Toward reconfigurable RAN in beyond 5G: A survey of architectural design, planning, and operation

The evolution toward Beyond 5G (B5G) and 6G networks is driving a fundamental transformation of the Radio Access Network (RAN), requiring systems that are flexible, scalable, and capable of adapting to highly dynamic service demands. Reconfigurable RAN has emerged as a key paradigm to address these challenges, enabling dynamic control over network structure, resource allocation, and service delivery. This paper presents a survey of reconfigurable RAN, bridging architectural design, network planning, and operational management within a single review. From a design perspective, we examine key enablers including functional splits, Open RAN (O-RAN), the integration of Artificial Intelligence (AI) and energy efficiency. From a planning perspective, we analyse network dimensioning, virtualised RAN functions, and placement strategies that determine system scalability and cost-efficiency. From an operational perspective, we review resource allocation and network slicing as mechanisms for real-time adaptation to heterogeneous traffic and service requirements. In addition, we explore cross-cutting themes including energy efficiency and AI-native orchestration, highlighting their role in enabling sustainable and intelligent network operation across converged and heterogeneous environments. By connecting these traditionally separate domains, this survey provides a holistic view of reconfigurable RAN and identifies key challenges and opportunities for future B5G and 6G systems. The insights presented aim to support the development of next-generation networks that are not only high-performing, but also adaptive, efficient, and sustainable.