Accounting for PMD Temporal Correlation During Lightpath Set Up in Transparent Optical Networks

Abstract

In transparent optical networks, the signal transmission is degraded by optical layer physical impairments. Therefore, lightpaths may be blocked due to unacceptable quality of transmission (QoT). Among physical impairments, polarization mode dispersion (PMD) is a detrimental effect which has stochastic characteristics. Moreover, PMD depends on time-variant factors, such as the temperature and the fiber stress. When implementing a dynamic GMPLS-controlled transparent optical network, the GMPLS protocol suite must take into account physical impairment information in order to establish lightpaths while guaranteeing the required QoT. In the literature, solutions for QoT-aware GMPLS control plane commonly consider that the effects of PMD on QoT are not detrimental when the average differential group delay (DGD) does not exceed a threshold. However, even with a high average DGD, it may happen that the instantaneous DGD is not detrimental. Additionally, given PMD temporal correlation properties, once that the instantaneous DGD is not detrimental, it continues to be not detrimental within considerable time ranges. Therefore, more accurate models can be implemented in the GMPLS control plane to account for PMD. In this paper we propose a novel lightpath provisioning scheme based on a PMD prediction model which accounts for PMD temporal correlation properties. The proposed PMD-temporal-correlation (PTC) based lightpath provisioning scheme is compared with a scheme based on a classical PMD model. Simulation results show that PTC scheme significantly reduces the lightpath blocking probability with respect to the classical scheme. Moreover, PTC demonstrates that, by considering PMD temporal correlation, the transparency domain size can be increased, since paths that would be rejected by a classical model can be actually accepted within specific time ranges.

Signaling-Based Joint Selection of Wavelengths and Regenerator Points in GMPLS-Controlled WSONs

“…RAO contains the information of the available regenerators along the path, whereas RO contains the set of nodes designated to be regeneration points. Without loss of generality, it is assumed that QoT is guaranteed by limiting the maximum all-optical reach, referred to as maximum regeneration span [8].…”