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Circuits and Systems I: Fundamental Theory and Applications, IEEE Transactions on

Issue 12 • Date Dec. 2000

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Displaying Results 1 - 12 of 12
  • Theoretical noise performance of correlator-based chaotic communications schemes

    Publication Year: 2000 , Page(s): 1692 - 1701
    Cited by:  Papers (42)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (145 KB)  

    In wireless local area networks and indoor communications, multipath propagation limits the performance of data communications systems. To overcome the multipath propagation problem, a spread spectrum system has to be used. The chaotic communications technique, where inherently wideband chaotic basis functions are used, offers a cheap alternative to conventional spread spectrum communications. Unfortunately, analytic expressions for the noise performance of chaotic modulation schemes are not available in the literature. This has so far prevented a full exploitation of the features of chaotic modulation schemes. By generalizing the waveform communications concept, this paper develops exact expressions for the noise performance of the coherent antipodal chaos shift keying (CSK), coherent differential chaos shift keying (DCSK), and differentially coherent DCSK modulation schemes. We show that the properties of the basis functions have no effect on the noise performance of a modulation scheme, provided that the energy per bit is constant. In this sense, the concept of waveform communications is generalized. Finally, our theoretical results are verified by computer simulations. View full abstract»

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  • List of reviewers

    Publication Year: 2000 , Page(s): 1733 - 1737
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    Freely Available from IEEE
  • Author index

    Publication Year: 2000 , Page(s): 1738 - 1744
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    Freely Available from IEEE
  • Subject index

    Publication Year: 2000 , Page(s): 1744 - 1764
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    Freely Available from IEEE
  • Stochastic-calculus-based numerical evaluation and performance analysis of chaotic communication systems

    Publication Year: 2000 , Page(s): 1663 - 1672
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (224 KB)  

    Performance evaluation of a self-synchronizing Lorenz chaotic system is formulated as a stochastic differential equation problem. Based on stochastic calculus, we provide a rigorous formulation of the numerical evaluation and analysis of the self-synchronization capability and error probabilities of two chaotic Lorenz communication systems with additive white Gaussian noise disturbance. By using the Ito theorem, we are able to analyze the first two moments behavior of the self-synchronization error of a drive-response Lorenz chaotic system. The moment stability condition of the synchronization error dynamic is explicitly derived. These results provide further understanding on the robust self-synchronization ability of the Lorenz system to noise. Various time-scaling factors affecting the speed of system evolution are also discussed. Moreover, an approximate model of the variance of the sufficient statistic of the chaotic communication is derived, which permits a comparison of the chaotic communication system performance to the conventional binary pulse amplitude modulation communication system. Due to synchronization difficulties of chaotic systems, known synchronization-based chaotic communication system performance is quite poor. Thus, alternative synchronization-free chaotic communication systems are needed in the future, The use of a stochastic calculus approach as considered here, however, is still applicable if the considered chaotic communication system is governed by nonlinear stochastic differential equations View full abstract»

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  • Performance evaluation of FM-DCSK modulation in multipath environments

    Publication Year: 2000 , Page(s): 1702 - 1711
    Cited by:  Papers (36)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (196 KB)  

    G. Kolumban [2000] has shown that, under specified conditions, the noise performance of frequency-modulated differential chaos shift keying (FM-DCSK) in a single-ray additive white Gaussian noise channel is independent of the shape of the underlying waveform. This paper discusses the qualitative features of the FM-DCSK system and characterizes the performance of this system in standard reference multipath channels View full abstract»

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  • Application of noise reduction to chaotic communications: a case study

    Publication Year: 2000 , Page(s): 1720 - 1725
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (160 KB)  

    Over the past few years, several methods have been proposed for decontaminating noisy chaotic signals by exploiting the short-term predictability of chaotic signals. This work evaluates the effectiveness, for a differential chaos shift keying (DCSK) telecommunications system, of a noise reduction approach using a deterministic optimization technique. Noise reduction is governed by a cost function which consists of two terms: the first gives the distance between the noisy and enhanced orbits, while the second one checks the dynamics of the cleaned signal. These two terms are weighted by a scalar Γ. The effect of this factor on the noise reduction performance is also studied. Evaluation of the noise performance of a telecommunication system by computer simulation requires a very long simulation time. We propose a computationally-efficient criterion for quantifying the performance improvement of a DCSK system. We show that the noise reduction technique improves the overall noise performance only if the energy per bit-to-noise spectral density (Eb/N0) exceeds a certain threshold. The effect of code length on this threshold level is also evaluated. Finally, the effect of parameter mismatch, which is present in every practical system, is analyzed View full abstract»

