ETSI TS 138 321 V17.0.0 (2022-05)

5G; NR; Medium Access Control (MAC) protocol specification (3GPP TS 38.321 version 17.0.0 Release 17)

RTS/TSGR-0238321vh00

General Information

• Status: Not Published
• Technical Committee: 3GPP RAN 2 - Radio layer 2 specification and Radio layer 3 RR specification
• Current Stage: 12 - Completion
• Completion Date: 09-May-2022

Standards Content (Sample)

ETSI TS 138 321 V17.0.0 (2022-05)






TECHNICAL SPECIFICATION
5G;
NR;
Medium Access Control (MAC) protocol specification
(3GPP TS 38.321 version 17.0.0 Release 17)

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3GPP TS 38.321 version 17.0.0 Release 17 1 ETSI TS 138 321 V17.0.0 (2022-05)

Reference
RTS/TSGR-0238321vh00
Keywords
5G
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ETSI

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3GPP TS 38.321 version 17.0.0 Release 17 2 ETSI TS 138 321 V17.0.0 (2022-05)
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ETSI

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3GPP TS 38.321 version 17.0.0 Release 17 3 ETSI TS 138 321 V17.0.0 (2022-05)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 8
1 Scope . 9
2 References . 9
3 Definitions, symbols and abbreviations . 10
3.1 Definitions . 10
3.2 Abbreviations . 11
4 General . 12
4.1 Introduction . 12
4.2 MAC architecture . 12
4.2.1 General . 12
4.2.2 MAC Entities . 13
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 . 15
4.5 Channel structure . 15
4.5.1 General . 15
4.5.2 Transport Channels . 15
4.5.3 Logical Channels . 16
4.5.4 Mapping of Transport Channels to Logical Channels . 16
4.5.4.1 General . 16
4.5.4.2 Uplink mapping . 16
4.5.4.3 Downlink mapping . 16
4.5.4.4 Sidelink mapping . 17
5 MAC procedures . 17
5.1 Random Access procedure . 17
5.1.1 Random Access procedure initialization . 17
5.1.1a Initialization of variables specific to Random Access type . 22
5.1.1b Selection of the set of Random Access resources applicable to the Random Access procedure . 25
5.1.1c Availability of Random Access resource partitions . 26
5.1.1d Random Access resources selection based on feature prioritization . 26
5.1.2 Random Access Resource selection . 27
5.1.2a Random Access Resource selection for 2-step RA type . 29
5.1.3 Random Access Preamble transmission . 31
5.1.3a MSGA transmission . 32
5.1.4 Random Access Response reception. 34
5.1.4a MSGB reception and contention resolution for 2-step RA type . 37
5.1.5 Contention Resolution . 39
5.1.6 Completion of the Random Access procedure . 42
5.2 Maintenance of Uplink Time Alignment . 42
5.3 DL-SCH data transfer . 44
5.3.1 DL Assignment reception . 44
5.3.2 HARQ operation . 46
5.3.2.1 HARQ Entity. 46
5.3.2.2 HARQ process . 47
5.3.3 Disassembly and demultiplexing . 48
5.4 UL-SCH data transfer . 48
5.4.1 UL Grant reception . 48
5.4.2 HARQ operation . 52
5.4.2.1 HARQ Entity. 52
ETSI

