Research on routing and wavelength/subcarrier assignment algorithm based on layered-graph model in optical satellite networks

In optical satellite networks with multi-wavelengths and multi-subcarriers, two-level switching mode replace single wavelength switching, achieving better flexibility and network performance with its disadvantages of more complex routing and network resource allocation. Based on subcarrier layered-graph (SL-G), a novel dynamic routing and wavelength/subcarrier assignment (RWSA) algorithm is proposed to find the shortest path with limited costs in the corresponding layered-graph. By defining different edge cost functions in SL-G, centralized resource allocation strategy and decentralized resource allocation strategy in dynamic RWSA are analysed for optical satellite networks with different types of constellations. Simulation results demonstrate that, no matter whether optical satellite networks has single constellation with uniform wavelength distribution or hybrid constellations with non-uniform wavelength distribution, the proposed RWSA algorithms are superior to traditional routing and wavelength assignment algorithms with lower network blocking probability.