NR; Radio Resource Control (RRC); Protocol specification

Grounded in the official 3GPP Scope excerpt

TS 38.331 specifies the Radio Resource Control (RRC) protocol for the UE-to-NG-RAN radio interface. Beyond the base UE-gNB air interface, it covers radio-related information carried in transparent containers for inter-gNB handover, inter-RAT handover (to/from other systems), and E-UTRA-NR Dual Connectivity (en-DC) between source eNB and target gNB. The spec also governs RRC configuration for IAB-node-to-parent-node and NCR-node-to-gNB radio interfaces. A RAN or core engineer would open this document when implementing or troubleshooting any RRC-layer behavior: decoding RRC messages and IEs at the UE or gNB, verifying transparent container contents exchanged during handover or en-DC setup, understanding configuration signaling for IAB or NCR nodes, or resolving ambiguities in protocol state machines and information element definitions. It is the definitive reference any time a question touches NR RRC signaling on the Uu interface or its associated inter-node radio containers.

Generated 10/14/2026 · cached for 90 days