Performance enhancement of DS/CDMA system using chaotic complex spreading sequence

Kurian, Ajeesh P.; Puthusserypady, Sadasivan; Htut, Su Myat

doi:10.1109/twc.2005.847028

Cited by 61 publications

(43 citation statements)

References 22 publications

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“…Simulation parameters for the system under consideration are set according to the IEEE 801.11a standard [35] where 25 % of the total subcarriers N t are unused, (i.e N u = 25%N t ), N cp is equal to 4 and the size of FFT is chosen to accommodate the number of users and keep the system flexible to change the number of data M , where M ≤ N S given in equation (6). It is important to note that among N S subcarriers, the leftover subcarriers, i.e.…”

Section: Simulation Resultsmentioning

confidence: 99%

“…Various digital chaos-based communication schemes have been evaluated and analysed including coherent chaos-shiftkeying (CSK) [5], [9], [10], chaos-based DS-CDMA [8], [6], [7] and non-coherent Differential Chaos Shift Keying (DCSK) [11], [12], [13], [14]. In CSK and chaos-based DS-CDMA, chaotic sequences are used instead of conventional spreading codes to spread data signals.…”

Section: Introductionmentioning

confidence: 99%

“…The later is used in DS-CDMA. The usage of chaotic sequences enhances the security and the performance of the transmission [6] but such a scheme would require the generation and the synchronization of the chaotic sequence at the receiver side which is non-trivial. For instance, the chaotic synchronization proposed by Pecora and Carroll in [15] is still practically impossible to achieve in a noisy environment and, as a result, the coherent system can not be used in realistic applications.…”

Section: Introductionmentioning

confidence: 99%

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Design and Performance Analysis of a Multiuser OFDM Based Differential Chaos Shift Keying Communication System

Kaddoum

2016

IEEE Trans. Commun.

122

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Abstract-In this paper, a Multi-user OFDM based Chaos Shift Keying (MU OFDM-DCSK) modulation is presented. In this system, the spreading operation is performed in time domain over the multi-carrier frequencies. To allow the multiple access scenario without using excessive bandwidth, each user has NP predefined private frequencies from the N available frequencies to transmit its reference signal and share with the other users the remaining frequencies to transmit its M spread bits. In this new design, NP duplicated chaotic reference signals are used to transmit M bits instead of using M different chaotic reference signals as done in DCSK systems. Moreover, given that NP << M , the MU OFDM-DCSK scheme increases spectral efficiency, uses less energy and allows multiple-access scenario. Therefore, the use of OFDM technique reduces the integration complexity of the system where the parallel low pass filters are no longer needed to recover the transmitted data as in multicarrier DCSK scheme. Finally, the bit error rate performance is investigated under multi-path Rayleigh fading channels, in the presence of multi-user and additive white Gaussian noise interferences. Simulation results confirm the accuracy of our analysis and show the advantages of this new hybrid design.

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Section: Simulation Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Design and Performance Analysis of a Multiuser OFDM Based Differential Chaos Shift Keying Communication System

Kaddoum

2016

IEEE Trans. Commun.

122

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“…Taking into consideration the fact that chaotic signals have plenty of advantages like superb correlation properties, wideband peculiarities and easily-done generation, the use of this category of waveforms for wireless communications is recommended by many researchers [1], [2] and in particular for multiuser spread-spectrum communications [1], [3]- [7]. Chaos-based modulations provide the features mentioned herein while it does not cross the red lines preserved by spreadspectrum modulations like security of communications [8], jamming resistance and low probability of interception (LPI) [9] as well as mitigation of fading in time varying channels [10].…”

Section: Introductionmentioning

confidence: 99%

Design of a Short Reference Noncoherent Chaos-Based Communication Systems

Kaddoum

Soujeri

Nijsure

2016

IEEE Trans. Commun.

136

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Abstract-Data rate and energy efficiency decrement caused by the transmission of reference and data carrier signals in equal portions constitute the major drawback of differential chaos shift keying (DCSK) systems. To overcome this dominant drawback, a short reference DCSK system (SR-DCSK) is proposed. In SR-DCSK, the number of chaotic samples that constitute the reference signal is shortened to R such that it occupies less than half of the bit duration. To build the transmitted data signal, P concatenated replicas of R are used to spread the data. This operation increases data rate and enhances energy efficiency without imposing extra complexity onto the system structure. The receiver uses its knowledge of the integers R and P to recover the data. The proposed system is analytically studied and the enhanced data rate and bit energy saving percentages are computed. Furthermore, theoretical performance for AWGN and multipath fading channels are derived and validated via simulation. In addition, optimising the length of the reference signal R is exposed to detailed discussion and analysis. Finally, the application of the proposed short reference technique to the majority of transmit reference systems such as DCSK, multicarrier DCSK, and quadratic chaos shift keying enhances the overall performance of this class of chaotic modulations and is, therefore, promising.

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“…The detection is performed by using correlator-type receivers and this implies in a more complex communication system. Some well-known coherent modulations schemes are chaos shift keying (CSK) [11] and chaos-based DS-CDMA [14], where chaotic sequences are used to spread data signals. On the other hand, noncoherent modulation mitigates synchronization problems of chaotic oscillators at the receiver.…”

Section: Introductionmentioning

confidence: 99%

A smooth chaotic map with parameterized shape and symmetry

Chaves

Souza

Pimentel

2016

EURASIP J. Adv. Signal Process.

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We introduce in this paper a new chaotic map with dynamical properties controlled by two free parameters. The map definition is based on the hyperbolic tangent function, so it is called the tanh map. We demonstrate that the Lyapunov exponent of the tanh map is robust, remaining practically unaltered with the variation of its parameters. As the main application, we consider a chaotic communication system based on symbolic dynamics with advantages over current approaches that use piecewise linear maps. In this context, we propose a new measure, namely, the spread rate, to study the local structure of the chaotic dynamics of a one-dimensional chaotic map.

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Performance enhancement of DS/CDMA system using chaotic complex spreading sequence

Cited by 61 publications

References 22 publications

Design and Performance Analysis of a Multiuser OFDM Based Differential Chaos Shift Keying Communication System

Design and Performance Analysis of a Multiuser OFDM Based Differential Chaos Shift Keying Communication System

Design of a Short Reference Noncoherent Chaos-Based Communication Systems

A smooth chaotic map with parameterized shape and symmetry

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