COOPERATIVE SPECTRUM ACCESS FOR DECENTRALIZED COGNITIVE RADIO SYSTEM

Cognitive radio (CR) is a promising technology available to that seeks the range and
efficiency of spectrum dependent services. Its system maps unused spectrum, and
arrange secondary user (SU) to operate within unoccupied license spectrum. The
implementation of CR system guarantees that there are no interferences to primary
user (PU) by prior observing and sensing the existing spectrum environment.
Spectrum sensing is the main issue ofCR system to prevent the harmful interference
to PU as a license user. However, practically detection performance is often
compromised with multipath fading, shadowing and uncertainty noises. In order to
minimize the impact of these issues, cooperative spectrum sensing and access is an
effective method to improve detection performance.