RWA algorithm design and performance analysis for all-optical networks subject to physical impairments.

摘要

Thanks to the rapid development of optical signal processing functions for fiber communication systems, and novel routing techniques and switching node architectures, highly flexible and transparent so-called "wavelength routed all-optical network" solutions have emerged. All-optical networks eliminate the restrictions incurred by periodic electronic regeneration, as signals remain in the optical domain from end-to-end through a lightpath.; As an optical signal propagates along a lightpath to its destination in wavelength-routed optical networks, the signal's quality of transmission is degraded by physical impairments. Consequently, the signal's bit error rate at the destination's receiver might become unacceptably high. Thus optical fiber components and intermediate switching nodes can be the dominant reason calls are blocked in networks. Moreover, estimating the impact of physical impairments on the quality of a lightpath before provisioning it can cause a significant delay, which also affects the performance of networks.; In this dissertation, we provide a general mathematical formulation to the optimal routing and wavelength assignment in impaired optical networks. Several dominant degradations from the physical layer are exemplified and incorporated in the general formulation. Realizing that routing algorithms and wavelength assignment algorithms can both be powerful tools used to mitigate the effect of physical impairments, we study the problem of designing efficiently routing and wavelength assignment algorithms in all-optical networks with physical impairments. Several adaptive routing policies accounting for the quality of transmission in optical networks are proposed to efficiently and intelligently find a feasible lightpath. In particular, we propose using the impairments variance along the route as a selection criterion. In addition, several spectrum allocation techniques are presented to alleviate physical impairments and also decrease the processing delay due to the QoT estimation. To thoroughly understand the RWAs and evaluate their performance incorporating multiple physical layer impairments, we present an analytical technique and compare it to simulation results we are able to predict the network behavior correctly on various network topologies.; We then investigate the impact of processing delay induced from QoT estimation. Simulations presented show that our design successfully remove not only part of the physical degradation but also decrease the delay due to QoT estimation.