scholarly journals Improved Chaotic Sequence Generation Method Based on Direct Spread Spectrum

2019 ◽  
Vol 1237 ◽  
pp. 042006
Author(s):  
Fang Liu ◽  
Shiyao Jia ◽  
Xiaodan Xu ◽  
Minghao Tian
Keyword(s):  
Spread Spectrum ◽  
Chaotic Sequence ◽  
Sequence Generation ◽  
Direct Spread

Design of Logistic Map-Based Spreading Sequence Generation for Use in Wireless Communication

2015 ◽  
pp. 81-121 ◽  
Author(s):  
Katyayani Kashayp ◽  
Kandarpa Kumar Sarma ◽  
Manash Pratim Sarma
Keyword(s):  
Wireless Communication ◽  
Spread Spectrum ◽  
Logistic Map ◽  
Chaotic Sequence ◽  
Wireless Channel ◽  
Computational Time ◽  
Spreading Sequence ◽  
Sequence Generation ◽  
Critical Issues ◽  
Code Division Multiple

Spread spectrum modulation (SSM) finds important place in wireless communication primarily due to its application in Code Division Multiple Access (CDMA) and its effectiveness in channels fill with noise like signals. One of the critical issues in such modulation is the generation of spreading sequence. This chapter presents a design of chaotic spreading sequence for application in a Direct Sequence Spread Spectrum (DS SS) system configured for a faded wireless channel. Enhancing the security of data transmission is a prime issue which can better be addressed with a chaotic sequence. Generation and application of chaotic sequence is done and a comparison with Gold sequence is presented which clearly indicates achieving better performance with simplicity of design. Again a multiplierless logistic map sequence is generated for lower power requirements than the existing one. The primary blocks of the system are implemented using Verilog and the performances noted. Experimental results show that the proposed system is an efficient sequence generator suitable for wideband systems demonstrating lower BER levels, computational time and power requirements compared to traditional LFSR based approaches.

SIMULATION OF DIRECT SPREAD SPECTRUM COMMUNICATION SYSTEM ON THE HARDWARE MODULE EMONA DATEX. EVALUATION OF THE EFFECT OF NOISE ON THE QUALITY OF DEMODULATION

2019 ◽  
Author(s):  
Maksim Zhmakin ◽  
Irina Chadyuk ◽  
Aleksey Nadymov
Keyword(s):  
Spread Spectrum ◽  
Communication System ◽  
Spread Spectrum Communication ◽  
Direct Spread ◽  
Simulation Results

A variant of implementation of a communication system with direct spread spectrum is presented in this article, simulation results are also presented, the main parameters of the system are taken, and conclusions are drawn.

Dynamic Logistic Map Based Spread Spectrum Modulation in Wireless Channels

2018 ◽  
Vol 9 (2) ◽  
pp. 52-65
Author(s):  
Katyayani Kashyap ◽  
Tarun Kumar Sharma
Keyword(s):  
Spread Spectrum ◽  
Wireless Channels ◽  
Logistic Map ◽  
Chaotic Sequence ◽  
Direct Sequence Spread Spectrum ◽  
Computational Time ◽  
Sequence Length ◽  
Spreading Sequence ◽  
Nonlinear Channels ◽  
Spread Spectrum Modulation

Generation of an efficient spreading code in Spread Spectrum Modulation (SSM) is always challenging due to considerations like optimum sequence length, physical layout of registers and power requirements. In this article, a design of a dynamic chaotic spreading sequence for application in a Direct Sequence Spread Spectrum (DS SS) based system with the considerations of wireless channels (Rayleigh and Rician) are presented. Generation of dynamic chaotic sequence for application in linear and nonlinear channels is done and a comparison with static chaotic sequence is presented. Evaluation of performance is done in terms of bit error rate (BER), computational time, mutual information and signal power for faded channel taking into considerations of different modulation schemes, which finally dictates the efficiency of the generated code. The performance of the generated dynamic logistic map-based sequence is compared to that obtained from Gold code under equivalent conditions.

New Binary Code Combined with New Chaotic Map and Gold Code to Ameliorate the Quality of the Transmission

2017 ◽  
Vol 5 (1) ◽  
pp. 166
Author(s):  
Mohamed Krim ◽  
Adda Ali-Pacha ◽  
Naima Hadj-Said
Keyword(s):  
Spread Spectrum ◽  
Communication Systems ◽  
Binary Code ◽  
Chaotic Map ◽  
Research Problem ◽  
Chaotic Sequence ◽  
Scanning System ◽  
Radio Communications ◽  
Gold Code

