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Journal Article•DOI•

A new family of optical code sequences for spectral-amplitude-coding optical CDMA systems

Syed Alwee Aljunid1, Mahamod Ismail2, Abdul Rahman Ramli1, Borhanuddin Mohd Ali1, Mohamad Khazani Abdullah1 •
Universiti Putra Malaysia1, National University of Malaysia2
27 Sep 2004-IEEE Photonics Technology Letters (IEEE)-Vol. 16, Iss: 10, pp 2383-2385
TL;DR: Modified double-weight (MDW) code is shown here to provide a much better performance compared to Hadamard and modified frequency-hopping codes.
Abstract: A new code structure for spectral-amplitude-coding optical code-division multiple-access system based on double-weight (DW) code families is proposed. The DW code has a fixed weight of two. By using a mapping technique, codes that have a larger number of weights can be developed. Modified double-weight (MDW) code is a DW code family variation that has variable weights of greater than two. The newly proposed code possesses ideal cross-correlation properties and exists for every natural number n. Based on theoretical analysis and simulation, MDW code is shown here to provide a much better performance compared to Hadamard and modified frequency-hopping codes.

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A new family of optical code sequences for spectral-amplitude-coding optical CDMA
systems
ABSTRACT
A new code structure for spectral-amplitude-coding optical code-division multiple-access
system based on double-weight (DW) code families is proposed. The DW code has a fixed
weight of two. By using a mapping technique, codes that have a larger number of weights can
be developed. Modified double-weight (MDW) code is a DW code family variation that has
variable weights of greater than two. The newly proposed code possesses ideal cross-
correlation properties and exists for every natural number n. Based on theoretical analysis and
simulation, MDW code is shown here to provide a much better performance compared to
Hadamard and modified frequency-hopping codes.
Keyword: Cross correlation; Double-weight (DW) code; Modified double-weight (MDW)
code; optical spectrum code-division multiple-access (OSCDMA)
Citations
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Journal Article•DOI•
Development of a new code family based on SAC-OCDMA system with large cardinality for OCDMA network

[...]

Thanaa Hussein Abd1, Syed Alwee Aljunid1, Hilal A. Fadhil1, Rasheed Ahmad1, Naufal M. Saad2 •
Universiti Malaysia Perlis1, Petronas2
01 Jul 2011-Optical Fiber Technology
TL;DR: Simulation results show this new Multi-Diagonal code for Spectral Amplitude – Coding Optical Code Division Multiple Access to provide a much better performance compared to Modified Quadratic Congruence (MQC) code and Random Diagonal (RD) code.

100 citations

Journal Article•DOI•
Performance of random diagonal code for OCDMA systems using new spectral direct detection technique

[...]

Hilal A. Fadhil1, Syed Alwee Aljunid1, R. B. Ahmad1•
Universiti Malaysia Perlis1
01 Jun 2009-Optical Fiber Technology
TL;DR: It is shown that the proposed new spectral direct detection technique utilizing RD code considerably improves the performance compared with the conventional SAC complementary subtraction technique.

91 citations

Journal Article•DOI•
Performance of OCDMA systems with new spectral direct detection (SDD) technique using enhanced double weight (EDW) code

[...]

Mohamad Khazani Abdullah1, Feras N. Hasoon, Syed Alwee Aljunid2, Sahbudin Shaari•
Universiti Putra Malaysia1, Universiti Malaysia Perlis2
15 Sep 2008-Optics Communications
TL;DR: The theoretical and simulation results show that the proposed new spectral direct detection technique improves the performance compared to the conventional complementary subtraction technique.

64 citations

Journal Article•DOI•
Code Family for Modified Spectral-Amplitude-Coding OCDMA Systems and Performance Analysis

[...]

Mohammad Noshad1, Kambiz Jamshidi2•
Sharif University of Technology1, Deutsche Telekom2
01 Jun 2010-IEEE\/OSA Journal of Optical Communications and Networking
TL;DR: A novel family of codes for modified spectral-amplitude-coding optical code division multiple access (SAC-OCDMA) is introduced and the number of users can be extended without any essential changes in the previous transmitters.
Abstract: A novel family of codes for modified spectral-amplitude-coding optical code division multiple access (SAC-OCDMA) is introduced. The proposed codes exist for more processing gains than the previously reported codes do. In the network using these codes, the number of users can be extended without any essential changes in the previous transmitters. In this study, we propose a construction method for these codes and compare their performance with previously reported codes.

