ABSTRACT
Radio spectrum refers to a range of frequencies over which electromagnetic signals can be transmitted. It is an essential and finite resource to provide various services, such as mobile telecommunications, global positioning system (GPS) localization, broadcasting, aeronautical and marine communications, radar detection, and so on. An increasing number of services are using radio spectrum, and the spectrum demands of each service have increased enormously, such as the growing use of mobile phones and GPS devices. Therefore, as a public resource, it is used to obtain the greatest economic benefits and to serve the maximum number of users. And efficient spectrum management is needed to satisfy the tremendous spectrum demand on the finite radio spectrum.
