Orthogonal en/decoders for truly asynchronous spectral amplitude encoded OCDMA

In this paper, theoretical results are presented on the modular construction of tree and cascade encoders/decoders of any size for truly asynchronous and orthogonal spectral amplitude encoded OCDMA. Three modular building blocksare proposed and described in detail. The tree structure is introduced that enables parallel code processing with a single device. The orthogonality of the code set is evaluated whereafter a revised construction method is proposed. Analysis and simulation confirm that a tree constructed via this method is orthogonal