A comparative analysis of an OCDMA system based on single Photodiode and spectral direct detection schemes

The main advantages for using Optical Code Division Multiple Access (OCDMA) are the flexibility of an asynchronous access method, increased security and graceful degradation. Over the last decade, many detection techniques have been proposed for OCDMA, especially for incoherent OCDMA systems. Prop...

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主要作者: Sarah Ghassan, Abdulqader
其他作者: Prof. Dr. Syed Alwee Aljunid Syed Junid
格式: Thesis
语言:English
出版: Universiti Malaysia Perlis (UniMAP) 2019
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在线阅读:http://dspace.unimap.edu.my:80/xmlui/handle/123456789/61539
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spelling my.unimap-615392019-08-23T09:51:37Z A comparative analysis of an OCDMA system based on single Photodiode and spectral direct detection schemes Sarah Ghassan, Abdulqader Prof. Dr. Syed Alwee Aljunid Syed Junid Optical Code Division Multiple Access (OCDMA) Photodiodes OCDMA networks Detection The main advantages for using Optical Code Division Multiple Access (OCDMA) are the flexibility of an asynchronous access method, increased security and graceful degradation. Over the last decade, many detection techniques have been proposed for OCDMA, especially for incoherent OCDMA systems. Proper detection selection is very important for good system performance and high network scalability with low bit-error rates (BERs) of less than 10−9. OCDMA systems, however, generally, suffer from multiple access interference (MAI) noise which originates from simultaneous users and severely increases the likelihood of bit errors. To mitigate this limitation, spectral amplitude coding (SAC) OCDMA is used throughout this thesis. The advantage of SAC-OCDMA over conventional OCDMA systems is that, when using appropriate detection techniques, the MAI can be totally suppressed. This either reduces the effect of the MAI or improves the performance even in the presence of MAI. In this thesis, spectral direct detection (SDD) and single-photodiode detection (SPD) techniques based on Modified Double weight (MDW) code, are investigated. The performance analysis of the suggested detection techniques are carried out through simulation experiments using Optisystem software from OptiwaveTM. Moreover, the structure of both detection techniques is based on one photodiode per user compared with other subtraction detection techniques. The comparative analysis shows that the SPD technique is a more capable solution for efficiently restraining interference signals in the optical domain before the signals are converted to the electrical domain. For MDW codes at a data rate of 622 Mbps and a BER of 1×10-10, the results showed that SPD can support more than 60 active users than the SDD technique. Part of the work is also devoted to investigating the feasibility of utilizing different types of optical filters (optical Gaussian, thin film and Fiber Bragg Grating (FBG) filters), and different data formats non-return-to-zero (NRZ) and return-to-zero (RZ). Employing the SPD technique not only provided a BER improvement over SDD, but was used for a large number of users at multiple rates of transmission with cost-effective light sources, and for longer transmission distances. 2019-08-23T09:51:37Z 2019-08-23T09:51:37Z 2014 Thesis http://dspace.unimap.edu.my:80/xmlui/handle/123456789/61539 en Universiti Malaysia Perlis (UniMAP) School of Computer and Communication Engineering
institution Universiti Malaysia Perlis
building UniMAP Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider Universiti Malaysia Perlis
content_source UniMAP Library Digital Repository
url_provider http://dspace.unimap.edu.my/
language English
topic Optical Code Division Multiple Access (OCDMA)
Photodiodes
OCDMA networks
Detection
spellingShingle Optical Code Division Multiple Access (OCDMA)
Photodiodes
OCDMA networks
Detection
Sarah Ghassan, Abdulqader
A comparative analysis of an OCDMA system based on single Photodiode and spectral direct detection schemes
description The main advantages for using Optical Code Division Multiple Access (OCDMA) are the flexibility of an asynchronous access method, increased security and graceful degradation. Over the last decade, many detection techniques have been proposed for OCDMA, especially for incoherent OCDMA systems. Proper detection selection is very important for good system performance and high network scalability with low bit-error rates (BERs) of less than 10−9. OCDMA systems, however, generally, suffer from multiple access interference (MAI) noise which originates from simultaneous users and severely increases the likelihood of bit errors. To mitigate this limitation, spectral amplitude coding (SAC) OCDMA is used throughout this thesis. The advantage of SAC-OCDMA over conventional OCDMA systems is that, when using appropriate detection techniques, the MAI can be totally suppressed. This either reduces the effect of the MAI or improves the performance even in the presence of MAI. In this thesis, spectral direct detection (SDD) and single-photodiode detection (SPD) techniques based on Modified Double weight (MDW) code, are investigated. The performance analysis of the suggested detection techniques are carried out through simulation experiments using Optisystem software from OptiwaveTM. Moreover, the structure of both detection techniques is based on one photodiode per user compared with other subtraction detection techniques. The comparative analysis shows that the SPD technique is a more capable solution for efficiently restraining interference signals in the optical domain before the signals are converted to the electrical domain. For MDW codes at a data rate of 622 Mbps and a BER of 1×10-10, the results showed that SPD can support more than 60 active users than the SDD technique. Part of the work is also devoted to investigating the feasibility of utilizing different types of optical filters (optical Gaussian, thin film and Fiber Bragg Grating (FBG) filters), and different data formats non-return-to-zero (NRZ) and return-to-zero (RZ). Employing the SPD technique not only provided a BER improvement over SDD, but was used for a large number of users at multiple rates of transmission with cost-effective light sources, and for longer transmission distances.
author2 Prof. Dr. Syed Alwee Aljunid Syed Junid
author_facet Prof. Dr. Syed Alwee Aljunid Syed Junid
Sarah Ghassan, Abdulqader
format Thesis
author Sarah Ghassan, Abdulqader
author_sort Sarah Ghassan, Abdulqader
title A comparative analysis of an OCDMA system based on single Photodiode and spectral direct detection schemes
title_short A comparative analysis of an OCDMA system based on single Photodiode and spectral direct detection schemes
title_full A comparative analysis of an OCDMA system based on single Photodiode and spectral direct detection schemes
title_fullStr A comparative analysis of an OCDMA system based on single Photodiode and spectral direct detection schemes
title_full_unstemmed A comparative analysis of an OCDMA system based on single Photodiode and spectral direct detection schemes
title_sort comparative analysis of an ocdma system based on single photodiode and spectral direct detection schemes
publisher Universiti Malaysia Perlis (UniMAP)
publishDate 2019
url http://dspace.unimap.edu.my:80/xmlui/handle/123456789/61539
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score 13.250246