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  • Optimal detection of differential chaos shift keying

    Publication Year: 2000 , Page(s): 1712 - 1719
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB)  

    Recent advances in the development of communication schemes based on chaos suggest that differential chaos shift keying (DCSK) is one of the most promising candidates for a feasible implementation. Traditionally, the demodulation-decoding of DCSK has been achieved by means of a noncoherent approach based on a correlation detector This approach in general works fur any differential noise shift keying out of which DCSK is a subclass, i.e., it does not exploit the chaotic dynamics involved. In this paper it is shown that the simple correlation detector can be augmented by information based on the chaotic dynamics to improve the performance, yielding a statistically optimal detection. Introducing a rigorous probabilistic framework, the optimal receiver for additive white Gaussian noise is derived, and it is shown that it decomposes into a part based an correlation and a part based on the chaotic dynamics View full abstract»

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  • Performance analysis of correlation-based communication schemes utilizing chaos

    Publication Year: 2000 , Page(s): 1684 - 1691
    Cited by:  Papers (66)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (296 KB)  

    Using chaotic signals in spread-spectrum communications has a few clear advantages over traditional approaches. Chaotic signals are nonperiodic, wideband, and more difficult to predict, reconstruct, and characterize than periodic carriers. These properties of chaotic signals make it more difficult to intercept and decode the information modulated upon them. However, many suggested chaos-based communication schemes do not provide processing gain, a feature highly desirable in spread-spectrum communication schemes. In this paper, we suggest two communication schemes that provide a processing gain. The performance of these and of the earlier proposed differential chaos shift keying is studied analytically and numerically for discrete time implementations. It is shown that, when performance is characterized by the dependence of bit error rate on Eb/N0, the increase of the spreading sequence length beyond a certain point degrades the performance. For a given Eb/N0, there is a length of the spreading sequence that minimizes the bit error rate View full abstract»

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  • Communications using chaos≫MINUS. III. Performance bounds for correlation receivers

    Publication Year: 2000 , Page(s): 1673 - 1683
    Cited by:  Papers (41)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB)  

    For pt. II, see ibid., vol. 45, p. 1129-40 (1998). In a digital communications system, data is transmitted from one location to another by mapping bit sequences to symbols, and symbols to sample functions of analog waveforms. The analog waveform passes through a bandlimited (possibly time-varying) analog channel, where the signal is distorted and noise is added. In a typical conventional system, the analog sample functions sent through the channel are weighted sums of one or more sinusoids, called basis functions; in a chaotic communications system, the sample functions are segments of chaotic waveforms. This three-part paper shows in a tutorial manner how the theory of conventional telecommunications systems can be applied to chaotic modulation schemes. In addition, it discusses the latest results in the field of chaotic communications. In Part III, examples are given of chaotic communications schemes with and without synchronization, and the performance of correlator-based systems is evaluated in the context of noisy, bandlimited channels View full abstract»

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  • Special issue on "noncoherent chaotic communications"

    Publication Year: 2000 , Page(s): 1661 - 1662
    Cited by:  Papers (3)
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    First Page of the Article
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  • Noise performance of chaotic communication systems

    Publication Year: 2000 , Page(s): 1726 - 1732
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (244 KB)  

    We present cumulant analysis tools suitable fur the study of chaos communication systems. The approach uses random process models for all signals involved. The analysis is applied to the differential chaos shift keying (DCSK) scheme and its close relative-the transmitted reference (TR) approach under additive white Gaussian noise channel conditions. Approximative as well as exact performance figures are derived, the latter agreeing with results recently presented in the literature. The parameter ranges for the application of either solution are specified. The noise robustness problem present in DCSK/TR is discussed and quantified View full abstract»

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