Energy efficient resource allocation for cognitive radio networks with imperfect spectrum sensing

This paper investigates the energy efficient resource allocation strategy for OFDM-based cognitive radio (CR) networks with imperfect spectrum sensing. The interference model taking the sensing errors into account is formulated at first. And the objective is to maximize the energy efficiency of the multiuser CR system subject to the total transmission power budget and each primary user´s (PU) interference constraints. As the primal problem is a mixed integer nonlinear programming issue, we will separate the resource allocation scheme into two steps, i.e., subcarrier assignment and power allocation. After the suboptimal subcarrier assignment, an optimal power allocation algorithm is proposed based on fractional programming and sub-gradient method. The simulation results show that the proposed resource allocation scheme can achieve higher energy efficiency than the one maximizing the capacity of the CR networks. Meanwhile, it can protect the normal communication of each PU compared to the scheme without considering sensing errors.