First, We need to understand the most important question, Why do we need to change our RAN from a traditional setup to a more flexible one?
The Answer is: Heavy Data Growth
Each new mobile technology generation has delivered greater data rates to mobile devices, and mobile users have moved more and more of their data usage from fixed devices to their smartphones, tablets, and other devices. In addition to social media, video streaming is now commonplace on small screens.
So Operators must simultaneously increase bandwidth to cell towers and mobile users while reducing the cost of transport.
What is the Distributed RAN?
The present mode of operation is the distributed RAN architecture, in which the RRH and the BBU RAN functions are all located at the cell sites and are all backhauled into a central switching center. This architecture was effective at 3G, but may not deliver the required combination of greater bandwidth at lower costs for advanced versions of 4G. At 5G, where data rates to devices will hit 1 Gbit/s, many mobile operators have concluded that the distributed RAN architecture will not be viable.
Moving from Distribute RAN to C-RAN
The “C” denotes both “centralized” and “cloud” – two separate but related aspects of this new architecture. The new centralized RAN architecture places only the RRH at the cell tower and moves the BBU functions to the centralized BBU hotel (or BBU pool).
The Benefits of Centralized the BBUs
Centralizing the BBUs provides several benefits to MNOs
- High Efficiency and Utilization: In the traditional RAN architecture, each cell site requires its own dedicated BBU, along with the associated power, cooling, and routing.
Centralizing the BBUs in one location allows the BBU pool to share the same data center/central office physical space, batteries, electricity generators, and cooling sources.
Also, the BBU pool can be served by one large router, rather than separate, smaller routers required at each cell site. In short, the physical pooling ensures that all data center infrastructure and routing resources are used most efficiently and with the least amount of idle capacity and waste.
- Reduced OPEX from sending technicians to cell towers for maintenance: Further operational savings from centralizing BBUs come from equipment and site With a centralized RAN, technicians don’t need to be dispatched out to cell towers for troubleshooting and routine maintenance of the BBUs.
- Improved performance due to greater coordination among cells: Economies of scale and reduced maintenance are the most significant benefits of physical centralization, but centralization provides performance improvements, even without any virtualization.
The Difference between D-RAN and C-RAN
A C-RAN architecture consists of three main components: the baseband unit pool (BBU), the remote radio head (RRH), and the transport network connecting the RRH and the BBU called the fronthaul network.
In a distributed RAN, the RRH and BBUs are typically separated within the cell tower, with the RRH atop the tower and the BBU at the bottom. The Common Public Radio Interface (CPRI) protocol was standardized specifically for this connection.
As we saw from the above figure (Source: Fujitsu & Heavy Reading) that in D-RAN the capacity at each site is under-utilized much of the time, However in C-RAN, Utilization increases, and fewer elements are needed to scale RAN Capacity which means saving Capex.
We are in 2022, Have 4 mobile generations 2G,3G,4G, and 5G. All of them are coming with new data growth, new customer experience, and more RAN Challenges. If MNOs didn’t change their RAN_Mindset, they will be shocked in the next upcoming years by the fact that their Opex and Capex are not proportional to the revenues.
If they continue in Traditional_RAN, they will need to invest in more Proprietary HWs, Software Upgrades, Sites Heavy Maintenance, and also more effort and time with manual site-by-site configuration.
Let’s Chane Our RAN Mindset and Open the RAN 🙂
Next Article, I will explain Why we need to go for vRAN and Open RAN … Stay Tuned!