Date Added: Jun 2011
The sub-optimal exploitation of radio spectrum is widely accepted. Cognitive radio is a technology that aims to address this issue and improve the overall efficiency of radio spectrum utilization. However, this promising technology is far from being mature at present. In addition to theoretical research, experimentally-driven research is needed to convince industry and regulators of the benefits of cognitive radio. Several initiatives in this direction are taking place or are currently operational in both Europe and the United States. Most of them feature testbeds devoted to a specific radio access technology, network topology or application.