Master of Science in Electrical Engineering (MSEE)


Electrical and Computer Engineering

Document Type



Recent years witnessed tremendous increase in data traffic as new Internet applications were launched. Optical networks employing recent technologies such as DWDM and EDFA`s emerged as the most prominent and most promising solutions in terms of their ability to keep with the demand on bandwidth. However for a class of applications bandwidth is not the only important requirement, These applications require efficient multicast operations. They include data bases, audio/video conferencing, distributed computing etc. Multicasting in the optical domain however has its own unique set of problems. First, an optical signal can be split among the outputs of a node but the power due to splitting can be significantly reduced. Second, the hardware for split nodes is relatively expensive and therefore we cannot afford to employ it at every node. Third, there are other sources of losses such as attenuation losses and multiplexing /de-multiplexing losses. This thesis deals with the important issue of Power Efficient multicast in WDM optical networks. We report three new algorithms for constructing power efficient multicast trees and forests. Our algorithms are the first to take into account all possible sources of power losses while constructing the trees. We utilize the techniques of backtracking and tree pruning judiciously to achieve very power efficient multicast trees. The first two algorithms use modified versions of the shortest path heuristic to build the tree. The third algorithm however, uses a novel concept and considers power at every tree building step. In this algorithm, the order of inclusion of destination nodes into the tree is based on the power distribution in the tree and not distance. All three algorithms prune the trees if the power levels at the destinations are not acceptable. The performance of these three algorithms under several constraints is studied on several irregular topologies. All three algorithms reported in this work produce significant improvements in signal strength at the set of destinations over the existing multicast algorithms. Numerical results show that our third algorithm outperforms the first two algorithms as well as the existing multicasting algorithms.



Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Ahmed El-Amawy