Intelligent O-RAN for Beyond 5G and 6G Wireless Networks

Building on the principles of openness and intelligence, there has been a concerted global effort from the operators towards enhancing the radio access network (RAN) architecture. The objective is to build an operator-defined RAN architecture (and associated interfaces) on open hardware that provides intelligent radio control for beyond fifth generation (5G) as well as future sixth generation (6G) wireless networks. Specifically, the open-radio access network (O-RAN) alliance has been formed by merging xRAN forum and C-RAN alliance to formally define the requirements that would help achieve this objective. Owing to the importance of O-RAN in the current wireless landscape, this article provides an introduction to the concepts, principles, and requirements of the Open RAN as specified by the O-RAN alliance. In order to illustrate the role of intelligence in O-RAN, we propose an intelligent radio resource management scheme to handle traffic congestion and demonstrate its efficacy on a real-world dataset obtained from a large operator. A high-level architecture of this deployment scenario that is compliant with the O-RAN requirements is also discussed. The article concludes with key technical challenges and open problems for future research and development.

I. Introduction

The existing 5G wireless architecture lacks sufficient flexibility and intelligence to efficiently handle stringent and diverse demands [1]. As a result, the evolution towards beyond 5G and sixth generation (6G) wireless calls for an architectural transformation required to support service heterogeneity, coordination of multi-connectivity technologies, and on-demand service deployment. Open radio access network (RAN) is an emerging idea that enables such a transformation using the concepts of virtualization, flexibility, and intelligence. Naturally, over the last few years, multiple independent alliances and forums have initiated research on accelerating this transformation of RAN by increasing infrastructure virtualization, combined with embedded intelligence to deliver more agile services and advanced capabilities to end users.