What is REC?
REC (Radio Equipment Controller) is the virtual or physical component of a base station that performs digital baseband control of the radio system. In the CPRI (Common Public Radio Interface) standard, the REC is the centralised processing unit that handles higher-layer functions — channel coding, modulation, interleaving, scheduling, and power control — and sends digitised IQ samples to the RE (Radio Equipment) at the antenna site via the CPRI fronthaul link. The REC concept maps to the BBU in traditional architectures and to the DU/CU in 5G disaggregated architectures.
How Does REC Work?
The REC handles all digital processing above the PHY layer and the upper PHY processing itself. It receives user data and control information from the core network, processes it through the full protocol stack (RRC → PDCP → RLC → MAC → PHY), and generates baseband IQ samples that are serialised and transmitted to the RE via CPRI. In the reverse direction, the REC receives uplink IQ samples from the RE, performs demodulation, decoding, and protocol processing, then forwards user data to the core network. The CPRI interface between REC and RE typically carries uncompressed IQ samples at very high data rates (e.g., 24.3 Gbps for a 100 MHz MIMO carrier). In 5G, the REC functions are distributed between the O-DU and O-CU, and the fronthaul interface evolves to eCPRI with compressed IQ or other split options.
Use Cases
C-RAN centralised baseband processing, CPRI-based fronthaul deployments, traditional macro cell base station architecture, migration planning from CPRI REC/RE to eCPRI O-DU/O-RU, and base station capacity planning.
3GPP / Standards Reference
CPRI Specification v7.0, O-RAN Alliance fronthaul specifications, 3GPP TS 38.401 (NG-RAN architecture)
Related Terms
BBU | CPRI | C-RAN | O-RU / O-DU / O-CU | Fronthaul
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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.
