Results 151 to 160 of about 2,223,777 (199)
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To Spread or Not to Spread – the Myths of Optical CDMA
Optical Fiber Communication Conference and International Conference on Quantum Information, 2001In a spread spectrum system, the signal is transmitted using a bandwidth much larger than that required for the transmitted data. By spreading the signal energy over a very broad bandwidth, one can obtain a multitude of benefits. Firstly, one can make the signal difficult to detect by lowering its spectral density and hiding it under noise.
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Performance comparison of multiwavelength CDMA and WDMA+CDMA for fiber-optic networks
IEEE Transactions on Communications, 1997A "multiwavelength" scheme has been proposed to support large numbers of subscribers and simultaneous users in optical code-division multiple-access (CDMA) networks without using very large bandwidth expansion or the need of complicated and not-yet-feasible optical processing.
Guu-Chang Yang, Wing C. Kwong
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Optical CDMA Detection by Orthogonal Matching Pursuit
Proceedings. (ICASSP '05). IEEE International Conference on Acoustics, Speech, and Signal Processing, 2005., 2006In this paper, we present a novel optical CDMA multi-user detector employing the orthogonal matching pursuit algorithm. The proposed system is compared with most of the receiver structures in the literature. It is shown by simulation results that the proposed detection architecture is a very promising candidate with its low computational complexity ...
Tolga Kurt +2 more
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Sequences for Phase-Encoded Optical CDMA
2007In phase-encoded optical CDMA (OCDMA) spreading is achieved by encoding the phase of signal spectrum. Here, a mathematical model for the output signal of a phase-encoded OCDMA system is first derived. This is shown to lead to a performance metric for the design of spreading sequences for asynchronous transmission. Generalized bent functions are used
Reza Omrani +2 more
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Optical fibre CDMA for access and optical networks
2007 6th International Conference on Information, Communications & Signal Processing, 2007A new design technique for circuits capable of encoding and decoding 40 GChip/s CDMA signals is proposed. We report the concept and circuit design of two novel structures, based on the distributed amplifier/filter topology, to operate at speeds close to the cut-off frequency of the transistors employed.
Miguel N. Pimenta, Izzat Darwazeh
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On the Combination of Optical CDMA and POLSK
Journal of Optical Communications, 1995The present paper describes the advantages of the combination of optical Code Division Multiple Access (CDMA) and Polarization Shift Keying (POLSK). By means of a derived new receiver model it is shown that the normally disturbing statistical fluctuations of the State of Polarization (SOP) on a single-mode optical fiber result in an attenuation of the ...
K. Iversen, D. Junghanns
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Optical CDMA for a constellation of CubeSats
2018 IEEE Aerospace Conference, 2018In this paper, an end-to-end optical CubeSat Code Division Multiple Access (CDMA) system architecture is developed. The signal processing components required for successful operation are defined. Performance analysis for the uncoded case for N CubeSats is derived.
Dariush Divsalar +5 more
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Proceedings of GLOBECOM'96. 1996 IEEE Global Telecommunications Conference, 2002
In this paper a basic theory of optical code division multiple access (CDMA) is presented. Based on the nonlinear detection principle of photodiodes and the coherence time of optical sources a general receiver model is deduced. From this model nine elementary structures can be found, enabling the theoretical analysis of all known schemes.
K. Iversen, J. Muckenheim, D. Nampicke
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In this paper a basic theory of optical code division multiple access (CDMA) is presented. Based on the nonlinear detection principle of photodiodes and the coherence time of optical sources a general receiver model is deduced. From this model nine elementary structures can be found, enabling the theoretical analysis of all known schemes.
K. Iversen, J. Muckenheim, D. Nampicke
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Optical CDMA with interference cancellation
Proceedings of ISSSTA'95 International Symposium on Spread Spectrum Techniques and Applications, 2002A multiple-user interference reduction technique is proposed for optical code-division multiple-access systems. Data symbols from each user are encoded using pulse-position modulation scheme before multiplexing. Modified prime sequences are adopted as the signature codes in the multiplexing process.
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Optical CDMA System Using Bacteriorhodopsin for Optical Data Storage
Biotechnology Progress, 1999An optical CDMA (code division multiple access) system for the optical data storage using bacteriorhodopsin (BR) is reported as an application of the BR materials. The desired signal of multiple input can be recorded and reconstructed by use of orthogonal codes. An experimental setup is proposed and demonstrated.
Bae, YS +4 more
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