Radio Access Network (RAN) virtualization is a promising commercial solution where multiple service providers can share underlying radio physical resources and dynamically compose heterogeneous virtual networks that coexist in isolation within the same physical infrastructure. Based on the expected future requirements, this work proposes a solution named Resources nEgotiation for NEtwork Virtualization (RENEV), which can be applied in Long Term Evolution-Advanced (LTE-A) environments, consisting of numerous small cells. This algorithm aims at achieving an efficient mapping of radio virtual network elements onto the radio resources of the existing physical network, utilizing the concept of radio resource transfer. It establishes a common virtualized control layer by handling the resources in an holistic way. The proposed solution achieves significant gains in terms of system throughput and its performance is evaluated by means of analytical model, as well as simulation results.