Content for TS 38.331 Word version: 18.2.0

1… 4… 5… 5.2.2.4… 5.3… 5.3.3… 5.3.5… 5.3.5.5… 5.3.5.6… 5.3.5.7… 5.3.5.13… 5.3.5.17… 5.3.6… 5.3.8… 5.3.13… 5.3.14… 5.4… 5.5… 5.5.3… 5.5.4… 5.5.4.15… 5.5.4.23… 5.5.5… 5.5a… 5.7… 5.7.4… 5.7.8… 5.7.12… 5.8… 5.8.9… 5.8.9.2… 5.8.9.8… 5.8.10… 5.8.11… 5.9… 5.10… 6… 6.2.2… 6-2-2-23… 6-2-2-27… 6-2-2-43… 6-2-2-47… 6.3… 6.3.2… 6-3-2-27… 6-3-2-49… 6-3-2-73… 6-3-2-95… 6-3-2-108… 6-3-2-134… 6-3-2-162… 6-3-2-188… 6-3-2-213… 6-3-2-243… 6-3-2-271… 6-3-2-297… 6-3-2-341… 6.3.3… 6-3-3-25… 6-3-3-51… 6.3.4… 6.3.5… 6-3-5-25… 6.3.6… 6.4… 7… 9… 11… A… A.4… B…

5.8.9.2 Sidelink UE capability transfer 5.8.9.2.1 General 5.8.9.2.2 Initiation 5.8.9.2.3 Actions related to transmission of the UECapabilityEnquirySidelink by the UE 5.8.9.2.4 Actions related to reception of the UECapabilityEnquirySidelink by the UE 5.8.9.3 Sidelink radio link failure related actions 5.8.9.3a End-to-end PC5 connection failure related actions performed by L2 U2U Remote UE 5.8.9.3b End-to-end PC5 connection failure/release related actions performed by L2 U2U Relay UE 5.8.9.4 Sidelink common control information 5.8.9.4.1 General 5.8.9.4.2 Actions related to reception of MasterInformationBlockSidelink message 5.8.9.4.3 Transmission of MasterInformationBlockSidelink message 5.8.9.5 Actions related to PC5-RRC connection release requested by upper layers 5.8.9.5a Actions related to end-to-end PC5-RRC connection release performed by L2 U2U Remote UE 5.8.9.6 Sidelink UE assistance information 5.8.9.6.1 General 5.8.9.6.2 Initiation 5.8.9.6.3 Actions related to reception of UEAssistanceInformationSidelink message 5.8.9.7 PC5 Relay RLC channel management for L2 U2N or U2U relay 5.8.9.7.1 PC5 Relay RLC channel release 5.8.9.7.2 PC5 Relay RLC channel addition/modification
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5.8.9.2 Sidelink UE capability transfer p. 415

5.8.9.2.1 General p. 415

This clause describes how the UE compiles and transfers its sidelink UE capability information for unicast to the initiating UE.

Reproduction of 3GPP TS 38.331, Fig. 5.8.9.2.1-1: Sidelink UE capability transfer

Figure 5.8.9.2.1-1: Sidelink UE capability transfer

5.8.9.2.2 Initiation p. 415

The UE may initiate the sidelink UE capability transfer procedure upon indication from upper layer when it needs (additional) UE radio access capability information.

5.8.9.2.3 Actions related to transmission of the UECapabilityEnquirySidelink by the UE p. 415

The initiating UE shall set the contents of UECapabilityEnquirySidelink message as follows:

1 >

include in UE radio access capabilities for sidelink within ue-CapabilityInformationSidelink, if needed;

1 >

set frequencyBandListFilterSidelink to include frequency bands for which the peer UE is requested to provide supported bands and band combinations;

1 >

submit the UECapabilityEnquirySidelink message to lower layers for transmission.

5.8.9.2.4 Actions related to reception of the UECapabilityEnquirySidelink by the UE p. 416

The peer UE shall set the contents of UECapabilityInformationSidelink message as follows:

1 >

include UE radio access capabilities for sidelink within ue-CapabilityInformationSidelink;

1 >

compile a list of "candidate band combinations" only consisting of bands included in frequencyBandListFilterSidelink, and prioritized in the order of frequencyBandListFilterSidelink (i.e. first include band combinations containing the first-listed band, then include remaining band combinations containing the second-listed band, and so on).

