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The Effect Of Atmospheric Turbulence On The Performance Of Terrestrial Digital Optical Line Of Sight Communication Systems
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Book Synopsis The Effect of Atmospheric Turbulence on the Performance of Terrestrial Digital Optical Line of Sight Communication Systems by : Christopher John Lilly
Download or read book The Effect of Atmospheric Turbulence on the Performance of Terrestrial Digital Optical Line of Sight Communication Systems written by Christopher John Lilly and published by . This book was released on 1986 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Effect of Atmospheric Turbulence on the Performance of Terrestrial Digital Optical Line of Sight Communication Systems by : C. J. Lilly
Download or read book The Effect of Atmospheric Turbulence on the Performance of Terrestrial Digital Optical Line of Sight Communication Systems written by C. J. Lilly and published by . This book was released on 1986 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Index to Theses with Abstracts Accepted for Higher Degrees by the Universities of Great Britain and Ireland and the Council for National Academic Awards by :
Download or read book Index to Theses with Abstracts Accepted for Higher Degrees by the Universities of Great Britain and Ireland and the Council for National Academic Awards written by and published by . This book was released on 1988 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Effects of Atmospheric Turbulence on an Air-To-Air Optical Communication Link by : J. N. Kanavos
Download or read book The Effects of Atmospheric Turbulence on an Air-To-Air Optical Communication Link written by J. N. Kanavos and published by . This book was released on 1984 with total page 109 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents an analysis of the performance of an air-to-air optical communication link in the presence of atmospheric turbulence. As aircraft travel through the atmosphere, they encounter regions of atmospheric turbulence. While harmless to radio frequency communications, these regions of turbulence can cause both intensity and phase fluctuations within an optical beam. as a result, the communication link bit error rate rises. To evaluate the performance of such a link, a computer simulation was developed. By varying such parameters as the speed fo the aircraft, its altitude, and propagation path length, a determination could be made about link performance. The results obtained from the simulation showed that atmospheric turbulence plays a significant role in determining link performance. Originator-Supplied keywords include: Optical Communications, Laser Communications, and Turbulence.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1988 with total page 1020 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Performance Analysis for Near-field Atmospheric Optical Communications by : Baris Ibrahim Erkmen
Download or read book Performance Analysis for Near-field Atmospheric Optical Communications written by Baris Ibrahim Erkmen and published by . This book was released on 2003 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Establishing, high data rate communication links over short distances via fiber-optic cables may prove costly and time consuming, particularly in urban areas. Through-the-air optical communication systems are a reliable and cost effective alternative for establishing high data rate links when the two terminals have a clear line-of-sight. Bad weather conditions, such as rain, snow or fog, degrade performance severely for such links. However, even in clear weather conditions, local refractive index fluctuations in the atmosphere known as atmospheric turbulence, may drastically impair performance. Most optical links are set up to operate in the far-field power transfer regime, in which diffraction spread is the dominant effect on the beam. Therefore, a very small portion of the beam is captured at the receiver, resulting in very weak power coupling between the transmitter and the receiver. However, it is also possible to establish geometries such that the link operates in the near-field regime, where, in absence of turbulence, it is possible to focus the beam onto the receiver with almost perfect power coupling. Work on performance of near-field atmospheric optical communication systems is scarce in existing literature, perhaps due to increased complexity in prescribed models. In this thesis, we analyze error probabilities of binary optical communication links operating in the near-field regime, utilizing on-off keying (OOK) or pulse position modulation (PPM) signaling techniques. We also obtain bounds on the capacity of a single-input, single-output (SISO) atmospheric optical communication link with a coherent-detection receiver operating in the near field.
Book Synopsis Free-Space Optical Communication Systems in Turbulent Channels by : Mohammed Abaza, R.
Download or read book Free-Space Optical Communication Systems in Turbulent Channels written by Mohammed Abaza, R. and published by LAP Lambert Academic Publishing. This book was released on 2012-05 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: The atmospheric turbulence effect on free-space optical (FSO) communications is one of the biggest problems that face FSO systems. Atmospheric turbulence is the fluctuations of the signal due to the changing of refractive index which results from those air particles which are not homogonous and are affected by temperature, pressure, altitude and wind. In this book, different proposed modulation and forward error techniques are applied to decrease the severe effect on bit error rates due to atmospheric turbulence. Two channels models of atmospheric turbulence are used: log-normal channel which represents small distances (i.e. less than 100 m) and negative-exponential channel which represents long distances up to several kilometers. The obtained results demonstrated the superior performance of avalanche photodiode over positive-intrinsic-negative (PIN) receivers with the use of concatenated Reed Solomon codes. Further, it is found that, forward error correction upgrades uncoded FSO to gain a working-distance advantage of a few kilometers.
