What is C-RAN?
C-RAN is a RAN architecture that moves baseband processing functions away from individual cell sites into centralised Baseband Unit (BBU) pools, while Remote Radio Heads (RRHs) remain at the antenna site. This separation enables resource pooling, coordinated multi-cell processing, and easier evolution toward cloud-native RAN.
How Does C-RAN Work?
The BBU pool handles channel coding, MIMO processing, and scheduling for multiple cells. RRHs at cell sites convert between digital baseband (received via fronthaul) and analogue RF. The fronthaul link — traditionally CPRI over fibre — carries digitised IQ samples between BBU and RRH. Open RAN evolves C-RAN further by defining open interfaces between RU, DU, and CU.
Use Cases
Dense urban deployments where centralised BBU pools reduce site costs, enabling CoMP (Coordinated Multipoint) across cells, foundation for cloud RAN (vRAN) and Open RAN evolution.
3GPP / Standards Reference
3GPP TR 38.801 (Study on New Radio Access Technology), O-RAN Alliance specifications
Related Terms
RRH | Fronthaul | Open RAN | CoMP | CPRI | Midhaul
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This glossary entry is part of the 5GWorldPro Complete 5G Glossary. To go deeper into 5G architecture and technology, explore our 5G Training courses.
