In brief, C-RAN or Centralized RAN is to moving the BBU to a central office. This logical step is possible due to the fact that optical fibers are available between the antenna site and central office. Here when we’re talking about BBU or Baseband Processing Unit we mean the brain of the cell site.
The brains at the base of the cell site are moved back to a centralized location and One centralized unit can handle hundreds of small cells being built across a city.
The main benefits of this are:
- C-RAN centralized coordination of radio resources to optimize the user experience and spectral efficiency. Rather than a base station connected to a radio at the top of a tower, multiple radio points are connected via fronthaul to a baseband.
- The ability to upgrade very quickly; that software happens in one place across hundreds of small cells.
- Add additional future functionality as having fiber and building fiber is a very important part of how you do small cells.
Here, I am talking about Centralized RAN not Cloud RAN as Cloud RAN Where some network functions start being virtualized in the cloud.
C-RAN enables operators to house base station equipment at one centralized location that may be as far as 15 miles away from
the radio units.
Several baseband units can share one location, which can be an existing carrier data center, the base of a cell tower, or another secure location that is potentially less expensive than the remote sites where the radios and antennas are.