Virtualizing RAN: Science, Strategy, and Architecture of Software-Defined Mobile Networks

Virtualizing the Radio-Access Network (RAN) is increasingly viewed as an enabler of affordable 5G expansion and a stepping-stone toward AI-native 6G. Most discussions, however, still approach spectrum policy, cloud engineering and organizational practice as separate topics. This paper offers an integrated perspective spanning four pillars -- science, technology, business strategy and culture. A comparative U.S.\ case study illustrates how mid-band contiguity, complemented by selective mmWave capacity layers, can improve both coverage and churn when orchestrated through software-defined carrier aggregation. We derive analytic capacity and latency bounds for Split 7.2 $\times$ vRAN/O-RAN deployments, quantify the throughput penalty of end-to-end 256-bit encryption, and show how GPU/FPGA off-load plus digital-twin--driven automation keeps the hybrid-automatic-repeat request (HARQ) round-trip within a 0.5 ms budget. When these technical enablers are embedded in a physics-first delivery roadmap, average vRAN cycle time drops an order of magnitude -- even in the presence of cultural head-winds such as dual-ladder'' erosion. Three cybernetic templates -- the Clock-Hierarchy Law, Ashby's Requisite Variety and a delay-cost curve -- are then used to explain why silo-constrained automation can amplify, rather than absorb, integration debt. Looking forward, silicon-paced 6G evolution (9-12 month node shrinks, sub-THz joint communication-and-sensing, chiplet architectures and optical I/O) calls for a dual-resolution planning grid that couples five-year spectrum physics with six-month silicon sprints.'' The paper closes with balanced, action-oriented recommendations for operators, vendors and researchers on sub-THz fronthaul, AI-native security, energy-proportional accelerators and zero-touch assurance.