Plans for virtual RANs
Telecom operators are looking to extend the benefits of virtualization to radio access networks (RANs). Companies such as Nokia, Intel and Verizon are working to leverage RAN architectures like virtual RAN in preparation for the 5G and IoT era. But what exactly is a virtual RAN, and how does it differ from a traditional RAN architecture?
The role of virtualization in the RAN
Virtualization involves decoupling software from hardware, enabling network operators to develop and deploy innovative services automatically. With technologies like network functions virtualization (NFV), for example, operators can quickly deliver customizable services with virtual machines that run on inexpensive nodes. This makes the network more agile, while reducing the need for expensive proprietary hardware.
Similarly, a virtual RAN applies the principles of NFV by virtualizing network functions, providing a greater degree of flexibility in the RAN in return. A virtual RAN consists of a centralized pool of baseband units (BBUs), virtualized RAN control functions and service delivery optimization. With a virtual RAN, baseband modules are moved away from the base station and to a data center. As a result, functions of the BBUs can be implemented with virtual machines in a centralized data center. This provides intelligent scaling of computing resources, while decreasing energy consumption and capital expenditure (CAPEX).
Virtual RAN for 5G
The virtualization of the RAN is expected to help carriers prepare for 5G networks, which further increase bandwidth requirements. For example, a 5G virtual base station can improve system capacity and spectral efficiency by drawing from a pool of BBUs that share signaling among cells. A virtual RAN can also help simplify the deployment of novel features and algorithms, which optimize resource usage and enhance the end-user experience.
Moreover, the centralized architecture of a 5G virtual base station enables control plane and data plane splitting to be easily implemented. Additionally, by decoupling network functions from proprietary hardware, a virtual RAN can enable a level of adaptability in networks that operators need for the commercialization of 5G. A virtual RAN allows mobile operators to future-proof networks for 5G upgrades as well.
Challenges
A virtual RAN is harder to implement compared to other NFV implementations like virtual evolved packet core. This is in part due to the fact that the centralization of RAN functions demand high-bandwidth and low-latency between the base station and data center. Furthermore, moving the baseband processor from the bottom of a tower into a data center can require a lot of fiber that is expensive to install. Some companies are working on developing architectures that require less fiber to virtualize the RAN. The pool of BBUs sharing resources in a virtualized RAN architecture pose the risk of breaking user privacy and accessing sensitive data too.
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