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

Issue 12 • Date Dec. 2001

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Displaying Results 1 - 19 of 19
  • Introduction to the special issue

    Publication Year: 2001 , Page(s): 1385 - 1388
    Cited by:  Papers (13)
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  • List of reviewers

    Publication Year: 2001 , Page(s): 1389 - 1393
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  • Chaotic communications over radio channels

    Publication Year: 2001 , Page(s): 1394 - 1404
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (358 KB) |  | HTML iconHTML  

    The real issues of communicating over radio channels with continuous time chaotic signals are addressed. Synchronized and nonsynchronized methods are assessed. The modeling of radio channels (including multipath and Doppler) is reviewed, and then the effect on chaotic signals is investigated. The bandwidth efficiency of chaotic communication systems is discussed, and compared to conventional metho... View full abstract»

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  • Generalized frequency modulation

    Publication Year: 2001 , Page(s): 1405 - 1412
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (213 KB) |  | HTML iconHTML  

    A generalization of frequency modulation is developed in which state trajectories of dynamical systems are used as carrier waves. Our focus is on the design and analysis of modulators and demodulators for such generalized frequency modulation systems. In particular, we show that for a class of dynamical systems, among which are certain chaotic systems, it is possible to develop a general approach ... View full abstract»

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  • Stability of inverse-system approaches in coherent chaotic communication

    Publication Year: 2001 , Page(s): 1413 - 1423
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (288 KB) |  | HTML iconHTML  

    The stability of inverse-system approaches for communications using chaotic signals is studied in this paper. In this approach, the transmitter contains a chaotic oscillator with an input that is modulated by the information signal. The receiver is an approximation of the exact inverse-dynamics where the time-derivative of the transmitted signal is approximated as the output of a linear filter. Su... View full abstract»

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  • Pseudo-chaotic time hopping for UWB impulse radio

    Publication Year: 2001 , Page(s): 1424 - 1435
    Cited by:  Papers (58)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (243 KB) |  | HTML iconHTML  

    In this paper, we propose a pseudo-chaotic modulation suitable for ultrawide-bandwidth impulse-radio communication systems. The coding scheme is based upon controlling the symbolic dynamics of a chaotic map for encoding the digital information to be transmitted. The pseudo-chaotic time hopping enhances the spread-spectrum characteristics of the system, by removing most periodic components from the... View full abstract»

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  • Digital communication using chaotic-pulse-position modulation

    Publication Year: 2001 , Page(s): 1436 - 1444
    Cited by:  Papers (28)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (319 KB) |  | HTML iconHTML  

    Utilization of chaotic signals for covert communications remains a very promising practical application. Multiple studies indicate that the major shortcoming of recently proposed chaos-based communication schemes is their susceptibility to noise and distortions in communication channels. In this paper, we review a new approach to communication with chaotic signals, which demonstrates good performa... View full abstract»

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  • Chaos-based asynchronous DS-CDMA systems and enhanced Rake receivers: measuring the improvements

    Publication Year: 2001 , Page(s): 1445 - 1453
    Cited by:  Papers (22)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (206 KB) |  | HTML iconHTML  

    Results of recent theoretical investigations highlighted that the use of chaos in direct-sequence code-division multiple access (DS-CDMA) systems may lead to nonnegligible improvements in communication quality for several scenarios. We here briefly review the main steps in this derivation and report the experimental verifications of the corresponding theoretical prediction. With this, we confirm t... View full abstract»

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  • Noise reduction for human speech signals by local projections in embedding spaces

    Publication Year: 2001 , Page(s): 1454 - 1461
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (164 KB) |  | HTML iconHTML  

    A local projective noise-reduction scheme, originally developed for low-dimensional deterministic stationary signals, is successfully applied to human speech. This is possible by exploiting properties of the speech signal which mimic structure exhibited by deterministic chaotic systems. In high-dimensional embedding spaces, the strong nonstationarity is resolved as a sequence of different dynamica... View full abstract»

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  • Mixed-signal map-configurable integrated chaos generator for chaotic communications

    Publication Year: 2001 , Page(s): 1462 - 1474
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (661 KB) |  | HTML iconHTML  

