ETSI TS 136 321 V14.11.0 (2019-07)

LTE; Evolved Universal Terrestrial Radio Access (E-UTRA); Medium Access Control (MAC) protocol specification (3GPP TS 36.321 version 14.11.0 Release 14)

RTS/TSGR-0236321veb0

General Information

• Status: Published
• Publication Date: 24-Jul-2019
• Technical Committee: 3GPP RAN 2 - Radio layer 2 specification and Radio layer 3 RR specification
• Current Stage: 12 - Completion
• Completion Date: 25-Jul-2019

Standards Content (Sample)

TECHNICAL SPECIFICATION
LTE;
Evolved Universal Terrestrial Radio Access (E-UTRA);
Medium Access Control (MAC) protocol specification
(3GPP TS 36.321 version 14.11.0 Release 14)

3GPP TS 36.321 version 14.11.0 Release 14 1 ETSI TS 136 321 V14.11.0 (2019-07)

Reference
RTS/TSGR-0236321veb0
Keywords
LTE
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ETSI
3GPP TS 36.321 version 14.11.0 Release 14 2 ETSI TS 136 321 V14.11.0 (2019-07)
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Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 6
1 Scope . 7
2 References . 7
3 Definitions and abbreviations . 8
3.1 Definitions . 8
3.2 Abbreviations . 10
4 General . 11
4.1 Introduction . 11
4.2 MAC architecture . 11
4.2.1 MAC Entities . 12
4.3 Services . 14
4.3.1 Services provided to upper layers . 14
4.3.2 Services expected from physical layer . 14
4.4 Functions . 14
4.5 Channel structure . 15
4.5.1 Transport Channels . 15
4.5.2 Logical Channels . 16
4.5.3 Mapping of Transport Channels to Logical Channels . 16
4.5.3.1 Uplink mapping . 16
4.5.3.2 Downlink mapping . 17
4.5.3.3 Sidelink mapping . 18
5 MAC procedures . 18
5.1 Random Access procedure . 18
5.1.1 Random Access Procedure initialization . 18
5.1.2 Random Access Resource selection . 21
5.1.3 Random Access Preamble transmission . 23
5.1.4 Random Access Response reception. 24
5.1.5 Contention Resolution . 27
5.1.6 Completion of the Random Access procedure . 29
5.2 Maintenance of Uplink Time Alignment . 29
5.3 DL-SCH data transfer . 30
5.3.1 DL Assignment reception . 30
5.3.2 HARQ operation . 32
5.3.2.1 HARQ Entity. 32
5.3.2.2 HARQ process . 33
5.3.3 Disassembly and demultiplexing . 34
5.4 UL-SCH data transfer . 34
5.4.1 UL Grant reception . 34
5.4.2 HARQ operation . 36
5.4.2.1 HARQ entity . 36
5.4.2.2 HARQ process . 38
5.4.3 Multiplexing and assembly . 40
5.4.3.1 Logical channel prioritization . 40
5.4.3.2 Multiplexing of MAC Control Elements and MAC SDUs . 41
5.4.4 Scheduling Request. 42
5.4.5 Buffer Status Reporting . 42
5.4.5a Data Volume and Power Headroom Reporting . 44
5.4.6 Power Headroom Reporting . 44
5.5 PCH reception . 46
5.6 BCH reception . 47
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5.7 Discontinuous Reception (DRX) . 47
5.7a Discontinuous Reception (DRX) for SC-PTM . 50
5.8 MAC reconfiguration . 50
5.9 MAC Reset . 51
5.10 Semi-Persistent Scheduling . 51
5.10.1 Downlink . 52
5.10.2 Uplink . 52
5.11 Handling of unknown, unforeseen and erroneous protocol data . 53
5.12 MCH reception . 53
5.13 Activation/Deactivation of SCells . 53
5.14 SL-SCH Data transfer . 55
5.14.1 SL-SCH Data transmission . 55
5.14.1.1 SL Grant reception and SCI transmission . 55
5.14.1.2 Sidelink HARQ operation . 60
5.14.1.2.1 Sidelink HARQ Entity . 60
5.14.1.2.2 Sidelink process . 61
