Beam selection, refinement, and recovery

Monitoring and Switching Beams

Once an initial beam pair is established, the UE continuously monitors beam quality through L1-RSRP measurements on SSB and CSI-RS reference signals. When a neighboring beam shows better signal strength, the UE reports this improvement via PUCCH or a MAC Control Element. The gNB can then switch the serving beam using DCI signaling or a MAC CE command, both of which are significantly faster than RRC-based mobility procedures. This L1-based beam switching happens transparently to higher layers and keeps the data link optimized as the user moves.