DRIVING SYNCHRONIZATION OF SPATIOTEMPORAL CHAOS AND ITS APPLICATIONS IN CDMA COMMUNICATIONS

2001 ◽  
Vol 11 (12) ◽  
pp. 3117-3124
Author(s):  
REN YONG ◽  
YONGXIANG XIA ◽  
XIUMING SHAN ◽  
YUAN JIAN
Keyword(s):  
Communication Systems ◽  
Original System ◽  
Spatiotemporal Chaos ◽  
Sequence Generation ◽  
Chaotic Sequences ◽  
Spatial Periodicity ◽  
Pseudo Noise ◽  
Code Division Multiple ◽  
User Interference ◽  
Spreading Sequences

This paper investigates the driving synchronization of spatiotemporal chaos. Using this method, synchronization could be achieved efficiently. By improving the driving sequence generation method, the spatial periodicity in the original system is overcome. Large quantities of chaotic sequences are available, which possess the excellent properties expected in Code Division Multiple Access (CDMA) communications. These chaotic sequences can be used as the spreading sequences in place of the traditional pseudo-noise sequences. We also evaluate the performance of the chaotic CDMA communication systems and compute the average bit error rate caused by the multi-user interference and the noise in the channel. The theoretical and simulation results show the excellent performance of the scheme.

scholarly journals Statistical Analysis of Multiple Access Interference in Chaotic Spreading Sequence Based DS-CDMA Systems

2017 ◽  
Vol 21 (1) ◽  
pp. 34
Author(s):  
A. Litvinenko ◽  
E. Bekeris
Keyword(s):  
Statistical Analysis ◽  
Communication Systems ◽  
Multiple Access ◽  
Multiple Access Interference ◽  
Matlab Simulation ◽  
Spreading Sequence ◽  
Sequence Generation ◽  
Code Division Multiple ◽  
Correlation Properties ◽  
Spreading Sequences

This paper presents a statistical analysis of multiple access interference (MAI) in Direct Sequence Code Division Multiple Access (DS-CDMA) communication systems based on different types of chaotic spreading sequences. The probability distribution of the interference in a system with K users causing the MAI is studied using MATLAB simulation. For chaotic spreading sequence generation six different 1-D chaotic maps are used: modified Bernoulli, modified Tent, Gauss, Sine-Circle, Cubic and Pinchers map. A brief statistical analysis of the cross-correlation properties of the chaotic sequences generated by the aforementioned maps is also presented.

scholarly journals Suitable Spreading Sequences for Asynchronous MC-CDMA Systems

2018 ◽  
Vol 3 ◽  
pp. 9-13 ◽  
Author(s):  
Mouad Addad ◽  
Ali Djebbari
Keyword(s):  
Communication Systems ◽  
Multiple Access ◽  
Signal To Noise Ratio ◽  
Multiple Access Interference ◽  
High Data ◽  
Research Areas ◽  
Rate Transmission ◽  
Cdma Systems ◽  
Code Division Multiple ◽  
Spreading Sequences

In order to meet the demand of high data rate transmission with good quality maintained, the multi-carrier code division multiple access (MC-CDMA) technology is considered for the next generation wireless communication systems. However, their high crest factor (CF) is one of the major drawbacks of multi-carrier transmission systems. Thus, CF reduction is one of the most important research areas in MC-CDMA systems. In addition, asynchronous MC-CDMA suffers from the effect of multiple access interference (MAI), caused by all users active in the system. Degradation of the system’s bit error rate (BER) caused by MAI must be taken into consideration as well. The aim of this paper is to provide a comparative study on the enhancement of performance of an MC-CDMA system. The spreading sequences used in CDMA play an important role in CF and interference reduction. Hence, spreading sequences should be selected to simultaneously ensure low CF and low BER values. Therefore, the effect that correlation properties of sequences exert on CF values is investigated in this study. Furthermore, a numerical BER evaluation, as a function of the signal-to-noise ratio (SNR) and the number of users, is provided. The results obtained indicate that a trade-off between the two criteria is necessary to ensure good performance. It was concluded that zero correlation zone (ZCZ) sequences are the most suitable spreading sequences as far as the satisfaction of the above criteria is concerned.

Orthogonal Signals and the Orthogonalization Procedure

2021 ◽  
pp. 18-55
Author(s):  
Stevan Berber
Keyword(s):  
Spread Spectrum ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Theory And Practice ◽  
Schmidt Orthogonalization ◽  
Code Division Multiple ◽  
Digital Communication Systems ◽  
Spreading Sequences ◽  
Multiplexing Systems ◽  
Orthogonalization Procedure

Chapter 2 is dedicated to the principle of signal orthogonalization, because orthogonal signals are widely used in telecommunication theory and practice, like the carriers of baseband signals, subcarriers in orthogonal frequency division multiplexing systems, and the spreading sequences in spread-spectrum and code division multiple access (CDMA) systems. The orthonormal basis functions are defined and the procedure of the vector representation of signals is demonstrated. The Gram–Schmidt orthogonalization procedure and construction of the space diagram are presented in detail. Using orthonormal signals, signal synthesizers and analysers that can be used to form discrete-time transmitters and receivers are theoretically founded. Understanding of this chapter is a prerequisite for understanding Chapters 4–10, because the orthonormal signals defined in this chapter will be used throughout the book. The basis harmonic orthonormal functions will define the carriers in the discrete and digital communication systems.

