Table 1.

Summary of surveys relevant to ML-enabled O-RAN. H: High, M: Medium, and L: Low.

Year	Ref	O-RAN Architecture	ML Application in O-RAN	Research Opportunities	Remarks
2023	[1]	H	M	M	This paper provides a detailed tutorial on O-RAN, describing its architecture, design principles, and the O-RAN interfaces.
2021	[4]	H	L	L	This paper overviews the idea of O-RAN and presents ongoing O-RAN Alliance standardization activities in this context, followed by a study of traffic steering use case.
2022	[12]	H	L	L	This paper provides a comprehensive survey of O-RAN development, encompassing a summary of the RAN evolution history, an introduction to O-RAN technology, an overview of Open RAN-related projects and activities, a discussion of standardization efforts, challenges, and potential solutions.
2021	[13]	M	L	L	This paper provides an overview of the O-RAN Alliance RAN architecture, highlighting its core building blocks and, subsequently, it presents a practical use case that leverages AI/ML-based innovations.
2022	[14]	H	M	M	This paper presents an O-RAN architecture overview, delves into AI applications within Op-RAN, and discusses the challenges and opportunities in implementing intelligent solutions in 5G and B5G telecommunications.
2022	[15]	H	M	M	This paper focuses on mapping existing deep-learning-based studies to the O-RAN architecture, highlighting key technical challenges, open issues, and future AI-enabled O-RAN research directions.
2023	[16]	M	L	L	This paper examines security and privacy risks in O-RAN architecture, proposes possible solutions and presents relevant security standardization efforts.
2023	[17]	M	L	L	This paper focuses on Non-Terrestrial Networks exploring the possible implementation of an O-RAN-based NTN solution.
2022	[18]	H	L	L	This paper identifies critical limitations in current O-RAN specifications: security, latency, real-time control, and AI-based RAN control.
2023	[19]	H	M	L	This paper focuses on XAI methods and explores their deployment within the context of O-RAN.