Effect of multipath fading and multiple access interference on broadband code division multiple access systems

2011 ◽  
Vol 25 (7) ◽  
pp. 874-886 ◽  
Author(s):  
Md. Anwar Hossain ◽  
Mohammed Tarique
Keyword(s):  
Code Division Multiple Access ◽  
Multiple Access ◽  
Multiple Access Interference ◽  
Multipath Fading ◽  
Code Division Multiple

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 An Efficient Method to Reduce an MAI’s Effect in Spectral Amplitude Coding OCDMA Network

2017 ◽  
Vol 2 (6) ◽  
pp. 1
Author(s):  
Kamal Elsiddig Amaseb ◽  
Hassan Yousif Ahmed ◽  
Medien Zeghid
Keyword(s):  
Optical Communication ◽  
System Performance ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Multiple Access Interference ◽  
Spectral Amplitude ◽  
Integer Number ◽  
Quadratic Congruence ◽  
Spectral Amplitude Coding ◽  
Code Division Multiple

Multiple access interference (MAI) in spectral-amplitude coding, optical code division multiple access (SAC-OCDMA) scheme hardly limits the system performance. This problem increases proportionally with the amount of concurrent users. In addition, phase induces intensity noise (PIIN) coming from the spontaneous emission process of light source is extra impairment leads to system drop needs to be tackled too. Towards overcome the specified problems, vector combinatorial (VC) codes which based on grouping of certain vectors is proposed. Any positive integer number can be used in both weighs and user parameters in code building procedure, these technique nominees our code to be a potential reliable applicant for future optical communication schemes. Such flexibility is an exceptional property for VC compared to SAC-OCDMA counterparts’ codes. Compared with the systems employing Hadamard, Modified Frequency Hopping (MFH), Modified Quadratic-Congruence (MQC), and Modified Double Weight (MDW), numerical results show that, the VC is effective to reduce the power of MAI and PIIN. It has been exposed that, performance can be superior significantly when VC is used.

scholarly journals A proposed method for determination of weighted despreading sequences for a DS/CDMA system

2007 ◽  
Vol 3 (3) ◽  
Author(s):  
Younes Jabrane ◽  
Radouane Iqdour ◽  
Brahim Ait Es Said ◽  
Najib Naja
Keyword(s):  
Interference Cancellation ◽  
Fuzzy Systems ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Additive White Gaussian Noise ◽  
Multiple Access Interference ◽  
Code Division Multiple ◽  
Parameter Values ◽  
Gaussian Noise Channels

The steeping chip weighting waveforms are used in multiple access interference cancellation by emphasizing the received spreading signal, therefore, that allows to solve the problem of orthogonality for the chip waveforms. Our paper presents a useful method based on fuzzy systems to determine the despreading sequences weighted by the steeping chip weighting waveforms for Direct Sequence Code Division Multiple Access DS/CDMA. The validity of our proposed method has been tested by numerical examples for an Additive White Gaussian Noise channels and shows that the parameter values of the chip weighting waveforms are good and the Bit Error Rate performance of the system does not undergone any degradation.

scholarly journals Simulation Performance of CDMA/QA in Mobile Channel

2011 ◽  
Vol 5 (1) ◽  
pp. 14
Author(s):  
Khalid Hamid Bilal Abdalla
Keyword(s):  
Spread Spectrum ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Multipath Fading ◽  
Direct Sequence ◽  
Simulation Performance ◽  
Mobile Channel ◽  
Link Performance ◽  
Multiple Access Schemes ◽  
Code Division Multiple

The aim of this work is to study, analyze and evaluate software the link performance of mobile communication system under the impairment of the multiple access schemes, down-link thermal noise and the multipath fading in the mobile channel. For this purpose, modeling and simulation has been used to study the effects of nonlinearities in mobile channel using spread spectrum for Direct Sequence Code Division Multiple Access, with Quadrature Amplitude Modulation (DS-CDMA/QAM).

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