In this paper, we tend to investigate the energy-efficient resource allocation in orthogonal frequency division multiplexing (OFDM)-based cognitive radio (CR) networks, where we tend to try and maximize the system energy-efficiency under the thought of many practical limitations, such as transmission power budget of the Cr system, interference threshold of most important users and transmit demands of secondary users. Our general objective formulation leads to a challenging mixed integer programming problem that's hard to solve. To form it computationally tractable, we employ a time-sharing methodology to change it as a non-linear partial program problem, which may be further converted into an equivalent convex optimization problem by using its hypogragh kind. Supported these transformations, it is possible to obtain (near) best possible explanation by usual optimization method. However, the complexness of the standard technique is just excessively high for this real-time optimization project. By utilize the structure of the problem extensively; we develop an efficient barrier methodology to work out the (near) best solution with an affordable complexness, significantly higher than the standard technique. Numerical results show that our proposal can maximize the energy efficiency of the Cr system, whilst the proposed algorithmic rule performs quickly and stably.