate their magnitude and compensate for their impact. In this work, the turbulence effect was treated by Málaga distribution, the spatial jitter effect was regulated by the non-zero boresight model, and the time jitter effect was modeled by the generalized Gaussian distribution. Various modulation schemes were studied, along with DF multi-hop and optimal combining diversity techniques at the receiver’s end. New, accurate mathematical expressions of average BER performance have been obtained, and valuable conclusions were drawn thanks to the presented numerical results.

Efficient Receiver Implementation for Mobile Applications

2009 ◽  
pp. 271-298
Author(s):  
Costas Chaikalis ◽  
Felip Riera-Palou
Keyword(s):  
Communication Systems ◽  
Low Complexity ◽  
Wireless Communication Systems ◽  
Channel Decoding ◽  
High Data ◽  
Data Rates ◽  
Channel Effects ◽  
Environment Simulation ◽  
Very High

Modern and future wireless communication systems such as UMTS and beyond 3G systems (B3G) are expected to support very high data rates to/from mobile users. This poses important challenges on the handset design as they should be able to attain an acceptable operating bit error rate (BER) while employing a limited set of resources (i.e. low complexity, low power) and often, with tight processing delay constraints. In this chapter we study how channel decoding and equalisation, two widely used mechanisms to combat the deleterious channel effects, can be made adaptable in accordance to the instantaneous operating environment. Simulation results are given demonstrating how receiver reconfigurability is a promising method to achieve complexity/delay efficient receivers while maintaining prescribed quality of service (QoS) constraints.

scholarly journals Underwater Optical Wireless Communications: Overview

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2261 ◽  
Author(s):  
Giuseppe Schirripa Spagnolo ◽  
Lorenzo Cozzella ◽  
Fabio Leccese
Keyword(s):  
Wireless Communications ◽  
Wireless Communication ◽  
Single Photon ◽  
Green Light ◽  
Low Latency ◽  
Optical Wireless Communication ◽  
Optical Wireless ◽  
Optical Wireless Communications ◽  
Data Rates ◽  
Absorption Window

Underwater Optical Wireless Communication (UOWC) is not a new idea, but it has recently attracted renewed interest since seawater presents a reduced absorption window for blue-green light. Due to its higher bandwidth, underwater optical wireless communications can support higher data rates at low latency levels compared to acoustic and RF counterparts. The paper is aimed at those who want to undertake studies on UOWC. It offers an overview on the current technologies and those potentially available soon. Particular attention has been given to offering a recent bibliography, especially on the use of single-photon receivers.

scholarly journals Effect of Environmental Parameters on the Performance of Optical Wireless Communications

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Hosam Abd Elrazek Mohamed Ali ◽  
El-Sayed Soliman A. Said ◽  
Mohamed Ebrahim Yousef
Keyword(s):  
Wireless Communications ◽  
Free Space ◽  
Communication Systems ◽  
High Speed ◽  
System Analysis ◽  
Environmental Parameters ◽  
Weather Conditions ◽  
Optical Wireless ◽  
Free Space Optical ◽  
Optical Wireless Communications

Free space optical communication systems are the future of the communication systems which can meet the needs of the end users who are demanding high bandwidths to support high-speed communication. These merits are due to its numerous advantages as well as their better performance. This paper studies the effect of environmental parameters like rain, fog, haze, snow, and dust on the performance of optical wireless communications using Opti-system program. This work considers the effect of visibility as well as operating wavelengths on atmospheric attenuation in different weather conditions for free space optical link. For different weather conditions the max distance between transmitter and receiver can also be estimated. The system analysis depicted the better performance of the Multi-Input/Multi-Output (MIMO) configurations compared to Single Input/Single Output (SISO) at different weather conditions.

scholarly journals Time Jitter, Turbulence and Chromatic Dispersion in Underwater Optical Wireless Links

Technologies ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 3 ◽  
Author(s):  
George D. Roumelas ◽  
Hector E. Nistazakis ◽  
Argyris N. Stassinakis ◽  
George K. Varotsos ◽  
Andreas D. Tsigopoulos ◽  
...  
Keyword(s):  
Wireless Communication ◽  
Communication Systems ◽  
Pulse Propagation ◽  
Chromatic Dispersion ◽  
Estimation Procedure ◽  
Communication Link ◽  
Optical Wireless Communication ◽  
Optical Wireless ◽  
Time Jitter ◽  
Turbulence Effects

The performance of an underwater optical wireless communication link is investigated by taking into account—for the first time and to the best of our knowledge—the simultaneous influence of the chromatic dispersion, the time jitter and the turbulence effects, by assuming chirped longitudinal Gaussian pulse propagation as information carriers. The estimation procedure is presented and a novel probability density function is extracted in order to describe the irradiance fluctuations at the receiver side. Furthermore, the availability of the link is investigated by means of its probability of fade and various numerical results are presented using typical parameters for the underwater optical wireless communication systems.

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