Radio access network is an academic concept and research domain encompassing the technologies, protocols, and architectures that facilitate wireless communication between user equipment and the core network infrastructure. This field investigates critical aspects such as spectral efficiency, interference management, resource allocation, mobility, and physical layer design, focusing on the wireless 'last mile'. Characterized by the study of base station functionalities, air interfaces, heterogeneous network deployments, and the application of virtualization and AI/ML for optimization, its significance lies in enabling mobile broadband, supporting diverse applications, and addressing performance challenges in modern and future wireless communication systems.