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Proceedings ArticleDOI: 10.1109/ICAEE.2014.6838435

Cooperative Wireless Optical communication system using IWO based optimal relay placement

19 Jun 2014-pp 1-6
Abstract: Wireless Optical communication [WOC] is improved using relay assisted transmission which exploits multiple shorter hops that gives a better performance gain. Relay assisted transmission is used as a mitigation tool in combating atmospheric turbulence occurring in the communication channels. The prime aim is to minimize the outage probability and optimize relay locations for parallel and serial FSO relaying. In this paper we aim to address the major limiting factor for links measuring more than a kilometer; the error rate performances is dismal and therefore relay assisted transmission is employed to combat this shortcoming. The main focus of this study is on considering the channel model, in which turbulence-induced fading and path-loss are considered. The locations of the relay are evaluated using different algorithms and then compared to find out the best optimized result obtained from the simulation results. more

Topics: Relay channel (71%), Relay (58%), Fading (52%) more

Book ChapterDOI: 10.1007/978-3-030-32523-7_56
Ibrahima Gueye1, Ibra Dioum1, K. Wane Keita1, Idy Diop1  +3 moreInstitutions (1)
24 Oct 2019-
Abstract: This paper proposes the use of the technique of cooperative systems in wireless optical communication. Several obstacles can degrade the performance of information transmission in wireless optical links. These include atmospheric turbulence in communication links greater than 1 km, the rocking of buildings, wireless optical channel fading and flickering. Several studies have shown that the use of cooperative systems in this communication technique has better performance compared to conventional systems. To improve the performance of the transmission in the optical links we propose to place a DF (Decode and Forward) relay between the transmitter and the receiver, using the LDPC (Low-density Parity-check) codes at the relay level. Another innovation of this article is the introduction of the series relays to connect two very distant sites by also using LDPC at the level of each relay. Our method achieves a remarkable efficiency in terms of BER (Bit Error Rate) compared to some previous work. more

Topics: Low-density parity-check code (57%), Relay (56%), Wireless (56%) more

1 Citations


Journal ArticleDOI: 10.1109/TIT.2004.838089
J.N. Laneman1, David Tse2, Gregory W. Wornell1Institutions (2)
Abstract: We develop and analyze low-complexity cooperative diversity protocols that combat fading induced by multipath propagation in wireless networks. The underlying techniques exploit space diversity available through cooperating terminals' relaying signals for one another. We outline several strategies employed by the cooperating radios, including fixed relaying schemes such as amplify-and-forward and decode-and-forward, selection relaying schemes that adapt based upon channel measurements between the cooperating terminals, and incremental relaying schemes that adapt based upon limited feedback from the destination terminal. We develop performance characterizations in terms of outage events and associated outage probabilities, which measure robustness of the transmissions to fading, focusing on the high signal-to-noise ratio (SNR) regime. Except for fixed decode-and-forward, all of our cooperative diversity protocols are efficient in the sense that they achieve full diversity (i.e., second-order diversity in the case of two terminals), and, moreover, are close to optimum (within 1.5 dB) in certain regimes. Thus, using distributed antennas, we can provide the powerful benefits of space diversity without need for physical arrays, though at a loss of spectral efficiency due to half-duplex operation and possibly at the cost of additional receive hardware. Applicable to any wireless setting, including cellular or ad hoc networks-wherever space constraints preclude the use of physical arrays-the performance characterizations reveal that large power or energy savings result from the use of these protocols. more

Topics: Cooperative diversity (68%), Antenna diversity (63%), Fading (59%) more

12,519 Citations

Journal ArticleDOI: 10.1109/TCOMM.2003.818096
Abstract: Mobile users' data rate and quality of service are limited by the fact that, within the duration of any given call, they experience severe variations in signal attenuation, thereby necessitating the use of some type of diversity. In this two-part paper, we propose a new form of spatial diversity, in which diversity gains are achieved via the cooperation of mobile users. Part I describes the user cooperation strategy, while Part II (see ibid., p.1939-48) focuses on implementation issues and performance analysis. Results show that, even though the interuser channel is noisy, cooperation leads not only to an increase in capacity for both users but also to a more robust system, where users' achievable rates are less susceptible to channel variations. more

6,572 Citations

Open accessBook
05 Jan 1998-
Abstract: Introduction to Optimization The Binary Genetic Algorithm The Continuous Parameter Genetic Algorithm Applications An Added Level of Sophistication Advanced Applications Evolutionary Trends Appendix Glossary Index. more

Topics: Genetic algorithm (59%)

3,945 Citations

Journal ArticleDOI: 10.1109/TCOMM.2003.819238
Abstract: For pt.I see ibid., p.1927-38. This is the second of a two-part paper on a new form of spatial diversity, where diversity gains are achieved through the cooperation of mobile users. Part I described the user cooperation concept and proposed a cooperation strategy for a conventional code-division multiple-access (CDMA) system. Part II investigates the cooperation concept further and considers practical issues related to its implementation. In particular, we investigate the optimal and suboptimal receiver design, and present performance analysis for the conventional CDMA implementation proposed in Part I. We also consider a high-rate CDMA implementation and a cooperation strategy when assumptions about the channel state information at the transmitters are relaxed. We illustrate that, under all scenarios studied, cooperation is beneficial in terms of increasing system throughput and cell coverage, as well as decreasing sensitivity to channel variations. more

3,255 Citations

Open access
Christopher R. Houck1Institutions (1)
01 Jan 2001-
Abstract: A genetic algorithm implemented in Matlab is presented. Matlab is used for the following reasons: it provides many built in auxiliary functions useful for function optimization; it is completely portable; and it is e cient for numerical computations. The genetic algorithm toolbox developed is tested on a series of non-linear, multi-modal, non-convex test problems and compared with results using simulated annealing. The genetic algorithm using a oat representation is found to be superior to both a binary genetic algorithm and simulated annealing in terms of e ciency and quality of solution. The use of genetic algorithm toolbox as well as the code is introduced in the paper. more

Topics: Meta-optimization (68%), Simulated annealing (58%), Genetic algorithm (58%) more

1,274 Citations

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