Multiple Access Interference and Interferometric Noise Suppression Using Dispersion Imbalanced Loop Mirror in Optical CDMA Networks

2009 ◽  
Author(s):  
Yanhua Deng ◽  
Mable P. Fok ◽  
Paul R. Prucnal
Keyword(s):  
Multiple Access ◽  
Noise Suppression ◽  
Multiple Access Interference ◽  
Optical Cdma ◽  
Cdma Networks ◽  
Interferometric Noise ◽  
Loop Mirror

scholarly journals BER Analysis Using Beat Probability Method of 3D Optical CDMA Networks with Double Balanced Detection

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Chih-Ta Yen ◽  
Chih-Ming Chen
Keyword(s):  
System Performance ◽  
Multiple Access ◽  
Three Dimensional ◽  
Multiple Access Interference ◽  
Optical Cdma ◽  
Probability Method ◽  
Detection Mechanism ◽  
Cdma Networks ◽  
Balanced Detection ◽  
Code Division Multiple

This study proposes novel three-dimensional (3D) matrices of wavelength/time/spatial code for code-division multiple-access (OCDMA) networks, with a double balanced detection mechanism. We construct 3D carrier-hopping prime/modified prime (CHP/MP) codes by extending a two-dimensional (2D) CHP code integrated with a one-dimensional (1D) MP code. The corresponding coder/decoder pairs were based on fiber Bragg gratings (FBGs) and tunable optical delay lines integrated with splitters/combiners. System performance was enhanced by the low cross correlation properties of the 3D code designed to avoid the beat noise phenomenon. The CHP/MP code cardinality increased significantly compared to the CHP code under the same bit error rate (BER). The results indicate that the 3D code method can enhance system performance because both the beating terms and multiple-access interference (MAI) were reduced by the double balanced detection mechanism. Additionally, the optical component can also be relaxed for high transmission scenery.

A Study of Bipolar Walsh-Hadamard Coding Method in Optical CDMA Networks

2013 ◽  
Vol 284-287 ◽  
pp. 2667-2671
Author(s):  
Chih Ta Yen ◽  
Wen Bin Chen
Keyword(s):  
Multiple Access ◽  
Multiple Access Interference ◽  
Optical Filters ◽  
Optical Cdma ◽  
Spectral Amplitude ◽  
Eye Diagram ◽  
Cdma Networks ◽  
Coding Method ◽  
Simulation Results ◽  
Spectral Amplitude Coding

This study analyzes and calculates unipolar and bipolar coded configurations of spectral-amplitude-coding optical division multiple access (SAC-OCDMA) systems by using analytic and simulated methods. The important feature of the SAC-OCDMA systems is that multiple access interference (MAI) can be eliminated by code sequences of a fixed in-phase cross-correlation value. This property can be effectively canceled by multiple access interference by using balance detection schemes. This study uses Walsh-Hadamard codes as signature codes for the unipolar and bipolar schemes. The coder and decoder structures are based on optical filters of fiber Bragg gratings (FBGs). The simulation results of unipolar/bipolar coding structures are first presented by commercial simulation obtained using OptiSystem software. The simulation results show that the bit error rate (BER) through use of the bipolar coding method is superior to the unipolar scheme, especially when the received effect power is large. The eye diagram also shows that the bipolar encoding structure exhibits a wider opening than the unipolar encoding structure.

Performance Analysis of 2-D Prime Codes Encoded Optical CDMA System

2019 ◽  
Vol 40 (4) ◽  
pp. 463-472
Author(s):  
Ankita Rani ◽  
Deepak Kedia
Keyword(s):  
Multiple Access ◽  
Electrical Power ◽  
Multiple Access Interference ◽  
Optical Cdma ◽  
Wavelength Division ◽  
High Data ◽  
Construction Methods ◽  
Data Rates ◽  
Improved Performance ◽  
Code Division Multiple

Abstract Optical code division multiple access (OCDMA) system provides highly secured transmission in addition to its capabilities to support asynchronous transmission and soft blocking. Two-dimensional OCDMA codes are chosen in this paper due to their high cardinality, good spectral efficiency and flexibility in their construction methods against direct sequence codes. This paper focuses on study of impact of multiple access interference (MAI) at high data rates for 2-D prime codesbased OCDMA system. It is shown that how the change in number of simultaneous users affects the transmission quality. Further, performance of the system is analysed in terms of bit error rate, received electrical power and eye openings. In addition, this paper also shows a comparative analysis of 2-D codes-based OCDMA system and wavelength division multiple access (WDMA) system in order to justify the improved performance of the proposed system. It is observed that the performance of 2-D OCDMA system is much better than WDMA system in terms of quality as well as security.

