Channel assignment and reallocation algorithms for cognitive radio systems

Wireless communication services have been increasing rapidly and this progress has caused a shortage in frequency resources. Cognitive radio technology is expected to enable frequency resources to be used more efficiently. When several wireless communication systems simultaneously use cognitive radio technology, the priority level of each system for frequency use is set and the frequency resource is shared between the systems according to the priority level. In cognitive radio systems, algorithms for channel assignment to access points (AP) have to manage priority levels in frequency use. The conventional dynamic channel assignment (DCA) technology cannot be used in cognitive radio systems without modification since the technology does not have the scheme to manage priority level in the frequency use. We have proposed methods of channel assignment and channel reallocation that are suitable for cognitive radio systems and evaluated our proposed methods using a computer simulation. In addition, we have proposed a new frequency utilization efficiency criterion for cognitive radio systems.