Optimal Energy-Efficient for OFDM-Based Cognitive Relay Networks with Sensing Errors

In this paper, the energy efficiency maximization problem in OFDM-based cognitive relay networks with incomplete spectrum sensing is investigated. Firstly, a secondary relay transmission system model is established where the interference limitation, the incompleteness of spectrum sensing, and the maximum transmit power are considered. The joint optimization energy efficient model of spectrum sensing and transmission problem is mixed-integer nonlinear programming problem in the NP problem, it is difficult to find the optimal solution directly. Therefore, the fractional programming is used to solve the problem to reduce the complexity of the algorithm by convex optimization. Simulation results show the effectiveness of the proposed algorithms.