The ability to intelligently utilize resources to meet the need of growing diversity in services and user behavior marks the future of wireless communication systems.Intelligent wireless communications aims at enabling the system to perceive and assess the available resources,to autonomously le to adapt to the perceived wireless environment,and to reconfigure its operating mode to maximize the utility of the available resources.The perception capability and reconfigurability are the essential features of cognitive radio while mod machine leing techniques project great potential in system adaptation.In this paper,we discuss the development of the cognitive radio technology and machine leing techniques and emphasize their roles in improving spectrum and energy utility of wireless communication systems.We describe the state-of-the-art of relevant techniques,covering spectrum sensing and access approaches and powerful machine leing algorithms that enable spectrum and energy-efficient communications in dynamic wireless environments.We also present practical applications of these techniques and identify further research challenges in cognitive radio and machine leing as applied to the existing and future wireless communication systems.