Abstract
The dynamic nature of modern network settings presents challenges for traditional base stations, leading to inefficient resource utilisation. These issues are exacerbated by the unpredictability of network scenarios, such as unexpected hardware problems or sudden increases in user demand. More adaptive and intelligent systems that can handle these issues are becoming increasingly critical and essential. Open-RAN is an intelligent and adaptable mobile network architecture featuring learning-based capabilities and a software layer for adaptation that can incorporate AI and ML to optimise communication networks and improve resource efficiency. Hence, this article aims to systematically review intelligence for Open-RAN through the adoption of the RAN Intelligent Controller (RIC). This comprehensive review also includes (1) real-world use cases for various industries, (2) the potential use cases for various intelligent models in terms of 5G core, RAN and air interface, (3) the advantages and challenges of AI incorporation within Open-RAN, and (4) the societal, environmental and economic impact of Open-RAN intelligence. This article outlines the significance of intelligence in the context of Open-RAN and highlights potential use cases, examining their impact and presenting challenges for further exploration by researchers in the field.