A Centralized Unit(CU) is a logical node in the radio base station of5G networks, the Next-Generation NodeB( gNB). The CU node supports various protocols such as Service Data Adaptation Protocol( SDAP), Packet Data Convergence Protocol( PDCP) and Radio Resource Control( RRC).
In addition, it forms the next-generation node (gNB) sublayer. The Centralized Unit controls one or more Distributed Units( DU) of Next-Generation Nodes. The CU unit terminates the fronthaul Higher Layer Split( HLS) interface connected to the Distributed Units (DUs).