Cognitive Radio Technology: System Evolution

Cognitive Radio is a novel method of radio communication which enables more efficient use of the frequency spectrum. This efficiency is achieved by dynamically allocating frequency bands within the spectrum to different users. Within the field of Cognitive Radio, many different aspects of the system must be considered in order to achieve an optimal system. This includes methods for sensing whether the spectrum is available, sensing which channel is best for use, determining the time required to transmit data, and determining protocols which ensure all users achieve an adequate quality of service. This paper reviews a section of current topics in Cognitive Radio research on how cognition is used to make optimal channel selection. Paper compares various methods and identifies significance of various options and their efficiencies.