1 >

include into supportedBandCombinationListSidelinkNR as many band combinations as possible from the list of "candidate band combinations", starting from the first entry;

1 >

include the received frequencyBandListFilterSidelink in the field appliedFreqBandListFilter of the requested UE capability;

1 >

submit the UECapabilityInformationSidelink message to lower layers for transmission.

5.8.9.3 Sidelink radio link failure related actions p. 416

The UE shall:

1 >

upon indication from sidelink RLC entity that the maximum number of retransmissions for a specific destination has been reached; or

1 >

upon T400 expiry for a specific destination; or

1 >

upon indication from MAC entity that the maximum number of consecutive HARQ DTX for a specific destination has been reached; or

1 >

upon integrity check failure indication from sidelink PDCP entity concerning SL-SRB2 or SL-SRB3 for a specific destination; or

1 >

upon indication of consistent sidelink LBT failures for all RB sets for a specific destination from MAC entity; or

1 >

upon reception of NotificationMessageSidelink indicating PC5 RLF from the L2 U2U Relay UE for a specific destination based on the received sl-DestinationIdentity:

2 >

consider sidelink radio link failure to be detected for this destination;

2 >

release the DRBs of this destination, according to clause 5.8.9.1a.1;

2 >

release the SRBs of this destination, according to clause 5.8.9.1a.3;

2 >

release the PC5 Relay RLC channels of this destination if configured, in according to clause 5.8.9.7.1;

2 >

discard the NR sidelink communication related configuration of this destination;

2 >

reset the sidelink specific MAC of this destination, except for L2 U2U Relay operation;

2 >

consider the PC5-RRC connection is released for the destination;

2 >

indicate the release of the PC5-RRC connection to the upper layers for this destination (i.e. PC5 is unavailable);

2 >

if UE is in RRC_CONNECTED:

3 >

if the UE is acting as L2 U2N Remote UE for the destination:

4 >

initiate the RRC connection re-establishment procedure as specified in clause 5.3.7.

3 >

else:

4 >

perform the sidelink UE information for NR sidelink communication procedure, as specified in clause 5.8.3.3;

5.8.9.3a End-to-end PC5 connection failure related actions performed by L2 U2U Remote UE p. 417

5.8.9.3b End-to-end PC5 connection failure/release related actions performed by L2 U2U Relay UE p. 418

5.8.9.4 Sidelink common control information p. 418

5.8.9.4.1 General p. 418

The sidelink common control information is carried by MasterInformationBlockSidelink. The sidelink common control information may change at any transmission, i.e. neither a modification period nor a change notification mechanism is used. This procedure also applies to NR sidelink discovery.

A UE configured to receive or transmit NR sidelink communication/discovery/positioning shall:

1 >

if the UE has a selected SyncRef UE, as specified in clause 5.8.6:

2 >

ensure having a valid version of the MasterInformationBlockSidelink message of that SyncRef UE;

5.8.9.4.2 Actions related to reception of MasterInformationBlockSidelink message p. 418

Upon receiving MasterInformationBlockSidelink, the UE shall:

1 >

apply the values included in the received MasterInformationBlockSidelink message.

5.8.9.4.3 Transmission of MasterInformationBlockSidelink message p. 418

The UE shall set the contents of the MasterInformationBlockSidelink message as follows:

1 >

if in coverage on the frequency used for the NR sidelink communication/positioning as defined in TS 38.304.

2 >

set inCoverage to true;

2 >

if tdd-UL-DL-ConfigurationCommon is included in the received SIB1:

3 >

set sl-TDD-Config to the value representing the same meaning as that is included in tdd-UL-DL-ConfigurationCommon, as described in clause 16.1 of TS 38.213;

2 >

else:

3 >

set sl-TDD-Config to the value as specified in clause 16.1 of TS 38.213;

2 >

if syncInfoReserved is included in an entry of configured sl-SyncConfigList corresponding to the concerned frequency from the received SIB12:

3 >

set reservedBits to the value of syncInfoReserved in the received SIB12;

2 >

else:

3 >

set all bits in reservedBits to 0;

1 >

else if out of coverage on the frequency used for NR sidelink communication/positioning as defined in TS 38.304; and the concerned frequency is included in sl-FreqInfoToAddModList/ sl-FreqInfoToAddModListExt in RRCReconfiguration or in sl-FreqInfoList/ sl-FreqInfoListSizeExt within SIB12:

2 >

set inCoverage to true;

2 >

set reservedBits to the value of the corresponding field included in the preconfigured sidelink parameters (i.e. sl-PreconfigGeneral in SidelinkPreconfigNR defined in clause 9.3);

2 >

set sl-TDD-Config to the value representing the same meaning as that is included in the corresponding field included in the preconfigured sidelink parameters (i.e. sl-PreconfigGeneral in SL-PreconfigurationNR defined in clause 9.3) as described in clause 16.1 of TS 38.213;

1 >

else if out of coverage on the frequency used for NR sidelink communication/positioning as defined in TS 38.304; and the UE selects GNSS as the synchronization reference and sl-SSB-TimeAllocation3 is not configured for the frequency used in SidelinkPreconfigNR:

2 >

set inCoverage to true;

2 >

set reservedBits to the value of the corresponding field included in the preconfigured sidelink parameters (i.e. sl-PreconfigGeneral in SidelinkPreconfigNR defined in clause 9.3);

2 >

1 >

else if the UE has a selected SyncRef UE (as defined in clause 5.8.6):

2 >

set inCoverage to false;

2 >

set sl-TDD-Config and reservedBits to the value of the corresponding field included in the received MasterInformationBlockSidelink;

1 >

else:

2 >

set inCoverage to false;

2 >

set reservedBits to the value of the corresponding field included in the preconfigured sidelink parameters (i.e. sl-PreconfigGeneral in SidelinkPreconfigNR defined in clause 9.3);

2 >

1 >

set directFrameNumber and slotIndex according to the slot used to transmit the SLSS, as specified in clause 5.8.5.3;

1 >

submit the MasterInformationBlockSidelink to lower layers for transmission upon which the procedure ends;

5.8.9.5 Actions related to PC5-RRC connection release requested by upper layers p. 420

The UE initiates the procedure when upper layers request the release of the PC5-RRC connection as specified in TS 24.587 or TS 24.554. The UE shall not initiate the procedure for power saving purposes.

The UE shall:

1 >

if the PC5-RRC connection release for the specific destination is requested by upper layers:

2 >

discard the NR sidelink communication related configuration of this destination;

2 >

release the DRBs of this destination if configured, in according to clause 5.8.9.1a.1;

2 >

release the SRBs of this destination, in according to clause 5.8.9.1a.3;

2 >

release the PC5 Relay RLC channels if configured, in according to clause 5.8.9.7.1;

2 >

reset the sidelink specific MAC of this destination.

2 >

consider the PC5-RRC connection is released for the destination;

5.8.9.5a Actions related to end-to-end PC5-RRC connection release performed by L2 U2U Remote UE p. 420

5.8.9.6 Sidelink UE assistance information p. 421

5.8.9.6.1 General p. 421

Reproduction of 3GPP TS 38.331, Fig. 5.8.9.6.1-1: Sidelink UE assistance information

Figure 5.8.9.6.1-1: Sidelink UE assistance information

The purpose of this procedure is for a UE to inform its peer UE of the sidelink DRX assistance information used to determine the sidelink DRX configuration for unicast communication.

For sidelink unicast, a UE may include its desired sidelink DRX configurations in the UEAssistanceInformationSidelink as the sidelink DRX assistance information which is transmitted to its peer UE.

5.8.9.6.2 Initiation p. 421

For sidelink unicast, if both a RX UE and its peer TX UE for a direction of sidelink communication are capable of sidelink DRX, the RX UE that is interested in sending the sidelink DRX assistance information may send the UEAssistanceInformationSidelink as the sidelink DRX assistance information to its peer UE when the sidelink DRX assistance information has not been sent previously or when the previously transmitted sidelink DRX assistance information has changed.

5.8.9.6.3 Actions related to reception of UEAssistanceInformationSidelink message p. 421

For sidelink unicast, when a UE is in RRC_CONNECTED and is performing sidelink operation with resource allocation mode 1, it may report the sidelink DRX assistance information received within the UEAssistanceInformationSidelink from its peer UE to the network as specified in clause 5.8.3. For sidelink unicast, when a UE is in RRC_CONNECTED and is performing sidelink operation with resource allocation mode 2 or is in RRC_IDLE or RRC_INACTIVE or out of coverage, regardless of whether the UE has obtained the sidelink DRX assistance information from the UEAssistanceInformationSidelink transmitted from its peer UE or not, it may determine the sidelink DRX configuration SL-DRX-ConfigUC for its peer UE.

