This report investigates Radio Access Network (RAN) - Core Network (CN) convergence as a key direction for 6G networks, addressing limitations in current 3GPP and O-RAN architectures. By decentralizing CN functions (e.g., user plane, control plane, or both) to the edge and functionally integrating RAN-CN components, RAN-CN convergence aims to enhance performance, security, and resource efficiency while reducing latency and overhead. Key use cases include enterprise private networks, edge intelligence, and massive IoT access. This report identifies convergence functionalities (session/state/mobility management) and proposes a converged reference architecture based on end-to-end service-based architecture. Impacts on existing frameworks (e.g., protocol stacks, signaling procedures) are analyzed, alongside challenges like security, privacy, and standardization. RAN-CN convergence emerges as a pivotal 6G strategy, with this report offering foundational insights for future architecture design.
