Sparse-partial wavelength conversion: Converter placement and wavelength assignment

Wavelength conversion has been shown as one of the key techniques to improve blocking performance in a wavelength-routed all-optical WDM network. Given that wavelength converters nowadays remain very expensive, how to make effective use of a limited number of wavelength converters becomes an important issue. In this paper, we present and analyze the Sparse-Partial Wavelength Conversion (SPWC) network architecture, which has the inherent flexibility that can facilitate network carriers to upgrade the legacy optical backbone to support wavelength conversion. We explore the efficiency of partial wavelength conversion and demonstrate that SPWC architecture can significantly reduce the number of wavelength converters, yet achieve excellent blocking performance with a proper wavelength converter placement scheme. We also propose a wavelength assignment scheme called Minimum Converter Allocation (MCA), which can further improve the utilization of the wavelength converters. Simulation results indicate that, with the proposed MCA wavelength assignment algorithm, the performance of a wavelength-routed WDM network with only 1%-5% of wavelength conversion capability is very close to that with Full-Complete Wavelength Conversion capability.