<p>While the private radio communications field has grown in recent years, the communication method known as spread spectrum name has gained much prominence. A spread spectrum method can be combined with multiple access method CDMA for dividing sequences to create multi-user communication systems with very good performance of interference between symbols.The production of the chaotic sequence in scanning system and the information system according to DS-CDMA remains a hot research problem in this study to supervise in the knowledge wireless communication. This fact is still a question in establishing the secret code random spread sequence between the transmitter and the receiver.In DS-SS’s spreading is important to embed security information.It can avoid many problems in the complex calculation of the true circle. Furthermore the pseudo chaotic is reconstructed in the conventional gold to change shape with the logical operator “XOR” the results in simulation result shows in progress.It improves also the computing speed as this can solve the new equation of the problem in the original logistic map.There certainly has a kind in design: spreading chaotic sequence, chaos with gold code; including the number of users.So these are less in number and also limit the security and to can improve the ameliorate the quality of the transmissionand performance in terms of allowable number of users.The Bit error rate (BER) performance of the system is evaluated in multi-user environment under AWGN and reveals that the DS-SS system using new binary code combined with new logistic mapand gold code to ameliorate the quality of the transmission.</p>

scholarly journals Emerging 5G Multicarrier Chaotic Sequence Spread Spectrum Technology for Underwater Acoustic Communication

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Wu Jinqiu ◽  
Qiao Gang ◽  
Kang Pengbin
Keyword(s):  
Spread Spectrum ◽  
Filter Bank ◽  
Chaotic Sequence ◽  
Spectrum Efficiency ◽  
Underwater Acoustic Communication ◽  
Frequency Division ◽  
Underwater Acoustic ◽  
Multicarrier Communication ◽  
Fifth Generation ◽  
Communication Technique

Generalized frequency division multiplexing (GFDM) is a newly introduced technique for the wireless fifth-generation (5G) standard based on multicarrier filter bank theory, which has the advantage of flexibility in setting the number of subcarriers and subblocks. The application of GFDM in underwater acoustic (UWA) communication can take full advantage of the limited spectral resources, which is a prime limitation in UWA communication and will promote the development of UWA network technology. However, the multicarrier communication technique utilized in radio 5G communication offers difficulty in channel estimation, and the influence of a channel cannot be ignored especially in the UWA communication field. Therefore, GFDM cannot be implemented directly in UWA communication; to solve this problem, a system combining chaotic sequence spread spectrum technology with GFDM is proposed, which is a novel technique with high spectrum efficiency. Simulation and experimental results verified the effectiveness of the proposed system.

PERFORMANCE ANALYSIS OF MULTIPLE ACCESS CHAOTIC-SEQUENCE SPREAD-SPECTRUM COMMUNICATION SYSTEMS USING PARALLEL INTERFERENCE CANCELLATION RECEIVERS

2004 ◽  
Vol 14 (10) ◽  
pp. 3633-3646 ◽  
Author(s):  
WAI M. TAM ◽  
FRANCIS C. M. LAU ◽  
CHI K. TSE
Keyword(s):  
Spread Spectrum ◽  
Interference Cancellation ◽  
Communication Systems ◽  
Multiple Access ◽  
Minimum Mean Square Error ◽  
Chaotic Sequence ◽  
Spread Spectrum Communication ◽  
Parallel Interference Cancellation ◽  
Decorrelating Detector ◽  
Error Detector

In this Letter, we apply combined linear detector/parallel interference cancellation (PIC) detectors to jointly decode symbols in a multiple access chaotic-sequence spread-spectrum communication system. In particular, three different types of linear detectors, namely single-user detector, decorrelating detector and minimum mean-square-error detector, are used to estimate the transmitted symbols at the first stage of the PIC detector. The technique for deriving the approximate bit error rate (BER) is described and computer simulations are performed to verify the analytical BERs.

scholarly journals Research on Formation of Microsatellite Communication with Genetic Algorithm

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Guoqiang Wu ◽  
Yuguang Bai ◽  
Zhaowei Sun
Keyword(s):  
Spread Spectrum ◽  
Communication System ◽  
Formation Flying ◽  
Design Method ◽  
Ldpc Code ◽  
Spread Spectrum Communication ◽  
Design System ◽  
Generic Algorithm ◽  
Optimizing Design ◽  
Direct Spread

For the formation of three microsatellites which fly in the same orbit and perform three-dimensional solid mapping for terra, this paper proposes an optimizing design method of space circular formation order based on improved generic algorithm and provides an intersatellite direct spread spectrum communication system. The calculating equation of LEO formation flying satellite intersatellite links is guided by the special requirements of formation-flying microsatellite intersatellite links, and the transmitter power is also confirmed throughout the simulation. The method of space circular formation order optimizing design based on improved generic algorithm is given, and it can keep formation order steady for a long time under various absorb impetus. The intersatellite direct spread spectrum communication system is also provided. It can be found that, when the distance is 1 km and the data rate is 1 Mbps, the input wave matches preferably with the output wave. And LDPC code can improve the communication performance. The correct capability of (512, 256) LDPC code is better than (2, 1, 7) convolution code, distinctively. The design system can satisfy the communication requirements of microsatellites. So, the presented method provides a significant theory foundation for formation-flying and intersatellite communication.

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