A solution to the MCSP problem considering physical layer degradations in transparent optical networks
In all-optical networks, the physical layer impairments cause a degradation in the transmitted signal. Sometimes, the degradation causes an inadmissible Optical Signal to Noise Ratio (OSNR), which is translated into blocking due to low quality of transmission. The Impairment Aware -- Routing and Wavelength Assignment (IA-RWA) should choose the route and wavelength considering the physical layer impairments. The Choice of the Best Combination among M Combinations of Shortest Paths (MCSP) problem consists of choosing the best of the shortest paths for a network topology aiming to reduce the blocking probability. This paper presents a pioneer study of the MCSPs problem assuming Amplified Spontaneous Emission (ASE), co-wavelength crosstalk, self-wavelength crosstalk, neighbor wavelength crosstalk, Polarization Mode Dispersion (PMD) and attenuations caused by fiber and devices. In this context, we propose a new routing algorithm that aims to resolve the MCSP problem considering the physical impairments.
OSNR model to consider physical layer impairments in transparent optical networks
We propose a model that considers several physical impairments in all-optical networks based on optical signal-to-noise degradation. Our model considers the gain saturation effect and amplified spontaneous emission depletion in optical amplifiers, coherent crosstalk in optical switches, and four-wave mixing in transmission fibers. We apply our model to investigate the impact of different physical impairments on the performance of all-optical networks. The simulation results show the impact of each impairment on network performance in terms of blocking probability as a function of device parameters. We also apply the model as a metric for impairment-constraint routing in all-optical networks. We show that our proposed routing and wavelength assignment algorithm outperforms two common approaches.
Cross Layer Routing in Transparent Optical Networks
New algorithmically simplified WRA that incorporate physical layer criteria in the path establishment procedure are suggested and applied in the Deutsche-Telecom network. Their blocking performance superiority and physical performance guarantee are discussed.