Optimal energy-efficient transmission for hybrid spectrum sharing in cooperative cognitive radio networks

In order to improve the energy efficiency (EE) in cognitive radio (CR), this paper investigates the joint design of cooperative spectrum sensing time and the power control optimization problem for the secondary user systems to achieve the maximum energy efficiency in a cognitive network based on hybrid spectrum sharing, meanwhile considering the maximum transmit power, user quality of service (QoS) requirements, interference limitations, and primary user protection. The optimization of energy efficient sensing time and power allocation is formulated as a non-convex optimization problem. The Dinkelbach's method is adopted to solve this problem and to transform the non-convex optimization problem in fractional form into an equivalent optimization problem in the form of subtraction. Then, an iterative power allocation algorithm is proposed to solve the optimization problem. The simulation results show the effectiveness of the proposed algorithms for energy-efficient resource allocation in the cognitive network.