Book Synopsis Atmospheric Compensation Experiments on Free-space Optical Coherent Communication Systems by : Esdras Anzuola Valencia
Download or read book Atmospheric Compensation Experiments on Free-space Optical Coherent Communication Systems written by Esdras Anzuola Valencia and published by . This book was released on 2015 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last years free-space optical communications systems for wireless links have been proposed, studied, and implemented mainly due to the higher bandwidth that this technology is able to provide. Still, radio frequency (RF) systems have been maintained in practical wireless communications systems due to the improvement of the microwave sources and the development of high speed electronics. Nowadays the circumstances are changing as a consequence of the increasing data-rate needed in terrestrial and outer space communications. The shift from RF systems to optical communication systems in the free space applications provide a wide set of advantageous characteristics that are motivating the use of these optical technologies in detriment of the RF systems. One of the key reasons is the advantage of working with optical wavelengths in compare to the RF spectral band. As well as the already mentioned increase in the available bandwidth due to the fact that higher optical frequencies directly mean wider bandwidths, the use of optical frequencies lead to a better performance in terms of the received power: for equal antenna sizes the received signal goes inversely as the square of the wavelength. Of the most interest, recent coherent optical communication systems address modulation and detection techniques for high spectral efficiency and robustness against transmission impairments. Coherent detection is an advanced detection technique for achieving high spectral efficiency and maximizing power or signal-to-noise (SNR) efficiency, as symbol decisions are made using the in-phase and quadrature signals, allowing information to be encoded in all the available degrees of freedom. In this context, the effects of Earth's atmosphere must be taken into account. Turbulenceinduced wavefront distortions affect the transmitted beam responsible for deterioration of the link bit error rate (BER). The use of adaptive optics to mitigate turbulence-induced phase fluctuations in links employing coherent (synchronous) detection is poised to reduce performance penalties enabling a more capable next generation of free-space optical communications. In this work, we describe the implementation of a free space optical coherent communication system using QPSK modulation and heterodyne downconvertion that uses adaptive optics techniques and digital signal processing to mitigate turbulenceinduced phase fluctuations and channel impairments in coherent receivers. A new method for generating atmospheric turbulence based on binary computer generated holography (BCGH) using binary arrays is presented and its performance is evaluated. The feasibility of FSO coherent systems working with adaptive optics is demonstrated and the system performance in terms of the BER is experimentally evaluated under the influence of atmospheric turbulence. The resulting system performance is compared against the theoretical models. The viability of the approach to improve the system efficiency and sensitivity of coherent receivers is experimentally demonstrated.
Download or read book IETE Technical Review written by and published by . This book was released on 1989 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Critical Assessment of Selected Past Research on Optical Turbulence Information in Diverse Microclimates by :
Download or read book A Critical Assessment of Selected Past Research on Optical Turbulence Information in Diverse Microclimates written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the increased use of laser and ground-to-satellite communications the need for reliable optical turbulence information is growing. Optical turbulence information is important because it describes an atmospheric effect that can degrade the performance of electromagnetic systems and sensors, e.g., free-space optical communications and infrared imaging. However, critical analysis of selected past research indicates that there are some areas (i.e., data and models) in which optical turbulence information is lacking. For example, line-of-sight, optical turbulence data coupled with atmospheric models in hilly terrain, coastal areas, and within built-up urban areas are few in number or non-existent. In addition, the bulk of existing atmospheric computer models that are being used to provide estimates of optical turbulence are basically one-dimensional in nature and assume uniform turbulence conditions over large areas. Therefore, current optical turbulence theory and models may be critically deficient and in error for inhomogeneous turbulence conditions, such as those that occur in urban environments or environments with changing topography and energy budgets. This paper summarizes selected past research on optical turbulence and the refractive index structure parameter (C2n) in diverse microclimates in an effort to identify deficiencies in the optical turbulence information database and to recommend improvements. The database presented here contains optical turbulence (C2n) information at different wavelengths and for different microclinate environments, e.g., in rural, hilly, desert, mountain-valley, urban, coastal, ocean, and arctic. The database includes several examples of measured and modeled values of C2n in the atmospheric surface and boundary layers.
