5G • RAN
TC-RNTI
Temporary Cell RNTI
Temporary identifier assigned to a UE in Msg2 RAR used to scramble Msg3 and Msg4 during random access.
Technical Explanation
Because a connecting UE does not yet possess a C-RNTI, the gNodeB assigns a 16-bit Temporary C-RNTI (TC-RNTI) in Msg2 RAR. The UE scrambles Msg3 and decodes Msg4 using TC-RNTI. Once contention resolution succeeds, the TC-RNTI is promoted to become the UE's permanent C-RNTI.
Key Functions
- Assigned in Msg2 RAR to identify the UE during initial connection
- Scrambles Msg3 uplink transmission and Msg4 downlink decoding
- Promoted to permanent C-RNTI upon successful contention resolution
Specifications
3GPP TS 38.213, TS 38.321
Interfaces
Uu
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