Energy-Constrained Cooperative Spectrum Sensing in Cognitive Radio Networks

How to set spectrum sensing duration is an important issue in Cognitive Radio (CR) networks, which could greatly affect energy efficiency and system throughput. Over sensing would result in insufficient transmission period, while inadequate sensing would incur false alarm and miss detection. This paper studies how to choose an optimal sensing duration to strike a balance between energy consumption and system throughput. We focus on a cooperative sensing scenario, where several secondary users form a group to guarantee more accurate sensing results. By formulating the transmission cost in terms of the energy consumption of sensing process and transmission process, we propose a comprehensive utility function. The maximization of the utility function is obtained with the constraints of sufficient protect for primary users. The existence of the optimal sensing duration is proved accordingly. Numerical results show that secondary users can achieve almost the maximum throughput with significant energy saving when utilizing optimal sensing duration.