Spectrum Optimization in Cognitive Satellite Networks with Graph Coloring Method

Cognitive satellite networks can enhance spectrum efficiency by enabling satellite networks to dynamically share idle spectrum with terrestrial networks. However, when taking into consideration the inter-cell or internet interferences in various application circumstances, dynamic spectrum optimization in cognitive satellite networks remains challenging due to the diversified QoS demands of secondary terrestrial users. To address this issue, this paper proposes an efficient spectrum allocation algorithm which is based on graph coloring technique and combined with analytic hierarchy process so as to meet the requirements of dynamic spectrum allocation to secondary terrestrial users with diversified QoS demands and yet without causing severe inference to primary satellite users. In this paper, we combine graph coloring algorithm and analytic hierarchy process so as to assign the heterogeneous spectrum bands to secondary users in an orderly manner. The method of graph coloring is applied to control obvious interference caused by the secondary users. We also provide numerical results to evaluate the impacts of different parameter settings on the performances of the proposed solution.