46 research outputs found

    Analog Network Coding for Multi-User Spread-Spectrum Communication Systems

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    This work presents another look at an analog network coding scheme for multi-user spread-spectrum communication systems. Our proposed system combines coding and cooperation between a relay and users to boost the throughput and to exploit interference. To this end, each pair of users, A\mathcal{A} and B\mathcal{B}, that communicate with each other via a relay R\mathcal{R} shares the same spreading code. The relay has two roles, it synchronizes network transmissions and it broadcasts the combined signals received from users. From user B\mathcal{B}'s point of view, the signal is decoded, and then, the data transmitted by user A\mathcal{A} is recovered by subtracting user B\mathcal{B}'s own data. We derive the analytical performance of this system for an additive white Gaussian noise channel with the presence of multi-user interference, and we confirm its accuracy by simulation.Comment: 6 pages, 2 figures, to appear at IEEE WCNC'1

    Chaos-Based Communication Systems

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    The attractive properties of chaos signal that is generated from dynamic systems motivate the researchers to explore the advantage of using this signal type as a carrier in different communication systems. In this chapter, different types of digital chaos–based communication system are discussed; in particular, digital communications where reference signal and its modulated version are transmitted together. This type is called differential coherent systems. Brief surveys on the recently developed systems are presented

    Analysis of bit error rates for multiple access CSK and DCSK communication systems

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    Author name used in this publication: W. M. TamAuthor name used in this publication: Francis C. M. LauAuthor name used in this publication: Chi K. Tse2002-2003 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Coexistence of chaos-based and conventional digital communication systems of equal bit rate

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    Author name used in this publication: Francis C. M. LauAuthor name used in this publication: Chi K. TseAuthor name used in this publication: Sau F. Hau2003-2004 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    PERFORMANCE ANALYSIS OF QUADRATURE CHAOS SHIFT

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    One of the most famous techniques of non-coherent differential chaos shift keying (DCSK) is Quadrature chaos shift keying (QCSK) system, this system suffered from lowering the data rate and increasing the bit energy during the bit transmission even though its rate doubling the one of the DCSK. Short reference (SR) algorithm is proposed for the QCSK system to design the SR-QCSK communication system that enhances these drawbacks. The main idea of the short reference technique is minimizing the length of the reference chaotic signal (β) at a transmitter by a factor P comparing to produce R samples for the new reference signal while the length of the information-bearing signal remained unchanged, this occurs by duplicating the reference signal P times to get the same length as the conventional QCSK. Therefore, the symbol duration is reduced from 2βTc to (R+β)Tc. The data rate and energy saving improvement factor in a percent form is derived and compared with the QCSK and DCSK systems. Also, the BER analytical expression is derived for the SR-QCSK in additive white Gaussian noise and Rayleigh fading channel. The experimental simulation results proved that the theory derivation gives a good analysis tracking for the BER performance. The SR-QCSK system is compared with other DCSK techniques and the simulation results show that it has a superior performance in the multipath Rayleigh fading channel

    Chaos-based underwater communication with arbitrary transducers and bandwidth

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    Acknowledgments: This research is supported in part by National Natural Science Foundation of China (61172070), Innovative Research Team of Shaanxi Province (2013KCT-04), The Key Basic Research Fund of Shaanxi Province (2016ZDJC-01), EPSRC (EP/I032606/1), Chao Bai was supported by Excellent Ph.D. research fund (310-252071603) at XAUT.Peer reviewedPublisher PD

    Double-Stream Differential Chaos Shift Keying Communications Exploiting Chaotic Shape Forming Filter and Sequence Mapping

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    ACKNOWLEDGMENT This research have been supported in part by the Scientific and Technological Innovation Leading Talents Program of Shaanxi Province, China Postdoctoral Science Foundation Funded Project (2020M673349), Open Research Fund from Shaanxi Key Laboratory of Complex System Control and Intelligent Information Processing (2020CP02)Peer reviewedPostprin

    Generalized correlation-delay-shift-keying scheme for noncoherent chaos-based communication systems

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