MULTI-USER RECEIVERS FOR SPREAD SPECTRUM COMMUNICATIONS BASED ON CHAOTIC SEQUENCES

2002 ◽  
Vol 12 (04) ◽  
pp. 847-853 ◽  
Author(s):  
FRANCISCO ARGÜELLO ◽  
MANUEL BUGALLO ◽  
MARGARITA AMOR
Keyword(s):  
Spread Spectrum ◽  
Interference Cancellation ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Detection Methods ◽  
Chaotic Sequences ◽  
Spread Spectrum Communications ◽  
Single User ◽  
Pseudo Noise ◽  
Code Division Multiple

Spread spectrum based on chaotic sequences is an alternative to spread spectrum based on pseudo-noise sequences. In this letter we present the application of two multi-user detection methods (parallel and successive interference cancellation schemes) to this type of code division multiple access. We demonstrate that, also for chaotic sequence-based communications, multi-user receivers significantly improve the BER with respect to single-user receivers, and that their use is practically essential with a high number of users.

scholarly journals Computationally Efficient Chaotic Spreading Sequence Selection for Asynchronous DS-CDMA

2017 ◽  
Vol 13 (1) ◽  
pp. 75-80
Author(s):  
Anna Litviņenko ◽  
Artūrs Āboltiņš
Keyword(s):  
Multiple Access ◽  
Cross Correlation ◽  
Search Algorithm ◽  
Multiple Access Interference ◽  
Sequence Length ◽  
Spreading Sequence ◽  
Chaotic Sequences ◽  
Code Division Multiple ◽  
The Impact ◽  
Spreading Sequences

Abstract The choice of the spreading sequence for asynchronous direct-sequence code-division multiple-access (DS-CDMA) systems plays a crucial role for the mitigation of multiple-access interference. Considering the rich dynamics of chaotic sequences, their use for spreading allows overcoming the limitations of the classical spreading sequences. However, to ensure low cross-correlation between the sequences, careful selection must be performed. This paper presents a novel exhaustive search algorithm, which allows finding sets of chaotic spreading sequences of required length with a particularly low mutual cross-correlation. The efficiency of the search is verified by simulations, which show a significant advantage compared to non-selected chaotic sequences. Moreover, the impact of sequence length on the efficiency of the selection is studied.

scholarly journals Optimized PN Sequence Generation using Elliptic Curve Cryptography and UWD

2019 ◽  
Vol 8 (2S11) ◽  
pp. 2085-2090
Keyword(s):  
Elliptic Curve ◽  
Elliptic Curve Cryptography ◽  
Signal Transmission ◽  
Random Noise ◽  
Original Data ◽  
Pn Sequence ◽  
Sequence Generation ◽  
Pseudo Noise ◽  
Code Division Multiple ◽  
Performance Results

The Code Division Multiple Access (CDMA) technique is developed for military applications and also utilized in civilian application for the need of information hiding and secure signal transmission. The major issue occurs during the transmission in CDMA system is the security of data. In this proposed work, Universal Wind Driven (UWD) optimized ECC based PN sequence generation. Initially Pseudo Noise (PN) sequence is generated on the basis of Elliptic Curve Cryptography (ECC). The PN sequences have the characteristics of being like random noise with low correlation compared to any other sequence in the set. The original data is combined with optimal PN sequence and modulated by BPSK modulation and transmitted through the AWGN channel and demodulated by BPSK demodulation. The performance results proved that proposed work is efficient compared to other techniques.

A Method of Constructing Quaternary Periodic Complementary Sequence Sets for Suppression of Multiple Access Interference in CDMA Communication Systems

2014 ◽  
Vol 543-547 ◽  
pp. 2323-2328
Author(s):  
Fan Xin Zeng ◽  
Zhen Yu Zhang ◽  
Lin Jie Qian
Keyword(s):  
Communication System ◽  
Communication Systems ◽  
Multiple Access ◽  
Binary Sequence ◽  
Multiple Access Interference ◽  
New Method ◽  
Complementary Sequence ◽  
The One ◽  
Spreading Sequences

For suppressing multiple access interference (MAI) in a CDMA communication system, complementary sequence sets are employed as spreading sequences in such system. In this paper, we present a method for constructing a family of quaternary periodic complementary sequence sets, which arises from the conversion of the existing binary periodic complementary sequence sets with odd period of sub-sequences. The period of sub-sequences in the proposed sequence sets is twice as long as the one of the binary sequence sets employed, which is a drawback in the proposed method. Finally, some examples are given in order to illuminate the validity of the new method.

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