Efficient frequency spectrum sharing between at least one incumbent communication system(s) (102, 152) and at least one cognitive radio (CR) system (105) is provided. The incumbent system's system parameters and CR system's operational requirements are copied to a mirrored database (106B). The mirrored database (106B) is controlled by a either a central authority (108) or a database manager having delegated authority (508). The mirrored database (106B) is accessed by the CR system (105). The mirrored database (106B) can be modified and updated by the central authority (108) or delegated database manager (508) to correct for interference detected in the incumbent system caused (152) by the cognitive radio system (105). The cognitive radio system (105) utilizes the updated mirrored database (106B) to avoid interfering with the incumbent system (102, 152) to determine CR system operating parameters thus enhancing the ability to share spectrum.