Investigation On Optimal Placement Of Wavelength Converters In DWDM Optical Networks

Wavelength Conversion (WC) is very important function in all-optical DWDM (Dense Wavelength Division Multiplexing) network for its abilities in wavelength reusing, avoiding wavelength blocking and decentralizing network management. Sponsored by national 863 project and Wuhan technology innovation project, the optimal placement of wavelength converter in DWDM optical networks is comprehensive investigated in this thesis. The main achievements and conclusions are listed as follows: (1) Researches on all-optical wavelength converter and its applications in all-optical networks are reviewed; the effect on the performance of the DWDM networks by optimal placing wavelength converter is discussed. (2) The analysis models for DWDM optical networks reported in literatures are summarized. Two primary models of blocking probability—load dependent and load independent model are studied. The blocking probability performance for DWDM networks with or without wavelength converters are analyzed based on the load dependent model. (3) Based on shortest path routing and random wavelength assignment models, the ordinary Floyd and Dijkstra algorithm is improved in considering the load balance. The simulation results for real wavelength routing network show that the blocking probability could be improved by 20% when the load balance is considered in the routing algorithm (4) Optimal placement problems in the bus and ring topology network are theoretical demonstrated, and results would be helpful to optimize optical network topology. For optical networks with arbitrary topology, four heuristic algorithms are presented to achieve optimal wavelength converter placement. Results show that combing the load balance model with these heuristic algorithms could reduce blocking probability.