Energy-Efficient Cooperative Strategy in RF Energy Harvesting Cognitive Radio Network

Energy-efficient cooperative spectrum sharing has become a new trend based on financial and environmental considerations. We focus on a novel energy-efficient cooperative strategy in a Radio frequency (RF) energy harvesting cognitive radio network, where the Secondary user (SU) provides energy supply and relaying assist for the Primary user (PU) in exchange for the transmission opportunities. On the basis of energy and information cooperation, an Energy efficiency (EE) maximization non-convex problem for SU is formulated under the PU's Quality of service (QoS) requirement and energy-causality constraint. With the aid of Dinkebalch's method and convex optimization technique, a joint time and power allocation scheme is proposed. Numerical results show that the proposed scheme achieves higher SU's EE and better PU's QoS guarantee compared to the scheme in which the SU only provides energy for the PU's transmission.