Abstract: An innovative EE-oriented 'win-win' cooperative transmission scheme in heterogeneous cognitive radio networks (Het-CRNs), called energy-efficient cognitive cooperation (ECC), in which primary system release a part of its radio spectrum to secondary system in exchange for secondary relay (SR) served as a relay to assist transmission of primary user's traffic under the dual quality of service (QoS) requirements. Then, secondary user's traffic flow is split into the unlicensed spectrum and the released licensed spectrum to improve EE in Het-CRNs. Based on ECC, we formulate a weighted EE maximization non-convex problem for secondary users. By employing parametric fractional programming and golden section search (GSS) method, an efficient resource allocation policy is developed. Simulation results show that the proposed strategy can gain significantly higher EE without reducing performance of primary transmission, and thus, a 'win-win' goal is achieved.