3 Definitions and abbreviations
36.3213GPPEvolved Universal Terrestrial Radio Access (E-UTRA)Medium Access Control (MAC) protocol specificationRelease 17TS
3.1 Definitions
For the purposes of the present document, the terms and definitions given in TR 21.905 [1] and the following apply. A term defined in the present document takes precedence over the definition of the same term, if any, in TR 21.905 [1].
Active Time: Time related to DRX operation, as defined in clause 5.7, during which the MAC entity monitors the PDCCH.
mac-ContentionResolutionTimer: Specifies the number of consecutive subframe(s) during which the MAC entity shall monitor the PDCCH after Msg3 is transmitted.
DRX Cycle: Specifies the periodic repetition of the On Duration followed by a possible period of inactivity (see figure 3.1-1 below).
Figure 3.1-1: DRX Cycle
drx-InactivityTimer: Except for NB-IoT UEs, BL UEs or UEs in enhanced coverage, it specifies the number of consecutive PDCCH-subframe(s) after the subframe in which a PDCCH indicates an initial UL, DL or SL user data transmission for this MAC entity. For NB-IoT UEs, it specifies the number of consecutive PDCCH-subframe(s) after the subframe in which the HARQ RTT timer or UL HARQ RTT timer expires. For BL UEs or UEs in enhanced coverage, it specifies the number of consecutive PDCCH-subframe(s) following the subframe containing the last repetition of the PDCCH reception that indicates an initial UL or DL user data transmission for this MAC entity.
drx-RetransmissionTimer: Specifies the maximum number of consecutive PDCCH-subframe(s) until a DL retransmission is received.
drx-RetransmissionTimerShortTTI: Specifies the maximum number of consecutive TTI(s) until a DL retransmission is received for HARQ processes scheduled using short TTI.
drxShortCycleTimer: Specifies the number of consecutive subframe(s) the MAC entity shall follow the Short DRX cycle.
drxStartOffset: Specifies the subframe where the DRX Cycle starts.
drx-ULRetransmissionTimer: Specifies the maximum number of consecutive PDCCH-subframe(s) until a grant for UL retransmission or the HARQ feedback is received.
drx-ULRetransmissionTimeShortTTI: Specifies the maximum number of consecutive TTI(s) until a grant for UL retransmission is received for HARQ processes scheduled using short TTI.
Early Data Transmission: Allows one uplink data transmission optionally followed by one downlink data transmission during the random access procedure as specified in TS 36.300 [20]. The S1 connection is established or resumed upon reception of the uplink data and may be released or suspended along with the transmission of the downlink data. Early data transmission refers to both CP-EDT and UP-EDT.
HARQ information: HARQ information for DL-SCH or for UL-SCH transmissions consists of New Data Indicator (NDI), Transport Block (TB) size. For DL-SCH transmissions and for asynchronous UL HARQ and for autonomous UL HARQ, the HARQ information also includes HARQ process ID, except for UEs in NB-IoT configured with a single HARQ process for which this information is not present. For UL-SCH transmission the HARQ information also includes Redundancy Version (RV). In case of spatial multiplexing on DL-SCH the HARQ information comprises a set of NDI and TB size for each transport block. HARQ information for SL-SCH and SL-DCH transmissions consists of TB size only.
HARQ RTT Timer: This parameter specifies the minimum amount of subframe(s) before a DL assignment for HARQ retransmission is expected by the MAC entity.
Msg3: Message transmitted on UL-SCH containing a C-RNTI MAC CE or a CCCH SDU optionally multiplexed with DTCH for the UP-EDT, submitted from upper layer and associated with the UE Contention Resolution Identity, as part of a random access procedure.
NB-IoT: NB-IoT allows access to network services via E-UTRA with a channel bandwidth limited to 200 kHz.
NB-IoT UE: A UE that uses NB-IoT.
NR sidelink communication: AS functionality enabling at least V2X Communication as defined in TS 23.287 [23], between two or more nearby UEs, using NR technology but not traversing any network node.
Non-terrestrial networks: An E-UTRAN consisting of eNBs, which provide non-terrestrial LTE access to UEs by means of an NTN payload embarked on a space-borne NTN vehicle and an NTN Gateway.
onDurationTimer: Specifies the number of consecutive PDCCH-subframe(s) at the beginning of a DRX Cycle.
PDCCH: Refers to the PDCCH (see TS 36.211 [7]), EPDCCH (in subframes when configured), MPDCCH (see TS 36.213 [2]), for an RN with R-PDCCH configured and not suspended, to the R-PDCCH, for NB-IoT to the NPDCCH or for short TTI to SPDCCH.
