* 5G NR 协议栈：Control Plane和User Plane。
* CP: L1: PHY(Physical), L2:MAC(Medium Access Control), RLC(Radio Link Control), PDCP(Packet Data Convergence Protocol), L3:RRC(Radio Resource Control), NAS(Non-Access Stratum)
* UP: L1: PHY(Physical), L2:MAC(Medium Access Control), RLC(Radio Link Control), PDCP(Packet Data Convergence Protocol), SDAP(Service Data Adaptation Protocol)
* Uu: the radio interface between the UTRAN (UMTS Terrestrial Radio Access Network) and the UE.
* eCPRI(evolved Common Public Radio Interface): it is fronthaul interface between the RU (Radio Unit) and the DU(Distributed Uint). 减少天线和AAU之间的馈线。
* F1: it is middlehaul interface between the CU and the DU.
* NG: it is backhaul interface between the CU and the AMF.
* Xn: it is the backhaul interface between NG-RAN nodes.
注：TS 38.300: 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; NR; NR and NG-RAN Overall Description