ETSI TS 138 321 V16.11.0 (2023-01)

5G; NR; Medium Access Control (MAC) protocol specification (3GPP TS 38.321 version 16.11.0 Release 16)

RTS/TSGR-0238321vgb0

General Information

• Status: Not Published
• Technical Committee: 3GPP RAN 2 - Radio layer 2 specification and Radio layer 3 RR specification
• Current Stage: 12 - Citation in the OJ (auto-insert)
• Completion Date: 20-Jan-2023

Standards Content (Sample)

ETSI TS 138 321 V16.11.0 (2023-01)






TECHNICAL SPECIFICATION
5G;
NR;
Medium Access Control (MAC) protocol specification
(3GPP TS 38.321 version 16.11.0 Release 16)

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3GPP TS 38.321 version 16.11.0 Release 16 1 ETSI TS 138 321 V16.11.0 (2023-01)

Reference
RTS/TSGR-0238321vgb0
Keywords
5G
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ETSI

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3GPP TS 38.321 version 16.11.0 Release 16 2 ETSI TS 138 321 V16.11.0 (2023-01)
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ETSI

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3GPP TS 38.321 version 16.11.0 Release 16 3 ETSI TS 138 321 V16.11.0 (2023-01)
Contents
Intellectual Property Rights . 2
Legal Notice . 2
Modal verbs terminology . 2
Foreword . 7
1 Scope . 8
2 References . 8
3 Definitions, symbols and abbreviations . 9
3.1 Definitions . 9
3.2 Abbreviations . 10
4 General . 11
4.1 Introduction . 11
4.2 MAC architecture . 11
4.2.1 General . 11
4.2.2 MAC Entities . 11
4.3 Services . 13
4.3.1 Services provided to upper layers . 13
4.3.2 Services expected from physical layer . 13
4.4 Functions . 13
4.5 Channel structure . 14
4.5.1 General . 14
4.5.2 Transport Channels . 14
4.5.3 Logical Channels . 14
4.5.4 Mapping of Transport Channels to Logical Channels . 15
4.5.4.1 General . 15
4.5.4.2 Uplink mapping . 15
4.5.4.3 Downlink mapping . 15
4.5.4.4 Sidelink mapping . 15
5 MAC procedures . 16
5.1 Random Access procedure . 16
5.1.1 Random Access procedure initialization . 16
5.1.1a Initialization of variables specific to Random Access type . 20
5.1.2 Random Access Resource selection . 22
5.1.2a Random Access Resource selection for 2-step RA type . 24
5.1.3 Random Access Preamble transmission . 26
5.1.3a MSGA transmission . 27
5.1.4 Random Access Response reception. 29
5.1.4a MSGB reception and contention resolution for 2-step RA type . 31
5.1.5 Contention Resolution . 34
5.1.6 Completion of the Random Access procedure . 36
5.2 Maintenance of Uplink Time Alignment . 36
5.3 DL-SCH data transfer . 37
5.3.1 DL Assignment reception . 37
5.3.2 HARQ operation . 39
5.3.2.1 HARQ Entity. 39
5.3.2.2 HARQ process . 39
5.3.3 Disassembly and demultiplexing . 40
5.4 UL-SCH data transfer . 41
5.4.1 UL Grant reception . 41
5.4.2 HARQ operation . 44
5.4.2.1 HARQ Entity. 44
5.4.2.2 HARQ process . 47
5.4.3 Multiplexing and assembly . 49
5.4.3.1 Logical Channel Prioritization . 49
ETSI

