- RNTI，Radio Network Temporary Identifier，是一种标识，两类用途：用于加扰DCI的CRC，UE只有使用正确的RNTI才能对接收到的消息解码；基站用于识别UE，UE发送的RRC message会携带自己专用的RNTI值。

- 5G中有多种类型的RNTI，可分为公共的和专用的两类：公共的RNTI取值是固定的，所有UE都一样（SI-RNTI,P-RNTI），专用的RNTI取值不是固定的，UE需要根据基站指示或者通过相关状态计算得到（如RA-RNTI是通过UE发送Preambles的RACH Occasion计算的）

为16bit，取值范围如下：

TS38.321 Table 7.1-1: RNTI values.

Value (hexa-decimal)

RNTI

-

0000

N/A

专用的

0001–FFF2

（1~65522）

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, SLCS-RNTI SL Semi-Persistent Scheduling V-RNTI, and AI-RNTI

-

FFF3–FFFD

（65523~65533）

Reserved

公共的

FFFE（65534）

P-RNTI

FFFF（65535）

SI-RNTI

TS38.321 Table 7.1-2: 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

Temporary C-RNTI

Contention Resolution (when no valid C-RNTI is available)

DL-SCH

CCCH, DCCH

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

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

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

SLCS-RNTI

Configured scheduled sidelink transmission (activation, reactivation and retransmission)

SL-SCH

SCCH, STCH

SLCS-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

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 [22].

-RA-RNTI：

RA-RNTI = 1 + s_id + 14 × t_id + 14 × 80 × f_id + 14 × 80 × 8 × ul_carrier_id

where s_id is the index of the first OFDM symbol of the PRACH occasion (0 ≤ s_id < 14), t_id is the index of the first slot of the PRACH occasion in a system frame (0 ≤ t_id < 80), where the subcarrier spacing to determine t_id is based on the value of μ specified in clause 5.3.2 in TS 38.211 [8], f_id is the index of the PRACH occasion in the frequency domain (0 ≤ f_id < 8), and ul_carrier_id is the UL carrier used for Random Access Preamble transmission (0 for NUL carrier, and 1 for SUL carrier).

- TC-RNTI:

UE由Msg2中获得TC-RNTI，位于MAC RAR中，UE获取到TC-RNTI后，用于发送Msg3和接收Msg4。

TS38.321，Figure 6.2.3-1: MAC RAR

-C- RNTI

UE接收到Msg4后，随机接入竞争解决成功，则UE将TC-RNTI升级为C-RNTI。