Variable Weight Optical Orthogonal Codes for Cdma Networks with Multiple Performance Requirements

An optical orthogonal code (OOC) is a collection of binary sequences with good auto- and cross-correlation properties; they were defined by Salehi and others as a means of obtaining code division multiple access (CDMA) on fiber optic networks. Up to now all work on OOC's have assumed that the weight of each codeword is the same. In this paper we develop bounds on the size of OOC'S when this assumption is removed. In addition, we demonstrate construction techniques for building such "variable weight" OOC'S. The results demonstrate that it is possible to assign codewords with different weights among the users. Changing the weight of a user's signature sequence affects that user's performance; therefore this approach is useful for CDMA fiber optic networks with multiule performance requirements among the users.