Unified KS-Code

2009 ◽  
pp. 1473-1479 ◽  
Author(s):  
M. K.A. Abdullah ◽  
S. A. Aljunid ◽  
M. D.A. Samad ◽  
S. B.A. Anas ◽  
R. K.Z. Sahbudin
Keyword(s):  
Multiple Access ◽  
Direct Detection ◽  
Multiple Access Interference ◽  
Optical Cdma ◽  
Spectral Amplitude ◽  
Service Guarantees ◽  
Narrow Bandwidth ◽  
Network Topologies ◽  
Spectral Amplitude Coding ◽  
Code Division Multiple

Many codes have been proposed for optical CDMA system as discussed in Svetislav, Mari, Zoran, Kosti, and Titlebaum (1993), Salehi (1989), Liu and Tsao (2002), Maric, Moreno, and Corrada (1996), Wei and Ghafouri-Shiraz (2002), and Prucnal, Santoro, and Ting (1986). Optical code division multiple access (OCDMA) has been recognized as one of the most important technologies for supporting many users in shared media simultaneous, and in some cases can increase the transmission capacity of an optical fiber. OCDMA is an exciting developments in short haul optical networking because it can support both wide and narrow bandwidth applications on the same network, it connects large number of asynchronous users with low latency and jitter, and permits quality of service guarantees to be managed at the physical layer, offers robust signal security and has simplified network topologies. However, for improperly designed codes, the maximum number of simultaneous users and the performance of the system can be seriously limited by the multiple access interference (MAI) or crosstalk from other users. Another issue in OCDMA is how the coding is implemented. The beginning idea of OCDMA was restricted in time domain, in which the encoding/decoding could not been fully utilized in optical domain. Therefore a new coding in OCDMA has been introduced based on spectral encoding (Kavehrad & Zaccarin, 1995; Pearce & Aazhang, 1994; Smith, Blaikie, & Taylor, 1998; Wei & Ghafouri-Shiraz, 2002). The system, called Optical Spectrum CDMA, or OS-CDMA, has the advantage of using inexpensive optical sources, and simple direct detection receivers. In this article with an emphasis on the Spectral Amplitude Coding scheme, a new code known as Khazani-Syed (KS) code is introduced.

Interferometric noise suppression by means of dispersion-imbalanced loop mirror over a wavelength range of 28 nm

2002 ◽  
Vol 14 (3) ◽  
pp. 417-419 ◽  
Author(s):  
Y.J. Chai ◽  
I.Y. Khrushchev ◽  
R.V. Penty ◽  
I.H. White
Keyword(s):  
Wavelength Range ◽  
Noise Suppression ◽  
Interferometric Noise ◽  
Loop Mirror ◽  
28 Nm

A Review on Successive Interference Cancellation Scheme Based on Optical CDMA Network

2014 ◽  
Vol 35 (4) ◽  
Author(s):  
N. Alsowaidi ◽  
T. Eltaif ◽  
M. R. Mokhtar
Keyword(s):  
Interference Cancellation ◽  
Multiple Access ◽  
Direct Detection ◽  
Multiple Access Interference ◽  
Successive Interference Cancellation ◽  
Optical Cdma ◽  
Spectral Amplitude ◽  
Cdma System ◽  
Spectral Amplitude Coding ◽  
Code Division Multiple

AbstractDue to various desirable features of optical code division multiple access (OCDMA), it is believed this technique once developed and commercially available will be an integral part of optical access networks. Optical CDMA system suffers from a problem called multiple access interference (MAI) which limits the number of active users, it occurs when number of active users share the same carriers. The aim of this paper is to review successive interference cancellation (SIC) scheme based on optical CDMA system. The paper also reviews the system performance in presence of shot noise, thermal noise, and phase–induced intensity noise (PIIN). A comprehensive review on the mathematical model of SIC scheme using direct detection (DS) and spectral amplitude coding (SAC) were presented in this article.

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