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3GPP TS 38.321 version 17.0.0 Release 17 4 ETSI TS 138 321 V17.0.0 (2022-05)
5.4.2.2 HARQ process . 56
5.4.3 Multiplexing and assembly . 58
5.4.3.1 Logical Channel Prioritization . 58
5.4.3.1.1 General . 58
5.4.3.1.2 Selection of logical channels . 58
5.4.3.1.3 Allocation of resources . 59
5.4.3.2 Multiplexing of MAC Control Elements and MAC SDUs . 60
5.4.4 Scheduling Request. 61
5.4.5 Buffer Status Reporting . 64
5.4.6 Power Headroom Reporting . 67
5.4.7 Pre-emptive Buffer Status Reporting . 70
5.4.8 Timing Advance Reporting . 71
5.5 PCH reception . 72
5.6 BCH reception . 72
5.7 Discontinuous Reception (DRX) . 72
5.7a Discontinuous Reception (DRX) for MBS Broadcast . 77
5.7b Discontinuous Reception (DRX) for MBS Multicast . 78
5.8 Transmission and reception without dynamic scheduling . 79
5.8.1 Downlink . 79
5.8.1a Downlink for Multicast . 80
5.8.2 Uplink . 80
5.8.3 Sidelink . 82
5.9 Activation/Deactivation of SCells . 84
5.10 Activation/Deactivation of PDCP duplication. 86
5.11 MAC reconfiguration . 87
5.12 MAC Reset . 87
5.12a MAC Reset for SCG deactivation . 88
5.13 Handling of unknown, unforeseen and erroneous protocol data . 89
5.14 Handling of measurement gaps . 89
5.15 Bandwidth Part (BWP) operation . 90
5.15.1 Downlink and Uplink. 90
5.15.2 Sidelink . 93
5.16 SUL operation . 94
5.17 Beam Failure Detection and Recovery procedure . 94
5.18 Handling of MAC CEs . 98
5.18.1 General . 98
5.18.2 Activation/Deactivation of Semi-persistent CSI-RS/CSI-IM resource set . 99
5.18.3 Aperiodic CSI Trigger State Subselection . 99
5.18.4 Activation/Deactivation of UE-specific PDSCH TCI state . 99
5.18.5 Indication of TCI state for UE-specific PDCCH . 99
5.18.6 Activation/Deactivation of Semi-persistent CSI reporting on PUCCH . 100
5.18.7 Activation/Deactivation of Semi-persistent SRS and Indication of spatial relation of SP/AP SRS . 100
5.18.8 Activation/Deactivation of spatial relation of PUCCH resource . 100
5.18.9 Activation/Deactivation of semi-persistent ZP CSI-RS resource set . 101
5.18.10 Recommended Bit Rate . 101
5.18.11 Void . 102
5.18.12 Void . 102
5.18.13 Void . 102
5.18.14 Update of Pathloss Reference RS of SRS . 102
5.18.15 Update of Pathloss Reference RS of PUSCH . 102
5.18.16 Indication of spatial relation of SRS resource for a Serving Cell set . 102
5.18.17 Activation/Deactivation of Semi-Persistent Positioning SRS . 102
5.18.18 Timing offset adjustments for IAB . 103
5.18.19 Guard symbols for IAB . 103
5.18.20 Positioning Measurement Gap Activation/Deactivation Command . 104
5.18.21 PPW Activation/Deactivation Command . 104
5.18.22 Update of PUCCH Power Control Set for multiple TRP PUCCH repetition . 104
5.18.23 Unified TCI States Activation/Deactivation MAC CE . 105
5.18.24 Update of Differential Koffset . 105
5.19 Data inactivity monitoring . 105
5.20 Void . 105
5.21 LBT operation . 105
ETSI

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3GPP TS 38.321 version 17.0.0 Release 17 5 ETSI TS 138 321 V17.0.0 (2022-05)
5.21.1 General . 105
5.21.2 LBT failure detection and recovery procedure . 106
5.22 SL-SCH Data transfer . 107
5.22.1 SL-SCH Data transmission . 107
5.22.1.1 SL Grant reception and SCI transmission . 107
5.22.1.2 TX resource (re-)selection check . 116
5.22.1.2a Re-evaluation and Pre-emption . 116
5.22.1.2b Re-selection for using a received resource conflict indication . 118
5.22.1.3 Sidelink HARQ operation . 118
5.22.1.3.1 Sidelink HARQ Entity . 118
5.22.1.3.1a Sidelink process . 120
5.22.1.3.2 PSFCH reception . 122
5.22.1.3.3 HARQ-based Sidelink RLF detection . 123
5.22.1.4 Multiplexing and assembly . 123
5.22.1.4.1 Logical channel prioritization . 124
5.22.1.4.1.1 General . 124
5.22.1.4.1.2 Selection of logical channels. 124
5.22.1.4.1.3 Allocation of sidelink resources . 126
5.22.1.4.2 Multiplexing of MAC Control Elements and MAC SDUs . 127
5.22.1.5 Scheduling Request . 127
5.22.1.6 Buffer Status Reporting . 127
5.22.1.7 CSI Reporting . 130
5.22.1.8 Sidelink DRX Command Indication . 130
5.22.1.9 IUC-Request transmission . 130
5.22.1.10 IUC-Information Reporting. 131
5.22.2 SL-SCH Data reception . 131
5.22.2.1 SCI reception. 131
5.22.2.2 Sidelink HARQ operation . 132
5.22.2.2.1 Sidelink HARQ Entity . 132
5.22.2.2.2 Sidelink process . 132
5.22.2.3 Disassembly and demultiplexing . 133
5.23 SL-BCH data transfer . 134
5.23.1 SL-BCH data transmission . 134
5.23.2 SL-BCH data reception .
...