Road to Dynamic Functional Split in Radio Access Networks

The ever-growing bandwidth requirements of mobile networks have prompted the re-evaluation of a centralized architecture for Radio Access Networks (RANs). Although relieved by optical connections, the bottleneck inherent with C-RANs can impede future service delivery. Changing to a non-static functional architecture may be better suited for evolving scenarios. Different options have been outlined to split the Base Band Units (BBUs) protocol stack functionality to meet the envisioned demands while minimizing Capital Expenditure (CAPEX). The bandwidth requirement between split functions varies greatly depending on the Functional Split (FS) chosen. The emergence of Network Function Virtualization (NFV), and the possibility of using Commercial off-the-shelf (COTS) components with specialized software allows for easy repair and maintainability. By deploying BBU functions virtually on COTS nodes, enabling the architecture adjustment on a use-case basis, Operating Expenditure (OPEX) can be further reduced. This work covers the solution of Dynamic Functional Split (DFS), the deployment requirements, and how they affect the envisioned RAN architecture. The conclusion reached is that addressing the needs of the emergent mobile networks with a DFS unlocks new opportunities for using RAN resources.