Chaos Communication

CHAOTIC COMMUNICATION , THEIR APPLICATION AND ADVANTAGES 00000 OVER TRADITIONNAL METHODS OF COMMUNICATION

BY:RUDRAPPA J SHETTI 1KN05EC084

AGENDA •INTRODUCTION •DEFINITION OF CHAOS •CHAOTIC SYSTEM •CHAOTIC SIGNALS •ATTRACTORS •GENERATION OF CHAOTIC COMMUNICATION •PROPERTIES OF CHAOTIC COMMUNICATION •COMPARSION •ADVANTAGES OVER TRADITIONAL METHODS •APPLICATIONS •CONCLUSION •QUESTIONS

CHAOS Chaos is aperiodic time-asymptotic behaviour in a deterministic system which exhibits sensitive dependence on initial conditions This definition contains three main elements: 2.Aperiodic time-asymptotic behaviour--this implies the existence of phase-space trajectories which do not settle down to fixed points or periodic orbits. For practical reasons, we insist that these trajectories are not too rare. We also require the trajectories to be bounded: i.e., they should not go off to infinity. 3.Deterministic--this implies that the equations of motion of the system possess no random inputs. In other words, the irregular behaviour of the system arises from nonlinear dynamics and not from noisy driving forces. 4.Sensitive dependence on initial conditions--this implies that nearby trajectories in phase-space separate exponentially fast in time.

CHAOTIC All systems can be basically divided into three types: SYSTEMS 1.Deterministic systems

These are systems for which for a given set of conditions the result can be predicted and the output does not vary much with change in initial conditions

2. Stochastic systems

These systems, which are not as reliable as deterministic systems. Their output can be predicted only for a certain range of values.

3. Chaotic systems

Chaotic systems are the most unpredictable of the three systems. Moreover they are very sensitive to initial conditions and a small change in initial conditions can bring about a great change in its output.

CHAOTIC SIGNALS •Chaotic signals has broadband spectrum , hence the presence of information does not necessarily change the properties of the signal •Power output remains constant regardless of information content •It is resistant against multipath fading and offers cheaper solution to traditional spread spectrum systems

•Chaotic signals are complex in structure and impossible to predict over long time • chaotic signals appear noise like •Hence chaotic signal can be used for providing security at physical level

ATTRACTORS

DEFINITION An attractor is informally described as strange if it has non-integer dimension or if the dynamics on it are chaotic. Chaotic attractor is also known as a strange attractor, a type of attractor (i.e., an attracting set of states) in a complex dynamical system's phase space TYPES OF ATTRACTORS FIXED POINT LIMIT CYCLE

1.FIXED POINT

2. LIMIT CYCLE

An attractor that is represented by a particular point in phase space, sometimes called an equilibrium point. As a point it corresponds to a very limited range of possible behaviors of the system. A limit cycle is a periodic orbit of the system that is isolated.

HISTROY OF CHAOTIC SECURE COMMUNICATION SYSTEM First generation 1.Additive chaos masking 2.Chaotic shift keying Second generation 1.Chaotic parameter modulation 2.Chaotic non-autonomous modulation Third generation 1.Chaotic cryptosystem Forth generation 1.impulsive synchronization based cscs

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FIRST GENERATION

ØThe additive chaos masking scheme chann el

The Chua’s oscillator

The state equations for the Chua’s oscillator are given by

At transmitter

At receiver

The chaotic shift keying scheme ●

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SECOND GENERATION The chaotic parameter modulation.

message signal and its recovered

ØThe chaotic non-autonomous modulation. .

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THIRD GENERATION Øchaotic cryptosystem

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FOURTH GENERATION

The impulsive synchronization based chaotic secure communication system.

Time-frame and its components

Within every time frame, the synchronization region has a length of Q and the remaining time interval T -Q is the scrambled signal region

Properties for Communications :•Why are we interested in chaos? ØCertain properties of chaotic systems are appealing for communications such as 1. Low power 2. Broadband spectra 3. Noise-like appearance 4. Auto and cross correlation properties 5. Low multipath interference

WHY TO BOTHER WITH CHAOTIC Ø Digital msg sent at Gbps speeds over 115Kms Ø BER of one in ten million [ BER said to be limited by the equipment rather than the technique itself ] Ø Hard to detect by eavesdroppers Ø Less risk of interception

Conventional Sinusoidal-based Communication vs. Chaos-based Communication Conventional

Chaotic History: over 100 years old; less than 10 years matured technology Emerging technology Industrial Heart of world wide None existing base inform. Tech. Transmission Transmit either

Transmit at

Contd. Conventional Chaotic ØRelation between Distinct separation Many CC theory & Tech. between info. the./ sys. schemes comm. sys./comm. are described

Single-link Communication System Conventional Modulation non-BW expansion Formats: Anti-podal signals; masking; BPSK; BFSK modulation feedback Synchronization implementational

sync. is theory is only loss of fraction

Chaotic BW expansion Chaotic Parametric Dynamic

Chaotic still an

Cont d. Conven. Chaotic Encryption: Bit Prob. Error: known Complexity: complex

No Exist simple

yes No

Advantages over Traditional Methods 1. At high speed it is easier to generate strong , high power chaotic signals than periodic signals. 2. Chaotic signals are not sensitive to initial conditions and have a noise like time series. 3. Chaotic transmission has less risks of interception and are hard to detect by eavesdropper. 4. In chaotic communication, then on linear characteristic of communication devices are utilized instead of being avoided,

Application of chaos in digital communication

Applications ü Used in Ultra Wide Band radio. ü Used in radar and sonar. ü Used in oscillator. ü Used in Chaotic masking . ü Used in spread spectrum. ü Used for secure

CONCLUSION A very brief overview on Chaotic communication has been described, explaining the systems, signals,synchronisations and a brief of histroy Chaotic communication .The majority of research carried out , to prove Chaotic communication has advantages over traditinal communication system . At last but not least application of Chaotic communication

Thank you. (Any questions !!!)

BY : RUDRAPPA J SHETTI