In communication networks, a cognitive network (CN) is a new type of data network which is used to solve some of the problems that face current networks. Cognitive radio (CR) is part of a cognitive network and a smart wireless communication system. CR is conscious of its surrounding environment, and learns from the environment. It adapts its internal states by making corresponding real-time changes in certain operating parameters. In this paper, we propose a novel Cognitive RBAC (Role-Based Access Control) scheme which can be applied to Mobile Heterogeneous Networks (MHNs). The MHNs consist of mobile communication systems and Wi-Fi systems. The required new definitions for the RBAC model are proposed in this paper. They can improve the ability of conventional RBAC model to meet new challenges. In our scheme, we assume that a Cognitive Server (CS) provides and manages the permissions of services, and Network Providers support and manage a variety CRs and CNs, individually. For more efficiently managing CR and CN and meeting the large scale heterogeneous networks, we let mobile user can perceive network candidate actively to access services, in which the permissions are depending to the contract made by CS with each Network Provider. In this paper, the new generalized cognitive RBAC model and their definitions are proposed, and could be applied to new applications in a MHNs environment.