RNTI Values
In 5G NR, RNTI (Radio Network Temporary Identifier) values are super important for figuring out different types of communication in the network. They help us tell apart control and data transmissions, so we can manage resources efficiently. Each RNTI has a specific job, like signaling (e.g., RA-RNTI for random access), data transmission (e.g., C-RNTI for UE-specific communication), or even special cases like sidelink communications (e.g., SL-RNTI). RNTIs are written in hexadecimal and are given out on the fly based on what the network needs, so they’re flexible and can grow with the network. They’re key to making 5G networks strong and diverse, supporting things like super-fast mobile broadband, huge IoT, and super-reliable low-latency communication.
- RNTI Function: Identifies different types of communication contexts within a 5G NR network.
- RNTI Types: RA-RNTI (random access), C-RNTI (UE-specific communication), SL-RNTI (sidelink communications).
- RNTI Allocation: Dynamically allocated in hexadecimal format to ensure flexibility and scalability.
| Value (Hexadecimal) | RNTI |
|---|---|
| 0000 | N/A |
| 0001–FFF2 | RA-RNTI, MSGB-RNTI, Temporary C-RNTI, C-RNTI, CI-RNTI, MCS-C-RNTI, CS-RNTI, TPC-PUCCH-RNTI, TPC-PUSCH-RNTI, TPC-SRS-RNTI, INT-RNTI, SFI-RNTI, SP-CSI-RNTI, PS-RNTI, SL-RNTI, SL-CS-RNTI, SL Semi-Persistent Scheduling V-RNTI, AI-RNTI, G-RNTI, G-CS-RNTI, and CG-SDT-CS-RNTI |
| FFF3–FFFB | Reserved |
| FFFC | PEI-RNTI |
| FFFD | MCCH-RNTI |
| FFFE | P-RNTI |
| FFFF | SI-RNTI |
RNTI usage
| RNTI | Usage | Transport Channel | Logical Channel |
|---|---|---|---|
| P-RNTI | Paging and System Information change notification | PCH | PCCH |
| SI-RNTI | Broadcast of System Information | DL-SCH | BCCH |
| RA-RNTI | Random Access Response | DL-SCH | N/A |
| MSGB-RNTI | Random Access Response for 2-step RA type | DL-SCH | CCCH, DCCH, DTCH |
| Temporary C-RNTI | Contention Resolution (when no valid C-RNTI is available) | DL-SCH | CCCH, DCCH, DTCH |
| Temporary C-RNTI | Msg3 transmission | UL-SCH | CCCH, DCCH, DTCH |
| C-RNTI, MCS-C-RNTI | Dynamically scheduled unicast transmission | UL-SCH | DCCH, DTCH |
| C-RNTI | Dynamically scheduled unicast transmission | DL-SCH | CCCH, DCCH, DTCH |
| MCS-C-RNTI | Dynamically scheduled unicast transmission | DL-SCH | DCCH, DTCH |
| C-RNTI | Triggering of PDCCH ordered random access | N/A | N/A |
| C-RNTI | Dynamically scheduled PTP retransmission for initial PTM transmission for multicast MBS. | DL-SCH | MTCH |
| CG-SDT-CS-RNTI | Dynamically scheduled unicast transmission (retransmission) | UL-SCH | CCCH, DCCH, DTCH |
| CS-RNTI | Configured scheduled unicast transmission (activation, reactivation and retransmission) | DL-SCH, UL-SCH | DCCH, DTCH |
| CS-RNTI | Configured scheduled unicast transmission (deactivation) | N/A | N/A |
| CS-RNTI | Configured scheduled unicast transmission (PTP retransmission for initial PTM transmission) | DL-SCH | MTCH |
| CS-RNTI | Configured scheduled unicast transmission (MBS SPS deactivation) | N/A | N/A |
| G-CS-RNTI | Configured scheduled multicast transmission (activation, reactivation and retransmission) | DL-SCH | MTCH |
| G-CS-RNTI | Configured scheduled multicast transmission (deactivation) | N/A | N/A |
| TPC-PUCCH-RNTI | PUCCH power control | N/A | N/A |
| TPC-PUSCH-RNTI | PUSCH power control | N/A | N/A |
| TPC-SRS-RNTI | SRS trigger and power control | N/A | N/A |
| INT-RNTI | Indication pre-emption in DL | N/A | N/A |
| SFI-RNTI | Slot Format Indication on the given cell | N/A | N/A |
| SP-CSI-RNTI | Activation of Semi-persistent CSI reporting on PUSCH | N/A | N/A |
| CI-RNTI | Cancellation indication in UL | N/A | N/A |
| PS-RNTI | DCP to indicate whether to start drx-onDurationTimer for associated DRX cycle | N/A | N/A |
| SL-RNTI | Dynamically scheduled sidelink transmission | SL-SCH | SCCH, STCH |
| SL-CS-RNTI | Configured scheduled sidelink transmission (activation, reactivation and retransmission) | SL-SCH | SCCH, STCH |
| SL-CS-RNTI | Configured scheduled sidelink transmission (deactivation) | N/A | N/A |
| SL Semi-Persistent Scheduling V-RNTI (NOTE 2) | Semi-Persistently scheduled sidelink transmission for V2X sidelink communication (activation, reactivation and retransmission) | SL-SCH | STCH |
| SL Semi-Persistent Scheduling V-RNTI (NOTE 2) | Semi-Persistently scheduled sidelink transmission for V2X sidelink communication (deactivation) | N/A | N/A |
| AI-RNTI | Availability indication on the given cell | N/A | N/A |
| G-RNTI | Dynamically scheduled MBS PTM transmission | DL-SCH | MTCH |
| MCCH-RNTI | Dynamically scheduled MCCH signalling and MCCH change notification | DL-SCH | MCCH |
| PEI-RNTI | Paging Early Indication | N/A | N/A |
- NOTE 1: The usage of MCS-C-RNTI is equivalent to that of C-RNTI in MAC procedures (except for the C-RNTI MAC CE).
- NOTE 2: The MAC entity uses SL Semi-Persistent Scheduling V-RNTI to control semi-persistently scheduled sidelink transmission on SL-SCH for V2X sidelink communication as specified in clause 5.14.1.1 of TS 36.321
- NOTE 3: The usage of CG-SDT-CS-RNTI is equivalent to that of CS-RNTI when there is an CG-SDT procedure ongoing.
RNTI stands for Radio Network Temporary Identifier. It is used to uniquely identify User Equipment (UE) or specific communication contexts in the 5G network.
RNTI values are crucial for managing resources, ensuring efficient signaling, and maintaining communication sessions between the network and devices.
Common types include:
• RA-RNTI: Used during random access procedures.
• C-RNTI: Identifies a specific UE for dedicated communication.
• SL-RNTI: Used for sidelink communication in device-to-device (D2D) scenarios.
No, RNTI values are dynamically assigned and released based on network conditions and the state of the communication session.
RNTI values are typically represented in hexadecimal format, with each range designated for specific purposes, such as signaling or data transmission.
No, RNTI values are unique within a specific context to avoid conflicts and ensure reliable communication.
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