    This paper proposes a mixed-signal map-configurable chaos generator suitable for silicon integration, and makes an exhaustive analysis of its error sources and tolerance to the onset of saturation. The developed methodology has been applied in the design, embedded in a complete frequency-modulated differential-chaos shift keying (FM-DCSK) modem, of a chaos generator which achieves 10 bit resolutio... View full abstract»

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  • Optical-communication systems based on chaos in semiconductor lasers

    Publication Year: 2001 , Page(s): 1475 - 1483
    Cited by:  Papers (30)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (223 KB) |  | HTML iconHTML  

    Chaotic optical-communication systems using semiconductor lasers are studied. The dynamics, synchronization, and message encoding and decoding are modeled and studied numerically and experimentally for two systems which are based on optical injection and delayed optoelectronic feedback of semiconductor lasers, respectively. An optically-injected single-mode semiconductor laser is a nonautonomous n... View full abstract»

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  • Communication using synchronization of optical-feedback-induced chaos in semiconductor lasers

    Publication Year: 2001 , Page(s): 1484 - 1490
    Cited by:  Papers (22)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (137 KB) |  | HTML iconHTML  

    A communication system based on the synchronization of optical chaos in semiconductor lasers is proposed. The optical chaos is generated in a single-mode semiconductor laser with external ring optical feedback. Synchronization of chaos is performed by a direct optical-injection scheme that consists of a transmitter laser with an external optical feedback and a receiver laser with optical injection... View full abstract»

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  • Parallel communication with optical spatiotemporal chaos

    Publication Year: 2001 , Page(s): 1491 - 1497
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (254 KB) |  | HTML iconHTML  

    We investigate the potential of chaotic-optical wavefronts as information carriers in parallel communication systems. Numerical simulations show that broad-area nonlinear ring cavities generate spatiotemporally chaotic signals which allow encoding and decoding of data in space and time. The synchronization process on which the scheme is based, along with the efficiency of the communication system,... View full abstract»

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  • Chaos and cryptography

    Publication Year: 2001 , Page(s): 1498 - 1509
    Cited by:  Papers (86)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (235 KB) |  | HTML iconHTML  

    In this paper, the authors present their opinion and research results collected during the last ten years on the conjunction of chaos and cryptography. Special consideration is taken to show some general critical points and limitations of this approach and to provide some pointers to a comprehensive and careful evaluation of the cryptographical properties of chaotic systems. View full abstract»

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  • Quadrature chaos-shift keying: theory and performance analysis

    Publication Year: 2001 , Page(s): 1510 - 1519
    Cited by:  Papers (34)  |  Patents (27)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (370 KB) |  | HTML iconHTML  

    In this brief, we propose a multilevel version of the differential chaos shift keying (DCSK) telecommunication system. The scheme, that we call quadrature chaos shift keying (QCSK), is based upon the generation of an orthogonal basis of chaotic functions. QCSK is characterized by an increased data rate with respect to DCSK, with the same bandwidth occupation. The price for the performance enhancem... View full abstract»

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  • Noise-robust synchronized chaotic communications

    Publication Year: 2001 , Page(s): 1519 - 1523
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (131 KB) |  | HTML iconHTML  

    Until now, research on the applications of self-synchronized chaotic circuits to communications has been hindered by the great sensitivity of self-synchronized chaotic systems to additive noise. In this paper, the author demonstrates a self-synchronized chaotic system that synchronizes even in the presence of noise much larger than the signal. This system works because it generates signals with tw... View full abstract»

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  • Chaotic wavelength-hopping device for multiwavelength optical communications

    Publication Year: 2001 , Page(s): 1519 - 1522
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (124 KB) |  | HTML iconHTML  

    We describe a laser device which generates wavelength-hopping sequences useful for optical communication. The wavelength-hopping sequences are generated using nonlinear dynamical behavior of a wavelength tunable laser with opto-electric feedback. Methods for data transmission using periodic and chaotic hopping sequences are described. View full abstract»

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  • Author index

    Publication Year: 2001 , Page(s): 1528 - 1534
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  • Subject index

    Publication Year: 2001 , Page(s): 1534 - 1551
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