The evolution of wireless networks has led to the deployment of different Radio Access Technologies (RATs) such as GSM/EDGE Radio Access Network (GERAN), UMTS Terrestrial Radio Access Network (UTRAN) and Long Term Evolution (LTE). Next Generation Wireless Networks (NGWNs) are predicted to interconnect various Third Generation Partnership Project (3GPP) Access Networks with Wireless Local Area Network (WLAN) and Mobile Worldwide Interoperability for Microwave Access (WiMAX). A major challenge is how to allocate users to the most suitable RAT for them. An intelligent solution will lead to efficient radio resource utilization, maximization of network operator’s revenue and increasing in the users’ satisfactions. Common Radio Resource Management (CRRM) was proposed to manage radio resource utilization in heterogeneous wireless networks. This paper discusses the need of CRRM for NGWN. Then, the paper presents a comparison between implementing or not the CRRM in heterogeneous wireless networks. After that, the interaction between RRM and CRRM entities is discussed. Then, different approaches for the distribution of RRM and CRRM entities among the Core Network (CN), RATs and User Terminals (UTs) will be presented. Finally, a comparison between distributed and centralized algorithms is presented.