Opportunistic Spectral Reuse in Cellular Systems

Cognitive radio is a key enabling technology of dynamic spectrum access for exploiting unused spectrum resources. This article focuses on modeling the opportunity for cellular systems which have the greatest spectrum scarcity problem. A system model is introduced for analyzing the opportunistic bandwidth within a cellular network through a spatial evaluation of the resources used by the primary and available to the secondary systems. Towards this purpose, two metrics are introduced signifying the spatial coherence of resources: the region of interference and the region of communications. Our results suggest significant underutilized resources that can be scavenged through secondary users to greatly improve the spectral efficiency of cellular networks.