Chaos-Based Digital Communication Systems

Abstract

PrefaceIn the 1970's and 1980's, we saw phenomenal advancement in nonlinear science, which had led to many important discoveries that greatly improve our understanding of the physical world. Among them, the discovery of chaos in deterministic systems is unarguably one of the most revolutionary scientific findings. We are now able to explain the apparent complexity and subtle order exhibited by many physical systems under the unified framework of chaos theory.The past decade has seen heightened interest in the exploitation of chaos for useful applications in engineering systems. One application area that has attracted a great deal of attention is communications. Chaotic signals, by virtue of their wide band characteristic, are natural candidates for carrying information in a spread-spectrum communication environment. The use of chaotic signals in communications thus naturally inherits the advantages that are currently being offered by conventional spread-spectrum communication systems, such as robustness in multi path environments, resistance to jamming, low probability of interception, etc. In addition, chaotic signals are easy to generate and hence offer a potentially low-cost solution to spreadspectrum communications.Although many practical problems need to be solved before chaos-based communications can be realized in practice, the field has advanced rapidly during the past few years and it now reaches a point where abstract concepts from physics and mathematics have been fruitfully ported to techniques that allow information to be carried by chaotic signals.This book is intended to address the basic system design, operation, analysis, and performance evaluation of a few selected chaos-based digital communication systems. We put emphasis on the analytical approach taken to study chaos-based communication systems, and focus our attention on a few performance aspects that are of practical importance. In particular, we discuss in this book the modulation techniques, error rate calculations, anti-jamming capabilities, and coexistence with conventional communication systems. We believe that the materials covered in this book will be useful to graduate students, researchers, communication engineers and technology developers who wish to exploit chaos for communication applications.viii We begin in Chapter 1 with an overview of spread-spectrum communication systems and the potential benefits of carrying information with chaotic signals. In Chapter 2 we introduce chaos-based digital modulations and discuss the salient concepts in encoding information with chaotic signals. A review of the various modulation schemes is given. Chapter 2 also contains a discussion on the use of equivalent discrete-time baseband models for studying chaos-based digital communication systems. This kind of models will be used throughout the book. Chapters 3 and 4 provide an indepth treatment of analytical techniques for calculating bit error probabilities of chaos-based digital communication systems. Both single-user and multi-user systems are...

Chaos-Based Underwater Communication With Arbitrary Transducers and Bandwidth

“…In this section, the conventional DCSK using logistic map [21], NR-DCSK [23], RM-DCSK [27], HE-DCSK [28], PS-DCSK [30], CDSK [31], and the proposed method with the same transmission rate are compared in the AWGN channel with different bit energy to noise power spectral density (E b /N 0 ) ratios. Figure 5 shows BER for the different methods versus E b /N 0 with the data transmission rate R b = 1000 bits/s, where the spreading gain L = 150, n samp = 10, N s = 15, and the frequency of the sinusoidal signal is f = 50 kHz.…”

“…The conventional DCSK [21], NR-DCSK [23], HE-DCSK [28], RM-DCSK [27], PS-DCSK [30], CDSK [31] and the proposed method are simulated over the underwater acoustic channel at different E b /N 0 levels. The optimal spreading gain L = 1000 (n samp = 10, N s = 100), f = 50 kHz are used for the proposed method, the conventional DCSK, NR-DCSK, CDSK, HE-DCSK, and RM-DCSK.…”

“…In Section 3, simulation results of the proposed method are given and compared with the conventional DCSK [21], NR-DCSK [23], RM-DCSK [27], HE-DCSK [28], Phase-Separate DCSK [30] (PS-DCSK) and correlation delay shift keying [31] (CDSK). Conclusions are given in Section 4.…”

Stable non-Gaussian noise parameter modulation in digital communication

“…As an alternative to the conventional digital communication systems, chaos-based digital communication techniques became popular by the beginning of the 1990s and chaotic signals have since been a proper candidate to ensure the security due to their broadband nature [1][2][3][4][5][6]. Chaotic signals have been used to encode the binary message bits with chaos shift keying techniques [4,5].…”

A General Noncoherent Chaos-Shift-Keying Communication System and its Performance Analysis

“…The early few proposed chaos-based communication schemes were all coherent systems which were based upon the idealized assumption that two or more chaotic systems can be synchronized. In digital implementations, the chaos shift keying (CSK) has been most widely studied and analyzed [6], [7]. However, as the assumption of the synchronizability of chaotic systems has been found unrealistic or invalid under practical channel conditions, research direction has shifted towards noncoherent schemes.…”