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Apart from efficient use of assigned spectral resources as a primary user, Cognitive Radio (CR) has the ability to act as a secondary user, utilizing available radio resources, which are not used by primary users for a certain period of time. This paper refers to mobile CR network management, based on multi-stage machine method. The article shows the idea of the Cognitive Manager (CM), consisting of three logical modules: Clustering (CL), Clusters Graph Coloring (CGC) and Supervisor (SP) with Sensing Client (SC). SP is responsible for management of all other cognitive manager blocks. This paper describes the SP structure and its cooperation with other CM modules. Prepared simulation scenarios take into account the propagation phenomena and presence of other users and jammers, that can use the same frequency channels as CR network. The events like lack of communication between nodes, bad links quality and presence of jamming, cause the appropriate reaction of SP. In such cases, SP performs analysis of current situation, and if necessary, it changes actual used frequency (color) using backup channels list, which is permanently updated. The presented idea has been implemented in the CORASMA (Cognitive Radio for dynamic Spectrum Management) simulator. |
