FROM LEGACY RAN TO OPEN RAN:
AN EVOLUTIONARY PERSPECTIVE
Traditional RAN architectures were based on
the Distributed Radio Access Network (D-RAN)
model. Here, Baseband Units (BBUs) and
Remote Radio Heads (RRHs) were proprietary
and usually co-located at the same cell site.
The move towards a Centralized RAN (C-RAN)
saw the creation of a "centralized BBU pool."
However, the Common Public Radio Interface
(CPRI)-based fronthaul struggled to meet the
capacity and performance requirements of 5G
networks.
Both D-RAN and C-RAN architectures come
with high operating expenses (Opex),
underutilization of RAN resources, and limited
deployment flexibility for 5G.
Cloud RAN, or C-RAN, emerged as a solution to
these challenges. It built upon the
centralization concept by running virtualized
baseband functions on Commercial Off-The-
Shelf (COTS) server hardware. This model
leveraged Network Functions Virtualization
(NFV) to create a more flexible and scalable
architecture.
The Cloud RAN paradigm gradually evolved
into Open RAN, expanding on openness
and embedded intelligence principles. The
openness in the architecture facilitated
multi-vendor deployments, reducing
vendor lock-in and promoting competition.
The embedded intelligence leveraged
advanced technologies like Machine
Learning (ML) and Artificial Intelligence
(AI) to automate operational network
functions, further reducing operational
costs.
Overall, Open RAN represents a substantial
progression in RAN architectures, offering
benefits in terms of cost, flexibility, and
performance. Open RAN is poised to play a
pivotal role in 5G deployments and beyond
by embracing open standards and
intelligent functionalities.
5G MAGAZINE | #06
