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 are used 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 consider codes when this assumption as removed. We develop bounds on the size of such “variable weight” OOC´s and demonstrate construction techniques for building them. Furthermore, we provide an analysis to the performance of variable weight, OOC´s in a CDMA network. 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 multiple performance requirements among the users