Performance analysis of FSO cooperative communications with rf inter-connected relays in the absence and presence of channel state information. (c2018)

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dc.contributor.author Hamad, Mustapha Ismail
dc.date.accessioned 2018-10-17T06:48:27Z
dc.date.available 2018-10-17T06:48:27Z
dc.date.copyright 2018 en_US
dc.date.issued 2018-10-17
dc.date.submitted 2018-07-18
dc.identifier.uri http://hdl.handle.net/10725/8649
dc.description.abstract Free Space Optics (FSO) communication systems have been heavily studied in the literature during the recent decade. Compared to the widely used and traditional Radio Frequency (RF) communication systems, FSO systems are believed to achieve much higher data rates and better performance in terms of feasibility and practicality to compile with the worldwide increased speed need and uprising fast technologies. However, as the case for any new technology, various limitations and challenges such as bad weather conditions, atmospheric turbulence, scintillation, and building sways, face FSO technology. As a result, continuous research is being conducted in the field to overcome these challenges and enhance the system reliability and performance. Among the explored solutions, deploying cooperative schemes in the context of the FSO communication systems was proven to add another degree of freedom for the existent systems. More specifically, diversity methods and inter-relay cooperative schemes are the leading between the discussed techniques as they suggest exploiting the existing relays in the system without any extra needed hardware or resources. Parallel relaying without inter-relay cooperation (NIRC), unidirectional inter-relay cooperation (IRC1), and bidirectional inter-relay cooperation (IRC2) are three main categories that have been studied recently which exploit the existence of adjacent relays in the system to cooperate in the communication process. NIRC schemes use two types of FSO links in the communication system: source to relay S􀀀R and relay to destination R􀀀D links, while IRC schemes benefit additionally from the existence of inter-relay R􀀀R links connecting each pair of adjacent relays. However, none of the done work in the field tackles the possibility of talking advantage of another potential inter-relay links other than those connecting adjacent pairs. Therefore, the work in this thesis proposes a novel method which deploys a full inter-relay connectivity scheme labeled as Allto- All relaying scheme. Conversely, some limitations face the proposed scheme such as the difficulty of ensuring clear line of sight (LOS) between all the relays in the system which is required for deploying the FSO links. Moreover, the RF links still offer higher reliability in bad weather conditions and at the same time are of broadcasting nature which is more practical for the proposed All-to-All scheme. Moreover, RF links are used as backup for the FSO links of practical FSO systems which exist in the market today. Therefore, we propose in this thesis a novel mixed RF/FSO All-to-All connected system which combines the advantages of both FSO and RF technologies. The proposed system ensures the high data rates empowered by the FSO links deployed for S􀀀R, R􀀀D, and S􀀀D links. Moreover it maintains high reliability by activating the R􀀀R RF links whenever needed in the communication process. In fact, the proposed system is encouraging as it does not require any extra hardware or resources. In this thesis, we describe the proposed system components, functionalities, requirements, strategies, advantages and the gains carried with it compared to existing systems and relaying schemes. We also present two protocols that the system can work with: (1) All-Active relaying where all the FSO links are activated to participate in the cooperation strategy and (2) Selective relaying where only the strongest path is selected for the communication process. Selective relaying is showed to achieve higher gains compared with All-Active but with the cost of prior knowledge of channel state information (CSI). Therefore, a detailed comparison and analysis are presented in this thesis at two levels: (1) The proposed system vs existing systems and (2) All-Active relaying vs Selective relaying. The conducted analysis is carried out in terms of outage probability analysis and diversity order analysis where the first studies the effects of implementing the proposed system under the different relaying protocols in lowering the outage probability of the system thus increasing its reliability. In addition, the diversity order analysis presents another performance measurement of the system behavior under different relaying schemes and techniques. The results show superiority of the proposed mixed RF/FSO All-to-All scheme over other existing relaying schemes such as NIRC, IRC1, and IRC2, in addition to the superiority of the Selective relaying protocol over the All-Active relaying protocol. The results are studied theoretical in three aspects: exact, approximate, and simulated analysis, and supported by experimental modeling with numerical results which validate the theoretical analysis. The flow of work in this thesis is given as follows: Chapter one presents a review of the communication technologies with special highlights on the FSO generalities and the implemented diversity methods. Then, chapter two explains the mathematical tools and concepts such as conditional probability approach, minimum cut set method, and Monte Carlo simulation that are used throughout the whole thesis. Moreover, the system model along with all used channel models and corresponding equations are presented in chapter three. The core of the thesis is presented in chapters four and five where a detailed outage probability analysis and diversity order analysis are presented, respectively. The presented analysis in both chapters covers both special cases and general cases for any number of relays under both relaying protocols: All- Active and Selective. A proper comparison is conducted between the relevant schemes under different network setups and correspondingly valid conclusions are derived theoretically and then verified numerically in chapter six. Finally, the presented work is summarized and potential future work is suggested at the end of this thesis in chapter seven. en_US
dc.language.iso en en_US
dc.subject Lebanese American University -- Dissertations en_US
dc.subject Dissertations, Academic en_US
dc.subject Free space optical interconnects en_US
dc.subject Optical communications en_US
dc.title Performance analysis of FSO cooperative communications with rf inter-connected relays in the absence and presence of channel state information. (c2018) en_US
dc.type Thesis en_US
dc.term.submitted Summer en_US
dc.author.degree MSE in Computer Engineering en_US
dc.author.school SOE en_US
dc.author.idnumber 201102654 en_US
dc.author.commembers Fawaz, Wissam en_US
dc.author.commembers Ghajar, Raymond en_US
dc.author.department Electrical And Computer Engineering en_US
dc.description.embargo N/A en_US
dc.description.physdesc 1 hard copy: xx, 178 leaves; col. ill.; 30 cm. available at RNL. en_US
dc.author.advisor Abou Rjeily, Chadi en_US
dc.keywords Free Space Optics en_US
dc.keywords FSO en_US
dc.keywords Radio Frequency en_US
dc.keywords RF en_US
dc.keywords Communication en_US
dc.keywords Cooperation en_US
dc.keywords Cocooperative schemes en_US
dc.keywords Diversity en_US
dc.keywords Relaying en_US
dc.keywords Parallel relaying en_US
dc.keywords Inter relay en_US
dc.keywords Serial relaying en_US
dc.keywords Outage en_US
dc.keywords Probability en_US
dc.keywords NIRC en_US
dc.keywords IRC1 en_US
dc.keywords IRC2 en_US
dc.keywords All-to-All en_US
dc.keywords All-Active relaying en_US
dc.keywords Selective relaying en_US
dc.keywords CSI en_US
dc.keywords Diversity order en_US
dc.keywords Gamma-Gamma en_US
dc.keywords Rician en_US
dc.keywords Rayleigh en_US
dc.keywords Minimum cut set en_US
dc.keywords Monte Carlo en_US
dc.keywords Atmospheric turbulence en_US
dc.keywords Scintillation en_US
dc.description.bibliographiccitations Bibliography : leaves 157-170. en_US
dc.identifier.doi https://doi.org/10.26756/th.2018.100 en_US
dc.author.email mustapha.hamad@lau.edu.lb en_US
dc.identifier.tou http://libraries.lau.edu.lb/research/laur/terms-of-use/thesis.php en_US
dc.publisher.institution Lebanese American University en_US
dc.author.affiliation Lebanese American University en_US

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