57 citations

Journal Article•DOI•
Optical domain service differentiation using spectral-amplitude-coding

[...]

S. B. Ahmad Anas1, S. B. Ahmad Anas2, Mohamad Khazani Abdullah2, Makhfudzah Mokhtar2, Syed Alwee Aljunid3, Stuart D. Walker1 •
University of Essex1, Universiti Putra Malaysia2, Universiti Malaysia Perlis3
01 Jan 2009-Optical Fiber Technology
TL;DR: The results characterizing the bit-error-rate (BER) with respect to the total number of active users show that KS offers a significantly improved performance over the previous reported techniques by accommodating additional 30 users with shorter code length and smaller code weight at BER of 10−9.

48 citations

References
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Journal Article•DOI•
Code division multiple-access techniques in optical fiber networks. I. Fundamental principles

[...]

Jawad A. Salehi
01 Aug 1989-IEEE Transactions on Communications
TL;DR: An examination is made of fiber-optic code-division multiple-access (FO-CDMA), a technique in which low information data rates are mapped into very-high-rate address codes (signature sequences) for the purpose of achieving random, asynchronous communications free of network control, among many users.
Abstract: An examination is made of fiber-optic code-division multiple-access (FO-CDMA), a technique in which low information data rates are mapped into very-high-rate address codes (signature sequences) for the purpose of achieving random, asynchronous communications free of network control, among many users. The need for a special class of signature sequences to achieve the multiple-access capability using fiber-optic signal processing techniques is discussed. A class of signature sequences called optical orthogonal codes (OOCs) that provide the auto- and cross-correlation properties required for FO-CDMA is introduced and used in an experiment to show the principles of FO-CDMA. The experiment demonstrates the auto- and cross-correlation properties of the codes. The concept of optical disk patterns, an equivalent way of representing the OOCs, is introduced. The patterns are used to derive the probability density functions associated with any two interfering OOCs. A detailed study of different interference patterns is presented, and the strongest and the weakest interference patterns are determined. >

1,474 citations

"A new family of optical code sequen..." refers background in this paper

  • ...Many codes have been proposed for OSCDMA such as optical orthogonal codes (OOCs) [4], prime codes, and modified frequency-hopping (MFH) codes [5]....

    [...]

Journal Article•DOI•
Spread spectrum fiber-optic local area network using optical processing

[...]

Paul R. Prucnal1, M. Santoro2, Ting Fan•
Princeton University1, Columbia University2
01 May 1986-Journal of Lightwave Technology
Abstract: Spread spectrum code division multiple access (CDMA) allows asynchronous multiple access to a local area network (LAN) with no waiting. The additional bandwidth required by spread spectrum can be accommodated by using a fiber-optic channel and incoherent optical signal processing. New CDMA sequences are designed specifically for optical processing. It is shown that increasing the number of chips per bit, by using optical processing, allows an increase in capacity of a CDMA LAN. An experiment is performed demonstrating the performance of an optical CDMA LAN, operating at 100 Mbd with three users.

768 citations

"A new family of optical code sequen..." refers background in this paper

  • ...The advantages of OSCDMA technique over other multiplexing techniques such as time-division multiple-access and frequency-division multiple-access are numerous [3], [8]....

    [...]

Journal Article•DOI•
Optical code-division-multiplexed systems based on spectral encoding of noncoherent sources

[...]

Mohsen Kavehrad1, D. Zaccarin2•
Ottawa University1, bell northern research2
01 Mar 1995-Journal of Lightwave Technology
TL;DR: This work presents a new category of optical CDMA systems which work based on spectral encoding, that the authors refer to as frequency-encoded CDMA (FE-CDMA) systems, which are based on encoding noncoherent broadband sources.
Abstract: Presents a new category of optical CDMA systems which work based on spectral encoding. In such systems, that the authors refer to as frequency-encoded CDMA (FE-CDMA) systems, the coding is done in the frequency domain while in the usual CDMA systems the code multiplies the modulation signal in the time domain. They present a new type of FE-CDMA system, based on encoding noncoherent broadband sources. They discuss the advantages of the system compared to other optical CDMA systems and present its performance. They show that very efficient, low-cost, CDMA systems can be obtained with an aggregate throughput of many gigabits per second. Also, for this system, the spreading gain of CDMA is independent of the modulation bandwidth. Hence, the system can accommodate variable bit rates, naturally. >

416 citations

Additional excerpts

  • ...A similar approach has been used in a previous report [7]....

