Cooperative spectrum sensing with collaborative users using individual sensing credibility for cognitive radio network

Cognitive radio (CR) has been considered as one of the promising next-generation communication systems owning to its ability of sensing and making use of vacant channels that are currently unused by licensed users. Reliable spectrum sensing of licensed users is required for CR network to minimize interference to licensed users. However, an individual CR user may find it difficult to reliably detect the activity status of licensed users due to fading and shadowing effects of the channel. In this paper, we propose a cooperative spectrum sensing scheme for collaborative users in which the sensing credibility of each individual user is utilized to improve local and global sensing performance, and reduce the number of reports transmitted through the control channel between CR users and the fusion center (FC). Using this method, few CR users who satisfy the credibility thresholds will transmit their local decisions to the FC one by one according to the states order of their credibility. That is, the CR user with higher reliability will transmit local decision sooner and others with less reliability can use this sensing information to update their local decisions. Finally, all local decisions received at the FC are combined into a global decision using the Chair - Varshney data fusion rule.