5.14.1.3 Multiplexing and assembly . 62
5.14.1.3.1 Logical channel prioritization . 62
5.14.1.3.2 Multiplexing of MAC SDUs . 62
5.14.1.4 Buffer Status Reporting . 62
5.14.2 SL-SCH Data reception . 64
5.14.2.1 SCI reception. 64
5.14.2.2 Sidelink HARQ operation . 65
5.14.2.2.1 Sidelink HARQ Entity . 65
5.14.2.2.2 Sidelink process . 65
5.14.2.3 Disassembly and demultiplexing . 66
5.15 SL-DCH data transfer . 66
5.15.1 SL-DCH data transmission . 66
5.15.1.1 Resource allocation . 66
5.15.1.2 Sidelink HARQ operation . 66
5.15.1.2.1 Sidelink HARQ Entity . 66
5.15.1.2.2 Sidelink process . 67
5.15.2 SL-DCH data reception . 67
5.15.2.1 Sidelink HARQ operation . 67
5.15.2.1.1 Sidelink HARQ Entity . 67
5.15.2.1.2 Sidelink process . 68
5.16 SL-BCH data transfer . 68
5.16.1 SL-BCH data transmission . 68
5.16.2 SL-BCH data reception . 69
5.17 Data inactivity monitoring . 69
5.18 Recommended Bit Rate . 69
5.19 Activation/Deactivation of CSI-RS resources . 70
5.20 Preallocated uplink grant . 70
5.21 SC-PTM Stop Indication . 70
6 Protocol Data Units, formats and parameters . 71
6.1 Protocol Data Units . 71
6.1.1 General . 71
6.1.2 MAC PDU (DL-SCH and UL-SCH except transparent MAC and Random Access Response, MCH) . 71
6.1.3 MAC Control Elements . 72
6.1.3.1 Buffer Status Report MAC Control Elements . 72
6.1.3.1a Sidelink BSR MAC Control Elements . 75
6.1.3.2 C-RNTI MAC Control Element . 76
6.1.3.3 DRX Command MAC Control Element . 77
6.1.3.4 UE Contention Resolution Identity MAC Control Element . 77
6.1.3.5 Timing Advance Command MAC Control Element . 77
6.1.3.6 Power Headroom Report MAC Control Element . 78
6.1.3.6a Extended Power Headroom Report MAC Control Elements . 78
6.1.3.6b Dual Connectivity Power Headroom Report MAC Control Element . 81
6.1.3.7 MCH Scheduling Information MAC Control Element . 83
6.1.3.7a Extended MCH Scheduling Information MAC Control Element . 84
6.1.3.8 Activation/Deactivation MAC Control Elements . 84
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6.1.3.9 Long DRX Command MAC Control Element . 85
6.1.3.10 Data Volume and Power Headroom Report MAC Control Element . 85
6.1.3.11 SPS confirmation MAC Control Element . 86
6.1.3.12 SC-PTM Stop Indication MAC Control Element . 86
6.1.3.13 Recommended bit rate MAC Control Element . 86
6.1.3.14 Activation/Deactivation of CSI-RS resources MAC Control Element . 87
6.1.4 MAC PDU (transparent MAC) . 88
6.1.5 MAC PDU (Random Access Response) . 88
6.1.6 MAC PDU (SL-SCH) . 90
6.2 Formats and parameters . 92
6.2.1 MAC header for DL-SCH, UL-SCH and MCH. 92
6.2.2 MAC header for Random Access Response . 94
6.2.3 MAC payload for Random Access Response . 94
6.2.4 MAC header for SL-SCH . 94
7 Variables and constants . 96
7.1 RNTI values . 96
7.2 Backoff Parameter values . 97
7.3 PRACH Mask Index values. 99
7.4 Subframe_Offset values . 99
7.5 TTI_BUNDLE_SIZE value. 99
7.6 DELTA_PREAMBLE values . 99
7.7 HARQ RTT Timers . 100
7.8 DL_REPETITION_NUMBER value . 100
7.9 UL_REPETITION_NUMBER value . 100
Annex A (normative): Handling of measurement gaps . 101
Annex B (normative): Contention resolution for RACH access . 102
Annex C (informative): Intended UE behaviour for DRX Timers . 103
Annex D (informative): Change history . 104
History . 111

