Dynamic optical code division multiple access communication system analysis and performance enhancement by signal clipping

2005 ◽  
Author(s):  
Mohammad M. N. Hamarsheh ◽  
Mohamad K. Abdullah ◽  
M. A. Mahdi ◽  
S. Khatun ◽  
Hossam M. H. Shalaby
Keyword(s):  
Communication System ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
System Analysis ◽  
Performance Enhancement ◽  
And Performance ◽  
Code Division Multiple

scholarly journals A fractional Fourier transform–based channel estimation algorithm in single-carrier direct sequence code division multiple access underwater acoustic communication system

2019 ◽  
Vol 15 (1) ◽  
pp. 155014771982600 ◽  
Author(s):  
Lin Zhou ◽  
Qingsheng Zhao ◽  
Shukai Chi ◽  
Yanlong Li ◽  
Lanjun Liu ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Communication System ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Fractional Fourier Transform ◽  
Direct Sequence ◽  
Underwater Acoustic ◽  
Single Carrier ◽  
Sequence Code ◽  
Code Division Multiple

Due to the complexity and variability of the underwater acoustic channel, the communication signal is affected by multi-path, time delay, and Doppler frequency shift. Based on the advantageous characteristics of fractional Fourier transform on chirp signal processing, a fractional Fourier transform–based algorithm using combined linear frequency–modulated signal is proposed, which can estimate parameters of underwater acoustic channel and has a better performance than the existing methods. To distinguish multi-user in underwater acoustic communication system, a single-carrier direct sequence code division multiple access communication system combined with the fractional Fourier transform–based algorithm is proposed. Thus, a preliminary study on underwater multi-target identification is carried out. The simulation and experimental results show that the fractional Fourier transform–based algorithm is simple and effective, and the energy can be focused at the “best” fractional order, which can directly determine the multi-path number and complete the channel estimation. The proposed single-carrier direct sequence code division multiple access communication system has good performance on bit error rate when we use corresponding spreading code to distinguish multi-user.

Research on Key Technologies in Multi-Robotic Spread Spectrum Communication System

2013 ◽  
Vol 756-759 ◽  
pp. 2401-2405 ◽  
Author(s):  
Yun Hang Zhu ◽  
Qiong Cai ◽  
Xiu Liang Huang
Keyword(s):  
Spread Spectrum ◽  
Communication System ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Rapid Development ◽  
Direct Sequence Spread Spectrum ◽  
Robotic System ◽  
Direct Sequence ◽  
Walsh Code ◽  
Code Division Multiple

It has become a hot research topic that to improve the coordination performance of multi-robotic system by communication. With rapid development of wireless communication and robot technologies, multi-robotic system based on spread-spectrum technology has become product of combining two technologies. Code Division Multiple Access (CDMA) technology is applied in multi-robotic communication system here. According to the modified m-Walsh sequence got by the way of analyzing the relation characteristic of Walsh-code and m-sequence, the best direct sequence spread spectrum (DSSS) PN code and the improved RAKE receiver scheme are proposed, which satisfied the requirements of real-time performance, reliability and confidentiality in multi-robotic communication system, and have great significance for the research of multi-robotic communication system.

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