Deployment of next-generation networks (i.e. 4G) begins to spread throughout the world. Today's emerging multimedia application has many requirements in terms of quality of service and users always want to be best connected anywhere, anytime, and anyhow. To satisfy these demands, a variety of access technologies has become available: WiFi (Wireless Fidelity), WiMAX (Worldwide Interoperability for Microwave Access), and Cellular networks. This has made it difficult for service provider to select the best network for requesting services and to control the quality level of ongoing connections. Thus, the use of resources management to prevent overloaded or underutilized networks as well as to best satisfy users is indispensable. This paper addresses the state of the art on radio resource management in next-generation networks. Recent schemes in network selection and bandwidth allocation are discussed in several aspects, namely decision making, QoS, mobility, and architectural design.