In previous chapter we shall learned about RRU, BBU, CU, DU fronthaul, midhaul; In this chapter we shall learn about:
D-RAN vs C-RAN vs vRAN vs O-RAN
What is D-RAN?
DRAN stands for “Distributed RAN”.
In this type, RRU and BBU are co-located at every cell site.
This has several issues in terms of space and capacity needed at the base stations.
These type of RAN were not designed to meet short bursts of traffic (example any event nearby).
They are run using proprietary software on specialized hardware.
Each cell site are connected back to the core network through backhaul.
What is C-RAN or Cloud RAN?
C RAN stands for Centralized RAN or Cloud RAN.
They are often used interchangeably.
Here the BBU is moved to a Centralized location and the cell site has only antenna and the RRU.
RRU is connected to the BBU Pool using fronthaul.
There is no concept of 1:1 connection between RRU and BBU.
Because of this change, maintenance cost per site will be reduced.
In addition to that BBU can be split into DU and CU.
DU will be connected to CU using midhaul.
Here the software and hardware needs to be taken from single vendor.
What is vRAN OR Virtual RAN ?
vRAN uses virtualization technologies such as NFV or containers to deploy CU and DU.
The main difference between vRAN and C-RAN is that C-RAN uses proprietary hardware while vRAN uses virtualization platform.
With vRAN, it will allow operator to run the BBU software to run on Commercial Off The Shelf (COTS) server hardware.
And they can run RRU with Virtualized BaseBand Units (vBBU).
What is O-RAN or Open RAN?
O-RAN and Open RAN are from O_RAN alliance.
Traditionally vRAN or D-RAN are part of RAN that are from same vendor. Customers have to take the hardware and software from the same vendor.
O-RAN is working on a specification to open the interface between RRU, DU and CU. So that customers can buy the software and hardware from different vendors.
So according to O-RAN, the specs are called as O-RU, O-DU and O-CU.