Aprovisionamento dinâmico de recursos em redes ópticas elásticas multiplexadas por divisão de espaço considerando limitações de camada física

Abstract

In elastic optical networks (EONs) employing weakly-coupled single-mode multi-core fibers (MCF), inter-core crosstalk (XT) can affect significantly the network performance, particularly when the number of cores and the path length increase. Hence, from the network perspective, the impairment-aware (IA) routing, spectrum and core assignment (RSCA) problem is an important research challenge of MCF-EONs. In this thesis, we propose a dynamic provisioning methodology that solves independently the IA-RSCA problem taking impairments physical layer into account. To achieve the XT impact minimization, we decompose the IA-RSCA problem into two subproblems: the IA routing sub-problem and the IA spectrum and core assignment (IA-SCA) sub-problem. For the routing solution, a precomputation method based on the k-shortest path is used, and a physical layer impairment verification phase is performed taking the required optical signal to noise ratio into account. For the IA-SCA sub-problem, the novel XT-aware greedy algorithm is proposed to minimize the XT impact on the MCF-EONs performance as follows: for each new connection, the level of detected XT power of the new connection and interfering connections relative to the XT power threshold of each connection is minimized on the average over all those connections. This minimization is achieved by choosing the core and frequency slot of the new connection. In order to take the spectral overlapping extension of the new and interfering connections into account in the detected XT power, a novel frequency slot overlapping index is introduced. The performance of the proposed algorithm is evaluated through computer simulations. The results show that the total blocking probability and network average utilization achieved by the proposed algorithm are better than the ones obtained by core prioritization, random and first-fit strategies, for different scenarios of XT level and spectrum fragmentation.