ABSTRACT
This chapter presents an overview of the evolution of radio access network (RAN) technologies and the latest trends toward virtualized, open and intelligent next generation RAN. It also presents the evolution of the RAN architectures and their specific characteristics. The chapter provides an overview of the development of different RAN architectures throughout the evolution of the mobile networks towards the cloud-RAN (C-RAN) architecture. Different types of C-RAN, namely heterogeneous Cloud-RAN, virtualized Cloud-RAN, and Fog-RAN, are considered based on surveys and other related publications. C- RAN allows the energy consumption to be decreased, the resource management to be improved, and the network management, maintenance and scalability to be optimized. Software-Defined Networking offers a logically centralized and flexible control model and the possibility of resource sharing that could be implemented in RAN. A centralized C-RAN solution and open platforms based on software defined radio can upgrade the RAN architecture.
