| Traditional WDM technology has some shortcomings such as fixed frequency grid and coarse service granularity which makes its poor capacity utilization and high cost. Elastic Optical Network(EON) has many obvious advantages such as high spectrum efficiency and flexibility, which is widely accepted as one of major development trends in optical networks. Routing and Spectrum Allocationn(RSA) is a key issue in EON. This thesis presents a systematical and comprehensive study on RSA algorithms in EON with theoreotical analysis and numerical simulations.Firstly, some fundamental principles and key technologies of EON are presented in this thesis. Baesd on the analysis of routing and spectrum allocation problem, this thesis focuses on the energy efficiency issue of RSA algorithms, especially. An improved energy aware routing and spectrum allocation(RA+EA-RSA) algorithm is proposed with considering the network energy consumption and available spectrum resources in the modulation format decision and spectrum allocation phase. The energy efficiency and blocking probability performance under different traffic load conditions have been demonstrated for different network topologies by simulations. Simulation results show that the improved algorithm can increase the energy efficiency and decrease the blocking probability, simultaneously. Under dynamic traffic conditions, fragmentation of the spectral resources reduces the spectrum efficiency, and degrades the blocking probability. To address this problem, this thesis proposes an improved fragmentation aware routing and spectrum allocation(FA-RSA) algorithm by considering the spectrum fragmentation in routing decision and spectrum allocation phase, which can utilize the spectrum fragmentation resources as far as possible. Simulation results show that compared with the traditional Dijkstra+FF and Dijkstra+RF algorithms, FA-RSA algorithm can significantly decrease the blocking probability and increase the spectrum efficiency. |
PDF Full Text Request