Capacity limits introduced by data fusion on cooperative spectrum sensing under correlated environments

Spectrum sensing, the cornerstone of the Cognitive Radio paradigm, has been the focus of intensive research, from which the main conclusion was that its performance can be greatly enhanced through the use of cooperative sensing schemes. In this paper we analyze the performance of a cooperative spectrum sensing scheme, by measuring the perceived capacity limits introduced by the use of data fusion on cooperative sensing schemes. The analysis is supported by evaluation metrics which account for the perceived capacity limits. The analysis is performed along the data fusion chain, comparing several scenarios encompassing different degree of environment correlation between the cluster nodes, number of cluster nodes and sensed channel occupation statistics. Through this study we motivate that to maximize the perceived capacity by the cooperative spectrum sensing, the use of data fusion needs to be performed in a fractioned way, i.e. the that fusion must be done between subsets of the nodes in a cluster.