Book Synopsis The Effects of Atmospheric Turbulence on an Air-to-air Optical Communication Link by : Jay N. Kanavos (CAPT, USAF.)
Download or read book The Effects of Atmospheric Turbulence on an Air-to-air Optical Communication Link written by Jay N. Kanavos (CAPT, USAF.) and published by . This book was released on 1984 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Optical Wireless Communications by : Murat Uysal
Download or read book Optical Wireless Communications written by Murat Uysal and published by Springer. This book was released on 2016-08-25 with total page 639 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on optical wireless communications (OWC), an emerging technology with huge potential for the provision of pervasive and reliable next-generation communications networks. It shows how the development of novel and efficient wireless technologies can contribute to a range of transmission links essential for the heterogeneous networks of the future to support various communications services and traffic patterns with ever-increasing demands for higher data-transfer rates. The book starts with a chapter reviewing the OWC field, which explains different sub-technologies (visible-light, ultraviolet (UV) and infrared (IR) communications) and introduces the spectrum of application areas (indoor, vehicular, terrestrial, underwater, intersatellite, deep space, etc.). This provides readers with the necessary background information to understand the specialist material in the main body of the book, which is in four parts. The first of these deals with propagation modelling and channel characterization of OWC channels at different spectral bands and with different applications. The second starts by providing a unified information-theoretic treatment of OWC and then discusses advanced physical-layer methodologies (including, but not limited to: advanced coding, modulation diversity, cooperation and multi-carrier techniques) and the ultimate limitations imposed by practical constraints. On top of the physical layer come the upper-layer protocols and cross-layer designs that are the subject of the third part of the book. The last part of the book features a chapter-by-chapter assessment of selected OWC applications. Optical Wireless Communications is a valuable reference guide for academic researchers and practitioners concerned with the future development of the world’s communication networks. It succinctly but comprehensively presents the latest advances in the field.
Author :Langford B. White Publisher :SPIE-International Society for Optical Engineering ISBN 13 : Total Pages :256 pages Book Rating :4.3/5 (91 download)
Book Synopsis Noise in Communication by : Langford B. White
Download or read book Noise in Communication written by Langford B. White and published by SPIE-International Society for Optical Engineering. This book was released on 2004 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of SPIE present the original research papers presented at SPIE conferences and other high-quality conferences in the broad-ranging fields of optics and photonics. These books provide prompt access to the latest innovations in research and technology in their respective fields. Proceedings of SPIE are among the most cited references in patent literature.
Book Synopsis Free Space Optical Communication by : Hemani Kaushal
Download or read book Free Space Optical Communication written by Hemani Kaushal and published by Springer. This book was released on 2017-01-06 with total page 233 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an in-depth understanding of free space optical (FSO) communication with a particular emphasis on optical beam propagation through atmospheric turbulence. The book is structured in such a way that it provides a basic framework for the beginners and also gives a concise description from a designer’s perspective. The book provides an exposure to FSO technology, fundamental limitations, design methodologies, system trade-offs, acquisition, tracking and pointing (ATP) techniques and link-feasibility analysis. The contents of this book will be of interest to professionals and researchers alike. The book may also be used as a textbook for engineering coursework and professional training.
Author :North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development Publisher : ISBN 13 : Total Pages :410 pages Book Rating :4.3/5 (243 download)
Book Synopsis AGARD Index of Publications by : North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development
Download or read book AGARD Index of Publications written by North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development and published by . This book was released on 1986 with total page 410 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Sensor and Propagation Panel. Symposium Publisher : ISBN 13 : Total Pages :488 pages Book Rating :4.E/5 ( download)
Book Synopsis Digital Communications Systems by : North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Sensor and Propagation Panel. Symposium
Download or read book Digital Communications Systems written by North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Sensor and Propagation Panel. Symposium and published by . This book was released on 1996 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The BRITS Index: Title index by : British Theses Service
Download or read book The BRITS Index: Title index written by British Theses Service and published by . This book was released on 1989 with total page 1158 pages. Available in PDF, EPUB and Kindle. Book excerpt:
