A system that identifies a number of secondary systems located in a first geographical area; identifies a primary resource available to be assigned to the secondary systems, the primary resource being a resource to which a primary system has a priority usage right; determines whether the number of secondary systems located in the first geographical area exceeds a predetermined threshold value; and limits a number of secondary systems to which the primary resource is assigned when it is determined that the number of secondary systems located in the first geographical area exceeds the predetermined threshold value.