convergence of traditional cellular networks and cloud computing platform. From RAN perspective, the role that cloud computing plays in networks calls for a holistic vision that allows control, optimization and management of both network and computing resources in a cloud-based environment. Virtualization can be viewed as a profound enabler for the convergence of networks and cloud. As shown in Fig. \[fig:cloudconvergence\], radio resource and computing resources can be effectively, flexibly and efficiently virtualized into services. Then, both resulted XaaS in communication and computing domains should be properly combined for service provisioning to the end-users.

Indeed, the previous research on the RAN optimization usually focus on the radio resource allocation, such as spectrum or power, based on the channel state information, without considering the computing resource and other contextual information, while most of the research of cloud computing concentrate on the computing resources allocation [@Duan1]. The limitation of previous work will motivate the research on a joint consideration of radio and computing resources. The challenges, in this respect, may come from the design of a metric to measure the radio and computing platform and to propose corresponding optimization methods. Moreover, the protocols design between the computing resource providers and radio resource 