Research On Dynamic Routing And Wavelength Assignment Algorithm With Impairment Aware Issue

Optical signals will suffer different physical impairment while transferring along the lightpath inoptical networks such as chromatic dispersion, amplifier caused noise, non-linear effect andcrosstalk, etc. All these impairments can accumulate along the lightpath and bring significant signaldegradations. It is important to consider these impairments and the corresponding degradations inthe routing and wavelength assignment (RWA) algorithm to provide quality of service (QoS). Thisthesis gives a comprehensive and in-depth research on impairment aware RWA algorithm withtheoretical analysis and numerical simulations.Firstly, this thesis presents a brief introduction of physical layer impairments in optical networks.An improved impairment aware RWA (IA-QRWA) algorithm is proposed based on the theoreticalanalysis of different impairment mechanism. The improved algorithm introduced physical linkimpairment factor into traditional transfer probability in ant colony algorithm, by which ants willselect next hop with better physical impairment performance. Theoretical analysis and simulationresults show that the improved algorithm has significant improvement on system blockingprobability and resource utilization efficiency comparing with traditional shorting path (SP)algorithm.