scholarly journals Concatenative Complete Complementary Code Division Multiple Access and its Fast Transform based Implementation

2021 ◽  
Author(s):  
Hikaru Mizuyoshi ◽  
chenggao han
Keyword(s):  
Code Division Multiple Access ◽  
Multiple Access ◽  
Hadamard Matrix ◽  
Average Power ◽  
Doppler Frequency ◽  
Spreading Factor ◽  
Fast Transforms ◽  
Fast Transform ◽  
Code Division Multiple ◽  
Doppler Frequency Shifts

Over multipath channels, \textit{complete complementary code division multiple access} (CC-CDMA) and \textit{convolutional spreading code division multiple access} (CS-CDMA) provide {\it inter-channel interference} (ICI) free transmission with an enhanced {\it spectral efficiency} (SE). However, the {\it convolutional spreading} (CS) operation of the systems is computationally complex and involves a high \textit{peak-to-average power ratio} (PAPR). Address such issues, we propose the \textit{concatenative complete complementary code division multiple access} (CCC-CDMA). Since the CCCCs can be generated from the rows of the Walsh-Hadamard or \textit{discrete Fourier transform} (DFT) matrices, the CS operation can be implemented using corresponding {\it fast transforms} (FTs) to reduce computational complexity. Simulation results shown that enlargement of {\it spreading factor} (SF) strengthens the robustness against clipping noise and the binary CCCC generated by Walsh-Hadamard matrix has excellent robustness against Doppler frequency shifts.

scholarly journals Concatenative Complete Complementary Code Division Multiple Access and its Fast Transform based Implementation

2021 ◽  
Author(s):  
Hikaru Mizuyoshi ◽  
chenggao han
Keyword(s):  
Code Division Multiple Access ◽  
Multiple Access ◽  
Hadamard Matrix ◽  
Average Power ◽  
Doppler Frequency ◽  
Spreading Factor ◽  
Fast Transforms ◽  
Fast Transform ◽  
Code Division Multiple ◽  
Doppler Frequency Shifts

Over multipath channels, \textit{complete complementary code division multiple access} (CC-CDMA) and \textit{convolutional spreading code division multiple access} (CS-CDMA) provide {\it inter-channel interference} (ICI) free transmission with an enhanced {\it spectral efficiency} (SE). However, the {\it convolutional spreading} (CS) operation of the systems is computationally complex and involves a high \textit{peak-to-average power ratio} (PAPR). Address such issues, we propose the \textit{concatenative complete complementary code division multiple access} (CCC-CDMA). Since the CCCCs can be generated from the rows of the Walsh-Hadamard or \textit{discrete Fourier transform} (DFT) matrices, the CS operation can be implemented using corresponding {\it fast transforms} (FTs) to reduce computational complexity. Simulation results shown that enlargement of {\it spreading factor} (SF) strengthens the robustness against clipping noise and the binary CCCC generated by Walsh-Hadamard matrix has excellent robustness against Doppler frequency shifts.

scholarly journals 2 Performance Evaluation of Code Division Multiple Access (CDMA) in terms of Power Measurement and Reduction

2011 ◽  
Vol 1 (1) ◽  
pp. 4
Author(s):  
Syed Rizwan-ul- Hasan ◽  
Shakil Ahmed
Keyword(s):  
Performance Evaluation ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Average Power ◽  
Power Measurement ◽  
Cdma System ◽  
Power Ratio ◽  
Ratio Measurement ◽  
Simulation Results ◽  
Code Division Multiple

 In this research paper the performance of the CDMA system has been analyzed with respect to PAPR (Peak to Average Power Ratio) measurement and its reduction. Simulation results verify that high peaks degrade the performance of CDMA, application of codes reduced high peaks and PAPR is a good measure for CDMA.

A New Construction of Optical Zero-Correlation Zone Codes

2018 ◽  
Vol 39 (3) ◽  
pp. 359-368 ◽  
Author(s):  
Benattou Fassi ◽  
Abdelmalik Taleb-Ahmed
Keyword(s):  
Code Division Multiple Access ◽  
Multiple Access ◽  
Hadamard Matrix ◽  
Access System ◽  
Zero Correlation ◽  
Channel Interference ◽  
New Construction ◽  
Zero Correlation Zone ◽  
Code Division Multiple ◽  
Multiple Access System

Abstract A new method for constructing optical zero-correlation zone (OZCZ) codes based on the Hadamard matrix and the concatenation operation is proposed. The most important property of the obtained codes is that the periodic correlation function of the proposed codes is zero for the phase shifts within the zero-correlation zone. The structure of the proposed OZCZ code is simple and their construction is more flexible. The proposed code is expected to be useful for reducing co-channel interference in optical code division multiple access system.

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