Bharat Agarwal; Ralf Irmer; David Lister; Gabriel-Miro Muntean

Enhancing the radio access network (RAN) architecture has been the focus of some of the latest global operators’ concentrated effort, building on principles of intelligence and openness. The goal is to develop an operator-defined RAN architecture (as well as related interfaces) on an open hardware that will enable intelligent radio control for the Fifth Generation (5G) networks beyond, especially the Sixth Generation (6G) wireless networks. The transition to 6G is anticipated to be made simpler by this Open RAN architecture. The reduced cell radius of the 6G mobile networks, which will use significantly higher frequencies, will severely limit their ability to penetrate buildings. Radios will need to be positioned closer to subscriber devices and indoor installations will need to be used in order to accommodate these changes. Operators will require a greater variety of form factors and potentially even new types of front-haul in order to deploy affordably large numbers of Radio Units (RU) indoors. By having open interfaces between the Distributed Unit (DU) and RU, Mobile Network Operators (MNOs) will have access to a much wider range of RUs with various form factors and customizable features. This survey summarizes the different possible architectures for 6G Open RAN, especially considered from the perspective of energy efficiency, and low latency. Next, it presents various novel use cases which can employ 6G Open RAN architectures. Lastly, the prospects and problems facing Open RAN in 6G are discussed. Design principles and potential fixes for sophisticated processes are also provided.