Open RAN - What does an open architecture of the radio access network enable

Radio Access Network (RAN) is becoming increasingly complex due to technological innovations, such as massive MIMO, network slicing, dual connectivity, dynamic spectrum allocation, etc. The complexity of the network is growing also due to the diversity of its implementation, various cell sizes, spatial provisioning, fixed wireless access, and different connection methods. This leads to high investment and operational costs for operators who are coping with the challenges of aligning with the market trends and technological development. Mobile networks are therefore shifting from closed architectures to open radio access networks (Open RAN or O-RAN). The paper analyses the differences between the traditional distributed radio access network (D-RAN) and the centralized radio access network (C-RAN). The modern concept disaggregates the base station, intelligent RAN controller, virtualization and open interfaces. The disaggregation allows separate processing of radio resources and protocol, optimizing the network. The intelligent RAN controller enables programmability, coordination with other networks, and the execution of optimization routines. Virtualization brings the possibility of better resource utilization, while open interfaces enable better connectivity and interoperability between different parts of the network. The paper emphasizes the advantages and disadvantages of ORAN. Advantages include interoperability, open interfaces, virtualization, functional disaggregation, and faster innovation. Disadvantages include complexity, security challenges, and the need for standardization. Despite these challenges, O-RAN promises greater flexibility, better resource utilization, and faster introduction of innovations into mobile networks. © 2023 Electrotechnical Society of Slovenia. All rights reserved.