A new wavelength assignment method for minimal wavelength conversions in WDM networks

In multihop systems of wavelength division multiplexing (WDM) networks, wavelength conversion is required at the conjunction of two lightpaths if they use different wavelengths. We consider the problem of assigning wavelengths to the lightpaths by using a limited number of wavelengths, so that the overall number of wavelength conversions in the whole system is minimal. The problem is formulated as a maximum clique cover problem. An approximation algorithm is proposed to solve it. Our proposed theory also illustrates the tradeoff relationship between the number of wavelengths and the number of conversions in the system.