Two-Dimensional Optical Orthogonal Codes for Fiber-Optic CDMA Networks

Shivaleela, ES and Selvarajan, A and Srinivas, T (2005) Two-Dimensional Optical Orthogonal Codes for Fiber-Optic CDMA Networks. In: Journal of Lightwave Technology, 23 (2). pp. 647-654.

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Abstract

Several constructions of two-dimensional (2-D) codes have been proposed to overcome the drawbacks of nonlinear effects in large spread sequences of one-dimensional (1-D) unipolar codes in fiber-optic code-division multiple-access (FO-CDMA) networks. Wavelength-time (W/T)encoding of the 2-D codes is practical in FO-CDMA networks. W/T codes reported so far can be classified mainly into two types: 1) hybridcodes, where one type of sequence is crossed with another to improve the cardinality and correlation properties and 2) conversion of 1-Dsequences to 2-D codes to reduce the "timelike" property. This paper describes the basic principles of a new family of wavelength/time multiple-pulses-per-row (W/T MPR) codes, for incoherent FO-CDMA networks, which have good cardinality, spectral efficiency, and minimal cross correlation values. In addition, an expression for the upperbound on the cardinality of W/T MPR codes is derived. Another feature of the W/T MPR codes is that the aspect ratio can be varied by a trade off between wavelength and temporal lengths. The correlation properties of W/T MPR codes are verified by simulation using Matlab.For given wavelength x time dimensions, various W/T codes, whose cardinalities are known, are compared, and it is shown that the W/T MPRfamily of codes have better cardinality and spectral efficiency than the other W/T codes. Performance analysis of the W/T MPR codes and their limiting cases is carried out for various parameter variations such as the dimensions of wavelength, time, and weight of the code.

Item Type:	Journal Article
Publication:	Journal of Lightwave Technology
Publisher:	Institute of Electrical and Electronics Engineers Inc.
Additional Information:	©2005 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Keywords:	Fiber-optic communication;incoherent optical communications;optical-code-division multiple access;wavelength/time codes
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering
Date Deposited:	21 Mar 2005
Last Modified:	19 Sep 2010 04:18
URI:	http://eprints.iisc.ac.in/id/eprint/2959

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