    [...]

Journal Article•DOI•
Performance enhancement of spectral-amplitude-coding optical CDMA using pulse-position modulation

[...]

E.D.J. Smith1, Richard J. Blaikie1, Desmond P. Taylor1•
University of Canterbury1
01 Sep 1998-IEEE Transactions on Communications
TL;DR: The interference-limited performance of the PPM-OCDMA system is found to be superior to that of the original system when the number of simultaneous users is of the order of thePPM word length or larger.
Abstract: Spectral-amplitude-coding optical code-division multiple-access (OCDMA) systems are limited by interference between incoherent sources. A detailed analysis of this limit for a system with a balanced receiver is presented. Additional pulse-position modulation (PPM) coding is proposed as a method to improve the system performance beyond this limit. A simple and robust PPM decoding structure is proposed, and the performance analysis of the whole PPM-OCDMA system is presented. The interference-limited performance of the PPM-OCDMA system is found to be superior to that of the original system when the number of simultaneous users is of the order of the PPM word length or larger. In particular, for a PPM word length of two, an increase in spectral efficiency of up to 100% is possible with no change in the signaling rate, data rate, or bit-error rate (BER).

329 citations

Journal Article•DOI•
Codes for spectral-amplitude-coding optical CDMA systems

[...]

Zou Wei1, Hooshang Ghafouri-Shiraz1•
Nanyang Technological University1
10 Dec 2002-Journal of Lightwave Technology
TL;DR: It has been shown that the system performance can be improved significantly by using codes with ideal in-phase CC instead of the Hadamard code, and these codes can be used in the synchronous optical CDMA systems for multiuser interference cancellation.
Abstract: Codes with ideal in-phase cross correlation (CC) are required in spectral-amplitude-coding optical code-division multiple-access (CDMA) systems since these codes eliminate multiuser interference and also suppress the effect of phase-induced intensity noise. However, little research work has been done on such codes although codes with ideal CC have been studied for many years. In a paper by Zhou et al. (2000), such a code has been introduced, but no clear construction method has been presented. In this paper, we first review the construction method of this old code and then construct two new codes with ideal in-phase CC in algebraic ways. Both of the proposed new codes are obtained by modifying former codes with ideal CC. It has been shown that the system performance can be improved significantly by using codes with ideal in-phase CC instead of the Hadamard code. These codes can also be used in the synchronous optical CDMA systems for multiuser interference cancellation.

185 citations

"A new family of optical code sequen..." refers background in this paper

  • ...Many codes have been proposed for OSCDMA such as optical orthogonal codes (OOCs) [4], prime codes, and modified frequency-hopping (MFH) codes [5]....

    [...]

  • ...In [5], for code sequence and , the cross-correlation is given by...

    [...]

Related Papers (5)
Modified quadratic congruence codes for fiber Bragg-grating-based spectral-amplitude-coding optical CDMA systems

[...]

01 Sep 2001-Journal of Lightwave Technology
Zou Wei, Hossam M. H. Shalaby, Hooshang Ghafouri-Shiraz
Codes for spectral-amplitude-coding optical CDMA systems

[...]

10 Dec 2002-Journal of Lightwave Technology
Zou Wei, Hooshang Ghafouri-Shiraz
Code division multiple-access techniques in optical fiber networks. I. Fundamental principles

[...]

01 Aug 1989-IEEE Transactions on Communications
Jawad A. Salehi
Performance enhancement of spectral-amplitude-coding optical CDMA using pulse-position modulation

[...]

01 Sep 1998-IEEE Transactions on Communications
E.D.J. Smith, Richard J. Blaikie, Desmond P. Taylor
Optical code-division-multiplexed systems based on spectral encoding of noncoherent sources

[...]

01 Mar 1995-Journal of Lightwave Technology
Mohsen Kavehrad, D. Zaccarin
Frequently Asked Questions (1)
Q1. What contributions have the authors mentioned in the paper "A new family of optical code sequences for spectral-amplitude-coding optical cdma systems" ?

In this paper, a new code structure for spectral-amplitude-coding optical code-division multiple access system based on double-weight ( DW ) code families is proposed.