Impairment Aware Routing and Wavelength Assignment model employing binary logic operators

Abstract

Effective quality monitoring per wavelength channel is indispensable to modern high speed transparent DWDM systems. Besides linear and nonlinear degradation, the optical impairments also depend upon wavelength channel used along with the state of other channels at a given time. In this paper we have proposed a mixed integer linear programming(MILP) model for solving routing and wavelength assignment problem that uses logic operators to include impairments caused by the state of the neighbouring channels. Further the optical impairment applicable at each wavelength channel is distinct and under given condition each wavelength channel experiences different deterioration. We compare it with existing mathematical models in which strategic spectrum spacing is employed to mitigate the effect of impairments. It has been found that in the former method, Quality of Transmission (QoT) is maintained at all cost. The latter method though converges much faster but due to non-utilization of certain wavelength channels the overall traffic carrying capacity of WDM system get reduced.