Cooperative heterogeneous framework for spectrum harvesting in cognitive cellular network

With the proliferation of mobile devices and emerging data-hungry applications, mobile data has been increasing dramatically. To accommodate massive mobile data, the cellular network has been straining to meet the need due to the scarcity of spectrum. As a promising technology, cognitive radio can be leveraged by the cellular network to harvest spectrum holes on demand. By employing cognitive radio, the cellular network becomes a cognitive cellular network. In this article, we first provide an overview of the cognitive cellular network, including the network architecture and main applications. Then existing spectrum harvesting approaches are reviewed, and the limitations are identified. To better explore spectrum access opportunities, three types of cooperation-based approaches are introduced for different scenarios, based on which an integrated cooperative framework is devised to fully harvest spectrum holes. Simulation results are provided to evaluate the performance of the proposed cooperative approaches.