Performance Impact of Multiple Access Interference in a 4-ary Pulse Position Modulated Optical Code Division Multiple Access (PPM/O-CDMA) System

2008 ◽  
Author(s):  
V. J. Hernandez ◽  
A. J. Mendez ◽  
R. M. Gagliardi ◽  
C. V. Bennett ◽  
W. J. Lennon
Keyword(s):  
Code Division Multiple Access ◽  
Multiple Access ◽  
Multiple Access Interference ◽  
Cdma System ◽  
Performance Impact ◽  
Code Division Multiple

Performance Analysis of SAC Optical PPM-CDMA System-Based Interference Rejection Technique

2016 ◽  
Vol 37 (1) ◽  
Author(s):  
N. Alsowaidi ◽  
Tawfig Eltaif ◽  
M. R. Mokhtar
Keyword(s):  
Interference Cancellation ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Multiple Access Interference ◽  
Spectral Amplitude ◽  
Cdma System ◽  
Pulse Position Modulation ◽  
Interference Rejection ◽  
Spectral Amplitude Coding ◽  
Code Division Multiple

AbstractIn this paper, we aim to theoretically analyse optical code division multiple access (OCDMA) system that based on successive interference cancellation (SIC) using pulse position modulation (PPM), considering the interference between the users, imperfection cancellation occurred during the cancellation process and receiver noises. Spectral amplitude coding (SAC) scheme is used to suppress the overlapping between the users and reduce the receiver noises effect. The theoretical analysis of the multiple access interference (MAI)-limited performance of this approach indicates the influence of the size of

Performance Analysis of Spectral Amplitude Coding Optical Code Division Multiple Access System using Modified Double Weight Codes with Adomian Decomposition Method

2018 ◽  
Vol 39 (4) ◽  
pp. 459-462 ◽  
Author(s):  
Monika Rani ◽  
Harbax Singh Bhatti ◽  
Vikramjeet Singh
Keyword(s):  
Code Division Multiple Access ◽  
Multiple Access ◽  
Decomposition Method ◽  
Adomian Decomposition Method ◽  
Multiple Access Interference ◽  
Spectral Amplitude ◽  
Adomian Decomposition ◽  
Spectral Amplitude Coding ◽  
Code Division Multiple ◽  
Multiple Access System

Abstract In this manuscript, we have analyzed a Spectral Amplitude Coding-Optical Code Division Multiple Access (SAC-OCDMA) System. The system performance is enhanced by reducing the effect of Multiple Access Interference (MAI) using uniform Fiber Bragg Gratings (FBGs) encoders and decoders at central office and subscriber’s end. The results are verified through a mathematical model and Modified Double Weight (MDW) codes for the proposed system using Adomian Decomposition Method (ADM). Further, we have demonstrated SAC-OCDMA system for transmission of 40 Gbps data rate up to a distance of 80 km by increasing the number of FBGs. The proposed system has been analyzed in terms of distance, bit error rate (BER) and Quality Factor.

scholarly journals Incremental gradient algorithm for multiuser detection in multi-carrier DS-CDMA system under modulation schemes

2018 ◽  
Vol 7 (2.6) ◽  
pp. 311
Author(s):  
Sumitra N. Motade ◽  
Anju V. Kulkarni
Keyword(s):  
Spread Spectrum ◽  
Multiple Access ◽  
Minimum Mean Square Error ◽  
Multiple Access Interference ◽  
Gradient Algorithm ◽  
Channel Noise ◽  
Cdma System ◽  
Communication Performance ◽  
Optimum Performance ◽  
Code Division Multiple

Nowadays, Multicarrier Direct sequence code division multiple access (MC DS-CDMA) systems are used in mobile communication. Performance of these systems are limited by multiple access interference (MAI) created by spread-spectrum users in the channel as well as background channel noise. This paper proposes an incremental gradient descent (IGD) multi-user detection (MUD) for MC DS-CDMA system that can achieve near-optimum performance while the number of users is linear in its implementation complexity.  The IGD algorithm make an effort to perform optimum MUD by updating one user's bit decision each iteration in the best way. This algorithm accelerates the gradient algorithm convergence by averaging. When a minimum mean square error (MMSE) MUD is employed to initialize the proposed algorithm, in all cases tested the gradient search converges to a solution with optimum performance. Further, the iterative tests denote that the proposed IGD algorithm provides significant performance for cases where other suboptimum algorithms perform poorly. Simulation compares the proposed IGD algorithm with the conventional detectors. 

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.

scholarly journals The Channel Shortening comparison between OFDM & MC-CDMA System over an ADSL Channel using a Water-filling

2019 ◽  
Vol 9 (5) ◽  
pp. 3695
Author(s):  
Bouasria Fatima
Keyword(s):  
System Performance ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Digital Transmission ◽  
Cdma System ◽  
Channel Shortening ◽  
Multiple Paths ◽  
Water Filling ◽  
Cdma Systems ◽  
Code Division Multiple

<p>In this paper our objective focuses on the development of digital transmission techniques in order to solve the problem of Inter-Symbol Interference (ISI) due to multiple paths and the improvement of Multi-Carrier Code Division Multiple Access (MC-CDMA) system performance. The both algorithm: MERRY algorithm (Multicarrier Equalization by Restoration of Redundancy) called TEQ (Time domain EQualizer) and the power allocation method to allocate appropriate power to each user (Water-filling technique (WF)) [1] is used. Finally, the numerical results show that combining Water Filling with TEQ technique allows to reduce the ISI for MC-CDMA systems.</p>

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