5.8.9.7 PC5 Relay RLC channel management for L2 U2N or U2U relay p. 421

5.8.9.7.1 PC5 Relay RLC channel release p. 421

The UE shall:

1 >

if the PC5 Relay RLC channel release was triggered after the reception of the RRCReconfigurationSidelink message; or

1 >

after receiving the RRCReconfigurationCompleteSidelink message, if the PC5 Relay RLC channel release was triggered due to the configuration received within the sl-ConfigDedicatedNR; or

1 >

for unicast in L2 U2U relay operation, if there is no end-to-end sidelink DRB(s) associated with this RLC channel:

2 >

for each SL-RLC-ChannelID in sl-RLC-ChannelToReleaseList received in sl-ConfigDedicatedNR within RRCReconfiguration, or for each SL-RLC-ChannelID included in the received sl-RLC-ChannelToReleaseListPC5 that is part of the current UE sidelink configuration, or for the RLC channel to be released:

3 >

release the RLC entity and the corresponding logical channel associated with the SL-RLC-ChannelID;

1 >

if the PC5 Relay RLC channel release was triggered for a specific destination by upper layers as specified in clause 5.8.9.5, or for a specific destination corresponding to the received sl-DestinationIdentityRemoteUE by upper layers as specified in clause 5.8.9.10.4, or due to sidelink RLF as specified in clause 5.8.9.3:

2 >

release the RLC entity and the corresponding logical channel associated with the SL-RLC-ChannelID of the specific destination;

5.8.9.7.2 PC5 Relay RLC channel addition/modification p. 422

Upon PC5-RRC connection establishment between the L2 U2N Relay UE and L2 U2N Remote UE, the L2 U2N Relay UE shall:

1 >

establish a SRAP entity as specified in TS 38.351, if no SRAP entity has been established;

1 >

apply RLC specified configuration of SL-RLC0 as specified in clause 9.1.1.4:

1 >

apply RLC default configuration of SL-RLC1 as defined in clause 9.2.4 if the L2 U2N Relay UE is in RRC_IDLE/INACTIVE state;

Upon PC5-RRC connection establishment between the L2 U2U Remote UE and L2 U2U Relay UE, and PC5-RRC connection establishment between the L2 U2U Relay UE and peer L2 U2U Remote UE, the L2 U2U Remote UE or L2 U2U Relay UE shall:

1 >

establish a SRAP entity as specified in TS 38.351, if no SRAP entity has been established;

1 >

apply RLC specified configuration of SL-U2U-RLC as specified in clause 9.1.1.4;

The UE shall:

1 >

if the PC5 Relay RLC channel addition/modification was triggered due to the reception of the RRCReconfigurationSidelink message; or

1 >

after receiving the RRCReconfigurationCompleteSidelink message, if the PC5 Relay RLC channel addition/modification was triggered due to the configuration received within the sl-ConfigDedicatedNR; or

1 >

after receiving the RRCReconfigurationCompleteSidelink message, if the PC5 Relay RLC channel addition/modification was triggered for an end-to-end sidelink DRB based on the configuration in SIB12 or SidelinkPreconfigNR:

2 >

if the current configuration contains a PC5 Relay RLC channel with the received sl-RLC-ChannelID or sl-RLC-ChannelID-PC5; or

2 >

if the configuration in SIB12 or SidelinkPreconfigNR has updated, based on which the PC5 Relay RLC channel is derived:

3 >

reconfigure the sidelink RLC entity in accordance with the received sl-RLC-Config or sl-RLC-ConfigPC5;

3 >

reconfigure the sidelink MAC entity with a logical channel in accordance with the received sl-MAC-LogicalChannelConfig or sl-MAC-LogicalChannelConfigPC5;

2 >

else (a PC5 Relay RLC channel with the received sl-RLC-ChannelID or sl-RLC-ChannelID-PC5 was not configured before):

3 >

establish a sidelink RLC entity in accordance with the received sl-RLC-Config (in sl-ConfigDedicatedNR, or SIB12, or SidelinkPreconfigNR) or sl-RLC-ConfigPC5;

3 >

configure the sidelink MAC entity with a logical channel in accordance with the received sl-MAC-LogicalChannelConfig or sl-MAC-LogicalChannelConfigPC5.