Embodiments assign shared spectrum resources to access points. Embodiments group the access points into coexistence groups of access points, and generate a vertex graph including vertices that each represent one of the coexistence groups, where an edge connecting a pair of vertices in the vertex graph represents an overlap between coverage contours of a pair of coexistence groups represented by the pair of vertices, and the edge is assigned a weight that is proportional to the overlap as compared to other overlaps between coverage contours of other pairs of coexistence groups. Embodiments generate at least one vertex-colored graph by assigning a color to each vertex in the vertex graph, group the coexistence groups into groups of coexistence groups based on their corresponding assigned colors in the at least one vertex-colored graph, and map shared spectrum transmit frequencies to the groups of coexistence groups.