The evolution of wireless communication systems from 1G to 5G has consistently expanded technical frontiers and societal expectations of connectivity. However, the increasing demands of emerging applications—including holographic communications, immersive extended reality (XR), and large-scale digital twins—necessitate a paradigm shift beyond the architectural limitations of 5G. Sixth-generation (6G) networks are envisioned as intelligent, adaptive, and context-aware infrastructures, with Artificial Intelligence (AI) serving as a native enabler across all network layers. This paper investigates the emerging concept of the AI-native Radio Access Network (AI-RAN), which reconceptualizes the RAN as a compute-converged platform where communication and intelligence are intrinsically integrated. We present the architectural vision of AI-RAN through three complementary paradigms—AI-for-RAN, AI-on-RAN, and AI-and-RAN—and articulate four foundational attributes: AI-native communication, sustainability, ubiquitous coverage, and security and resilience. By consolidating these perspectives, this work provides a conceptual foundation for building scalable, trustworthy, and sustainable AI-RAN systems in the 6G era. This research work focuses on sustainability, ubiquitous coverage, and intelligent infrastructure, which is fundamentally aligned with SDG 9 (Industry, Innovation, and Infrastructure) by pioneering the resilient and innovative infrastructure required for a connected future.
 

6G, AI-RAN, artificial intelligence, radio access network, ubiquitous coverage, sustainability, security, AI-native communication, next-generation networks.