Free-space-optical communications over turbulent channels. (c2009)

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dc.contributor.author Bkassiny, Mario
dc.date.accessioned 2010-12-20T08:42:06Z
dc.date.available 2010-12-20T08:42:06Z
dc.date.copyright 2009 en_US
dc.date.issued 2010-12-20
dc.date.submitted 2009-06-26
dc.identifier.uri http://hdl.handle.net/10725/162
dc.description Includes bibliographical references (leave 91). en_US
dc.description.abstract Local Area Networks (LAN’s) are being expanded over large geographic areas and they are used in many business fields. Thus, communication links between buildings are to be optimized in order to achieve high transmission rates, high performance levels, low cost and ease of deployment. Free-Space Optics (FSO) is a communication system that achieves all of the above objectives and, thus, constitutes a strong candidate solution for such networks. FSO systems are based on transmitting information through light beams in free atmosphere and they suffer from fading due to atmospheric scintillations. Fading effects can be reduced by deploying laser arrays and photo-detector arrays at the transmitter and receiver sides respectively. Such systems are referred to as Multiple-Input-Multiple- Output (MIMO) FSO systems. In addition to their robustness against fading, MIMO FSO systems can also enhance the data rate since the array of lasers can be driven by independent information sources. Fading over FSO channels is often modeled by either Log-Normal or Rayleigh distributions. In this context, the first contribution of this work consists of an analytical characterization of the diversity order that can be achieved by MIMO FSO systems over such channels. Based on the Erlang approximation, closed-form expressions of the error-rate and channel-capacity were derived. These simple expressions offer useful insights on the performance gains that can be achieved at a given Signal-to-Noise Ratio (SNR). On the other hand, for estimating the values of the transmitted signals, exiting MIMO FSO systems are often associated with Maximum-Likelihood (ML) decoders. Although these decoders achieve the smallest error rate, they suffer from an increased complexity since the required decoding time increases exponentially with the size of the transmitted constellation. The second contribution of this work consists of proposing two novel simplified ML decoders that reduce the processing time without increasing the error rate. We also propose suboptimal versions of these decoders that present the advantage of very fast convergence times at the expense of a slight increase in the error rate. All the presented analysis and designs are supported by simulations and analytical proofs. en_US
dc.language.iso en en_US
dc.subject Optical communications en_US
dc.title Free-space-optical communications over turbulent channels. (c2009) en_US
dc.type Thesis en_US
dc.title.subtitle performance analysis and transceiver design with optimal and suboptimal decoding en_US
dc.term.submitted Spring en_US
dc.author.school Engineering en_US
dc.author.idnumber 200301360 en_US
dc.author.commembers Samer Saab en_US
dc.author.commembers Wissam Fawaz en_US
dc.author.woa OA en_US
dc.author.department MSE in Computer Engineering en_US
dc.description.physdesc 1 bound copy: ix, 91 leaves; col. ill.; 31 cm. available at RNL. en_US
dc.author.division Computer Engineering en_US
dc.author.advisor Chadi Abou Rjeily en_US
dc.identifier.doi https://doi.org/10.26756/th.2009.5 en_US

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