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Foreword
rd
This Technical Specification has been produced by the 3 Generation Partnership Project (3GPP).
The contents of the present document are subject to continuing work within the TSG and may change following formal
TSG approval. Should the TSG modify the contents of the present document, it will be re-released by the TSG with an
identifying change of release date and an increase in version number as follows:
Version x.y.z
where:
x the first digit:
1 presented to TSG for information;
2 presented to TSG for approval;
3 or greater indicates TSG approved document under change control.
y the second digit is incremented for all changes of substance, i.e. technical enhancements, corrections,
updates, etc.
z the third digit is incremented when editorial only changes have been incorporated in the document.
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3GPP TS 36.321 version 14.11.0 Release 14 7 ETSI TS 136 321 V14.11.0 (2019-07)
1 Scope
The present document specifies the E-UTRA MAC protocol.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
- References are either specific (identified by date of publication, edition number, version number, etc.) or
non-specific.
- For a specific reference, subsequent revisions do not apply.
- For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including
a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same
Release as the present document.
[1] 3GPP TR 21.905: "Vocabulary for 3GPP Specifications".
[2] 3GPP TS 36.213: "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Layer
Procedures".
[3] 3GPP TS 36.322: "Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Link Control
(RLC) protocol specification".
[4] 3GPP TS 36.323: "Evolved Universal Terrestrial Radio Access (E-UTRA); Packet Data
Convergence Protocol (PDCP) Specification".
[5] 3GPP TS 36.212: "Evolved Universal Terrestrial Radio Access (E-UTRA); Multiplexing and
channel coding".
[6] 3GPP TS 36.214: "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer;
Measurements".
[7] 3GPP TS 36.211: "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical Channels and
Modulation".
[8] 3GPP TS 36.331: "Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Resource
Control (RRC); Protocol specification".
[9] 3GPP TS 36.133: "Evolved Universal Terrestrial Radio Access (E-UTRA); Requirements for
support of radio resource management".
[10] 3GPP TS 36.101: "Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE)
radio transmission and reception".
[11] 3GPP TS 36.216: "Evolved Universal Terrestrial Radio Access (E-UTRA); Physical layer for
relaying operation".
[12] 3GPP TS 36.306: "Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE)
radio access capabilities".
[13] 3GPP TS 23.303: "Proximity-based services (ProSe); Stage 2".
[14] 3GPP TS 23.285: "Architecture enhancements for V2X services".
[15] 3GPP TS 24.386: "User Equipment (UE) to V2X control function; protocol aspects; Stage 3"
[16] 3GPP TS 26.114: "IP Multimedia Subsystem (IMS); Multimedia telephony; Media handling and
interaction".
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3 Definitions and abbreviations
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 subclause 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.
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 is received.
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, 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 CCCH SDU, 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.
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onDurationTimer: Specifies the number of consecutive PDCCH-subframe(s) at the beginning of a DRX Cycle.
PDCCH: Refers to the PDCCH, as specified in TS 36.211 [7], EPDCCH (in subframes when configured), MPDCCH,
as specified in TS 36.213 [2], for an RN with R-PDCCH configured and not suspended, to the R-PDCCH or, for NB-
IoT to the NPDCCH.
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. 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 subclause.
- 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 subclause.
- 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 subclause.
- 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 subclause.
- 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
subclause 9.1.5 of TS 36.213 [2].
PDSCH: Refers to 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, as specified in TS 36.211 [7]
Primary Timing Advance Group: Timing Advance Group containing the SpCell.
PUCCH SCell: An SCell configured with PUCCH.
PUSCH: Refers to 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 subclause 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.
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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), as specified in 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, as specified in TS 36.331 [8].
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.
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].
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
CQI Channel Quality Indicator
CRI CSI-RS Resource Indicator
CSI Channel State Information
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
MAC Medium Access Control
MCG Master Cell Group
M-RNTI MBMS RNTI
MPDCCH MTC Physical Downlink Control Channel
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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
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
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
4 General
4.1 Introduction
The objective is to describe the MAC architecture and the MAC entity from a functional point of view. Functionality
specified for the UE equally applies to the RN for functionality necessary for the RN. There is also functionality which
is only applicable to the RN, in which case the specification denotes the RN instead of the UE. RN-specific behaviour is
not applicable to the UE. For TDD operation, UE behaviour follows the TDD UL/DL configuration indicated by tdd-
Config unless specified otherwise.
4.2 MAC architecture
The description in this sub clause is a model and does not specify or restrict implementations.
RRC is in control of configuration of MAC.
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4.2.1 MAC Entities
E-UTRA defines two MAC entities; one in the UE and one in the E-UTRAN. These MAC entities handle the following
transport channels:
- Broadcast Channel (BCH);
- Downlink Shared Channel(s) (DL-SCH);
- Paging Channel (PCH);
- Uplink Shared Channel(s) (UL-SCH);
- Random Access Channel(s) (RACH);
- Multicast Channel(s) (MCH);
- Sidelink Broadcast Channel (SL-BCH);
- Sidelink Discovery Channel (SL-DCH);
- Sidelink Shared Channel (SL-SCH).
The exact functions performed by the MAC entities are different in the UE from those performed in the E-UTRAN.
The RN includes both types of MAC entities; one type for communication with UEs and one type for communication
with the E-UTRAN.
In Dual Connectivity, two MAC entities are configured in the UE: one for the MCG and one for the SCG. Each MAC
entity is configured by RRC with a serving cell supporting PUCCH transmission and contention based Random Access.
In this specification, the term SpCell refers to such cell, whereas the term SCell refers to other serving cells. The term
SpCell either refers to the PCell of the MCG or the PSCell of the SCG depending on if the MAC entity is associated to
the MCG or the SCG, respectively. A Timing Advance Group containin
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