PDCCH period (pp): Refers to the interval between the start of two consecutive PDCCH occasions and depends on the currently used PDCCH search space, as specified in TS 36.213 [2]. A PDCCH occasion is the start of a search space and is defined by subframe k0 as specified in clause 16.6 of TS 36.213 [2]. The calculation of number of PDCCH-subframes for the timer configured in units of a PDCCH period is done by multiplying the number of PDCCH periods with npdcch-NumRepetitions-RA when the UE uses the common search space or by npdcch-NumRepetitions when the UE uses the UE specific search space. When counting a timer whose length is calculated in PDCCH-subframes, the UE shall include PDCCH-subframes that will be dropped or not required to be monitored as specified in clause 16.6 of TS 36.213 [2]. The calculation of number of subframes for the timer configured in units of a PDCCH period is done by multiplying the number of PDCCH periods with duration between two consecutive PDCCH occasions.
PDCCH-subframe: Refers to a subframe with PDCCH. This represents the union over PDCCH-subframes for all serving cells excluding cells configured with cross carrier scheduling for both uplink and downlink, as specified in TS 36.331 [8]; except if the UE is not capable of simultaneous reception and transmission in the aggregated cells where this instead represents the PDCCH-subframes of the SpCell.
– For FDD serving cells, all subframes represent PDCCH-subframes, unless specified otherwise in this clause.
– For TDD serving cells, all downlink subframes and subframes including DwPTS of the TDD UL/DL configuration indicated by tdd-Config, as specified in TS 36.331 [8] of the cell represent PDCCH-subframes, unless specified otherwise in this clause.
– For serving cells operating according to Frame structure Type 3, all subframes represent PDCCH-subframes.
– For RNs with an RN subframe configuration configured and not suspended, in its communication with the E-UTRAN, all downlink subframes configured for RN communication with the E-UTRAN represent PDCCH-subframes.
– For SC-PTM reception on an FDD cell, all subframes except MBSFN subframes represent PDCCH-subframes, unless specified otherwise in this clause.
– For SC-PTM reception on a TDD cell, all downlink subframes and subframes including DwPTS of the TDD UL/DL configuration indicated by tdd-Config, as specified in TS 36.331 [8] of the cell except MBSFN subframes represent PDCCH-subframes, unless specified otherwise in this clause.
– For BL UE or UE in enhanced coverage, all subframes in which the UE is required to monitor MPDCCH represent PDCCH-subframes among all valid subframes regardless of whether the subframe is dropped, see clause 9.1.5 of TS 36.213 [2].
– For NB-IoT UE, all subframes that are part of the NPDCCH search space represent PDCCH-subframes among all NB-IoT downlink subframes, including those which the UE is not required to monitor as specified in clause 16.6 of TS 36.213 [2].
PDSCH: Refers to subframe-PDSCH/slot-PDSCH/subslot-PDSCH or for NB-IoT to NPDSCH.
PRACH: Refers to PRACH or for NB-IoT to NPRACH.
PRACH Resource Index: The index of a PRACH within a system frame, see TS 36.211 [7]
Primary Timing Advance Group: Timing Advance Group containing the SpCell.
PUCCH SCell: An SCell configured with PUCCH/SPUCCH.
PUSCH: Refers to subframe-PUSCH/slot-PUSCH/subslot-PUSCH or for NB-IoT to NPUSCH.
ra-PRACH-MaskIndex: Defines in which PRACHs within a system frame the MAC entity can transmit a Random Access Preamble (see clause 7.3).
RA-RNTI: The Random Access RNTI is used on the PDCCH when Random Access Response messages are transmitted. It unambiguously identifies which time-frequency resource was utilized by the MAC entity to transmit the Random Access preamble.
SC Period: Sidelink Control period, the time period consisting of transmission of SCI and its corresponding data.
SCI: The Sidelink Control Information contains the sidelink scheduling information such as resource block assignment, modulation and coding scheme, Group Destination ID (for sidelink communication) and PPPP (for V2X sidelink communication), see TS 36.212 [5].
Secondary Timing Advance Group: Timing Advance Group not containing the SpCell. A Secondary Timing Advance Group contains at least one Serving Cell with an UL configured.
Serving Cell: A Primary or a Secondary Cell, see TS 36.331 [8].
Short Processing Time: For 1 ms TTI length, the operation with short processing time in UL data transmission and DL data reception.
Short TTI: TTI length based on a slot or a subslot.
Sidelink: UE to UE interface for sidelink communication, sidelink discovery and V2X sidelink communication. The sidelink corresponds to the PC5 interface as defined in TS 23.303 [13] for sidelink communication and sidelink discovery, and as defined in TS 23.285 [14] for V2X sidelink communication.
Sidelink communication: AS functionality enabling ProSe Direct Communication as defined in TS 23.303 [13], between two or more nearby UEs, using E-UTRA technology but not traversing any network node.