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3GPP TS 38.321 version 16.11.0 Release 16 4 ETSI TS 138 321 V16.11.0 (2023-01)
5.4.3.1.1 General . 49
5.4.3.1.2 Selection of logical channels . 49
5.4.3.1.3 Allocation of resources . 50
5.4.3.2 Multiplexing of MAC Control Elements and MAC SDUs . 52
5.4.4 Scheduling Request. 52
5.4.5 Buffer Status Reporting . 55
5.4.6 Power Headroom Reporting . 57
5.4.7 Pre-emptive Buffer Status Reporting . 60
5.5 PCH reception . 60
5.6 BCH reception . 61
5.7 Discontinuous Reception (DRX) . 61
5.8 Transmission and reception without dynamic scheduling . 65
5.8.1 Downlink . 65
5.8.2 Uplink . 65
5.8.3 Sidelink . 67
5.9 Activation/Deactivation of SCells . 69
5.10 Activation/Deactivation of PDCP duplication. 71
5.11 MAC reconfiguration . 71
5.12 MAC Reset . 71
5.13 Handling of unknown, unforeseen and erroneous protocol data . 73
5.14 Handling of measurement gaps . 73
5.15 Bandwidth Part (BWP) operation . 73
5.15.1 Downlink and Uplink. 73
5.15.2 Sidelink . 76
5.16 SUL operation . 77
5.17 Beam Failure Detection and Recovery procedure . 78
5.18 Handling of MAC CEs . 80
5.18.1 General . 80
5.18.2 Activation/Deactivation of Semi-persistent CSI-RS/CSI-IM resource set . 80
5.18.3 Aperiodic CSI Trigger State Subselection . 80
5.18.4 Activation/Deactivation of UE-specific PDSCH TCI state . 81
5.18.5 Indication of TCI state for UE-specific PDCCH . 81
5.18.6 Activation/Deactivation of Semi-persistent CSI reporting on PUCCH . 81
5.18.7 Activation/Deactivation of Semi-persistent SRS and Indication of spatial relation of SP/AP SRS . 81
5.18.8 Activation/Deactivation of spatial relation of PUCCH resource . 82
5.18.9 Activation/Deactivation of semi-persistent ZP CSI-RS resource set . 82
5.18.10 Recommended Bit Rate . 82
5.18.11 Void . 83
5.18.12 Void . 83
5.18.13 Void . 83
5.18.14 Update of Pathloss Reference RS of SRS . 83
5.18.15 Update of Pathloss Reference RS of PUSCH . 83
5.18.16 Indication of spatial relation of SRS resource for a Serving Cell set . 83
5.18.17 Activation/Deactivation of Semi-Persistent Positioning SRS . 84
5.18.18 Timing offset adjustment for IAB . 84
5.18.19 Guard symbols for IAB . 84
5.19 Data inactivity monitoring . 85
5.20 Void . 85
5.21 LBT operation . 85
5.21.1 General . 85
5.21.2 LBT failure detection and recovery procedure . 85
5.22 SL-SCH Data transfer . 87
5.22.1 SL-SCH Data transmission . 87
5.22.1.1 SL Grant reception and SCI transmission . 87
5.22.1.2 TX resource (re-)selection check . 92
5.22.1.2a Re-evaluation and Pre-emption . 93
5.22.1.3 Sidelink HARQ operation . 94
5.22.1.3.1 Sidelink HARQ Entity . 94
5.22.1.3.1a Sidelink process . 95
5.22.1.3.2 PSFCH reception . 97
5.22.1.3.3 HARQ-based Sidelink RLF detection . 98
5.22.1.4 Multiplexing and assembly . 98
ETSI

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3GPP TS 38.321 version 16.11.0 Release 16 5 ETSI TS 138 321 V16.11.0 (2023-01)
5.22.1.4.0 General . 98
5.22.1.4.1 Logical channel prioritization . 98
5.22.1.4.1.1 General . 98
5.22.1.4.1.2 Selection of logical channels. 99
5.22.1.4.1.3 Allocation of sidelink resources . 100
5.22.1.4.2 Multiplexing of MAC Control Elements and MAC SDUs . 101
5.22.1.5 Scheduling Request . 101
5.22.1.6 Buffer Status Reporting . 101
5.22.1.7 CSI Reporting . 104
5.22.2 SL-SCH Data reception . 104
5.22.2.1 SCI reception. 104
5.22.2.2 Sidelink HARQ operation . 105
5.22.2.2.1 Sidelink HARQ Entity . 105
5.22.2.2.2 Sidelink process . 106
5.22.2.3 Disassembly and demultiplexing . 107
5.23 SL-BCH data transfer . 107
5.23.1 SL-BCH data transmission . 107
5.23.2 SL-BCH data reception . 107
6 Protocol Data Units, formats and parameters . 107
6.1 Protocol Data Units . 107
6.1.1 General . 107
6.1.2 MAC PDU (DL-SCH and UL-SCH except transparent MAC and Random Access Response) . 108
6.1.3 MAC Control Elements (CEs) . 110
6.1.3.1 Buffer Status Report MAC CEs . 110
6.1.3.2 C-RNTI MAC CE . 114
6.1.3.3 UE Contention Resolution Identity MAC CE . 114
6.1.3.4 Timing Advance Command MAC CE . 114
6.1.3.4a Absolute Timing Advance Command MAC CE . 115
6.1.3.5 DRX Command MAC CE . 115
6.1.3.6 Long DRX Command MAC CE . 115
6.1.3.7 Configured Grant Confirmation MAC CE . 115
6.1.3.8 Single Entry PHR MAC CE . 115
6.1.3.9 Multiple Entry PHR MAC CE . 117
6.1.3.10 SCell Activation/
...