Energy-Efficient Spectrum Discovery for Cognitive Radio Green Networks

Cognitive Radio (CR) is an essential technique for the future generation green communication paradigm owing to its inherent advantages of adaptability and cognition. The compulsory spectrum sensing is a critical component to facilitate systems co-existence. In this paper, we propose a new Time-Division Energy Efficient (TDEE) sensing scheme in which the sensing period is divided into an optimal number of timeslots and each Secondary User (SU) is assigned to detect a different channel in one time-slot. An important advantage of TDEE is that the SUs do not need to exchange the control messages for the acknowledgement of a successful cooperation, leading to substantial energy saving without compromising sensing accuracy. Both homogeneous and heterogeneous networks are investigated with respect to the intrinsic trade-off between spectrum efficiency and energy-efficiency. Illustrative results demonstrate that the proposed TDEE is able to achieve much lower energy consumption and higher throughput, compared to the existing mechanisms.