Towards energy-efficient cooperative spectrum sensing for cognitive radio networks: an overview

Cognitive radio has been proposed as a promising technology to resolve the spectrum scarcity problem by dynamically exploiting underutilized spectrum bands. Cognitive radio technology allows unlicensed users to exploit the spectrum vacancies at any time with no or limited extra interference at the licensed users. Usually, cognitive radios create networks in order to better identify spectrum vacancies, avoid resultant interference, and consequently, magnify their revenues. One of the main challenges in cognitive radio networks (CRNs) is the high energy consumption, which may limit their implementation especially in battery-powered terminals. The large consumption mainly occurs during the spectrum sensing stage, especially if a cooperative approach is employed, and has an impact on the data transmission stage. Many algorithms have been proposed in the literature in order to improve the energy efficiency of cooperative spectrum sensing methods in CRNs. In this article, we provide an overview of state-of-the-art research that addresses this problem. Furthermore, we suggest important design guidelines of an energy-efficient framework for cooperative spectrum sensing.