Sidelink Discovery Gap for Reception: Time period during which the UE does not receive any channels in DL from any serving cell, except during random access procedure.
Sidelink Discovery Gap for Transmission: Time period during which the UE prioritizes transmission of sidelink discovery and associated procedures e.g. re-tuning and synchronisation over transmission of channels in UL, if they occur in the same subframe, except during random access procedure.
Special Cell: For Dual Connectivity operation the term Special Cell refers to the PCell of the MCG or the PSCell of the SCG, otherwise the term Special Cell refers to the PCell.
Timing Advance Group: A group of Serving Cells that is configured by RRC and that, for the cells with an UL configured, using the same timing reference cell and the same Timing Advance value.
Transmission using PUR: Allows one uplink data transmission using preconfigured uplink resource from RRC_IDLE mode as specified in TS 36.300 [9]. Transmission using PUR refers to both CP transmission using PUR and UP transmission using PUR.
UE-eNB RTT: For non-terrestrial networks, the sum of the UE’s Timing Advance value (see TS 36.211 [7], clause 8.1) and k_Mac in units of subframe, not rounded or truncated toward an integer number of subframes.
UL HARQ RTT Timer: This parameter specifies the minimum amount of subframe(s) before a UL HARQ retransmission grant is expected by the MAC entity.
V2X sidelink communication: AS functionality enabling V2X Communication as defined in TS 23.285 [14], between nearby UEs, using E-UTRA technology but not traversing any network node.
NOTE: A timer is running once it is started, until it is stopped or until it expires; otherwise it is not running. A timer can be started if it is not running or restarted if it is running. A Timer is always started or restarted from its initial value.
3.2 Abbreviations
For the purposes of the present document, the abbreviations given in TR 21.905 [1] and the following apply. An abbreviation defined in the present document takes precedence over the definition of the same abbreviation, if any, in TR 21.905 [1].
AS Access Stratum
AUL Autonomous Uplink
BL Bandwidth reduced Low complexity
BR Bandwidth Reduced
BSR Buffer Status Report
C-RNTI Cell RNTI
CBR Channel Busy Ratio
CC-RNTI Common Control RNTI
CG Cell Group
CQI Channel Quality Indicator
CRI CSI-RS Resource Indicator
CSI Channel State Information
DAPS Dual Active Protocol Stack
DCQR Downlink Channel Quality Report
DRB Data Radio Bearer
EDT Early Data Transmission
eIMTA Enhanced Interference Management and Traffic Adaptation
eIMTA-RNTI Enhanced Interference Management and Traffic Adaptation – RNTI
E-UTRA Evolved UMTS Terrestrial Radio Access
E-UTRAN Evolved UMTS Terrestrial Radio Access Network
G-RNTI Group RNTI
H-SFN Hyper SFN
MAC Medium Access Control
MCG Master Cell Group
M-RNTI MBMS RNTI
MPDCCH MTC Physical Downlink Control Channel
LCG Logical Channel Group
NB-IoT Narrow Band Internet of Things
NPDCCH Narrowband Physical Downlink Control Channel
NPDSCH Narrowband Physical Downlink Shared channel
NPRACH Narrowband Physical Random Access Control Channel
NPUSCH Narrowband Physical Uplink Shared channel
PCell Primary Cell
PSCell Primary Secondary Cell
PHR Power Headroom Report
PMI Precoding Matrix Index
PPPP ProSe Per-Packet Priority
P-RNTI Paging RNTI
ProSe Proximity-based Services
pTAG Primary Timing Advance Group
PTI Precoding Type Indicator
PUR Preconfigured Uplink Resource
RA-RNTI Random Access RNTI
RAI Release Assistance Indication
RI Rank Indicator
RN Relay Node
RNTI Radio Network Temporary Identifier
SCell Secondary Cell
SC-FDM Single-Carrier Frequency Division Multiplexing
SCG Secondary Cell Group
SCI Sidelink Control Information
SC-N-RNTI Single Cell Notification RNTI
SC-PTM Single Cell Point to Multipoint
SC-RNTI Single Cell RNTI
SI-RNTI System Information RNTI
SL Sidelink
SL-RNTI Sidelink RNTI
SL-V-RNTI Sidelink V2X RNTI
SR Scheduling Request
SRS Sounding Reference Symbols
SRS-TPC-RNTI Sounding Reference Symbols-Transmit Power Control-RNTI
SpCell Special Cell
sTAG Secondary Timing Advance Group
sTTI Slot or subslot TTI
TAG Timing Advance Group
TB Transport Block
TPC-PUCCH-RNTI Transmit Power Control-Physical Uplink Control Channel-RNTI
TPC-PUSCH-RNTI Transmit Power Control-Physical Uplink Shared Channel-RNTI
V2X Vehicle-to-Everything