Content for TS 38.331 Word version: 17.4.0

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… 5.3.6… 5.3.8… 5.3.13… 5.3.14… 5.4… 5.5… 5.5.3… 5.5.4… 5.5.5… 5.5a… 5.7… 5.7.4… 5.7.8… 5.8… 5.8.9… 5.8.10… 5.8.11… 5.9… 6… 6.2.2… 6-2-2-25… 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… 6.3.3… 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 Sidelink RRC procedure 5.8.9.1 Sidelink RRC reconfiguration 5.8.9.1a Sidelink radio bearer management 5.8.9.2 Sidelink UE capability transfer 5.8.9.3 Sidelink radio link failure related actions 5.8.9.4 Sidelink common control information 5.8.9.5 Actions related to PC5-RRC connection release requested by upper layers 5.8.9.6 Sidelink UE assistance information 5.8.9.7 PC5 Relay RLC channel management for L2 U2N relay 5.8.9.8 Remote UE information 5.8.9.9 Uu message transfer in sidelink 5.8.9.10 Notification Message
...

5.8.9 Sidelink RRC procedure p. 303

5.8.9.1 Sidelink RRC reconfiguration p. 303

5.8.9.1.1 General p. 303

Reproduction of 3GPP TS 38.331, Fig. 5.8.9.1.1-1: Sidelink RRC reconfiguration, successful

Figure 5.8.9.1.1-1: Sidelink RRC reconfiguration, successful

Reproduction of 3GPP TS 38.331, Fig. 5.8.9.1.1-2: Sidelink RRC reconfiguration, failure

Figure 5.8.9.1.1-2: Sidelink RRC reconfiguration, failure

The purpose of this procedure is to modify a PC5-RRC connection, e.g. to establish/modify/release sidelink DRBs or PC5 Relay RLC channels, to (re-)configure NR sidelink measurement and reporting, to (re-)configure sidelink CSI reference signal resources, to (re)configure CSI reporting latency bound, to (re)configure sidelink DRX, and to (re-)configure the latency bound of SL Inter-UE coordination report.

The UE may initiate the sidelink RRC reconfiguration procedure and perform the operation in clause 5.8.9.1.2 on the corresponding PC5-RRC connection in following cases:

the release of sidelink DRBs associated with the peer UE, as specified in clause 5.8.9.1a.1;
the establishment of sidelink DRBs associated with the peer UE, as specified in clause 5.8.9.1a.2;
the modification for the parameters included in SLRB-Config of sidelink DRBs associated with the peer UE, as specified in clause 5.8.9.1a.2;
the release of PC5 Relay RLC channels for L2 U2N Relay UE and Remote UE, as specified in clause 5.8.9.7.1;
the establishment of PC5 Relay RLC channels for L2 U2N Relay UE and Remote UE, as specified in clause 5.8.9.7.2;
the modification for the parameters included in SL-RLC-ChannelConfigPC5 of PC5 Relay RLC channels for L2 U2N Relay UE and Remote UE, as specified in clause 5.8.9.7.2;
the (re-)configuration of the peer UE to perform NR sidelink measurement and report.
the (re-)configuration of the sidelink CSI reference signal resources and CSI reporting latency bound;
the (re-)configuration of the peer UE to perform sidelink DRX;
the (re-)configuration of the latency bound of SL Inter-UE coordination report.

In RRC_CONNECTED, the UE applies the NR sidelink communications parameters provided in RRCReconfiguration (if any). In RRC_IDLE or RRC_INACTIVE, the UE applies the NR sidelink communications parameters provided in system information (if any). For other cases, UEs apply the NR sidelink communications parameters provided in SidelinkPreconfigNR (if any). When UE performs state transition between above three cases, the UE applies the NR sidelink communications parameters provided in the new state, after acquisition of the new configurations. Before acquisition of the new configurations, UE continues applying the NR sidelink communications parameters provided in the old state.

5.8.9.1.2 Actions related to transmission of RRCReconfigurationSidelink message p. 304

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

1 >

for each sidelink DRB that is to be released, according to clause 5.8.9.1a.1.1, due to configuration by sl-ConfigDedicatedNR, SIB12, SidelinkPreconfigNR or by upper layers:

2 >

set the entry included in the slrb-ConfigToReleaseList corresponding to the sidelink DRB;

1 >

for each sidelink DRB that is to be established or modified, according to clause 5.8.9.1a.2.1, due to receiving sl-ConfigDedicatedNR, SIB12 or SidelinkPreconfigNR:

2 >

if a sidelink DRB is to be established:

3 >

assign a new logical channel identity for the logical channel to be associated with the sidelink DRB and set sl-MAC-LogicalChannelConfigPC5 in the SLRB-Config to include the new logical channel identity;

2 >

set the SLRB-Config included in the slrb-ConfigToAddModList, according to the received sl-RadioBearerConfig and sl-RLC-BearerConfig corresponding to the sidelink DRB;

1 >

set the sl-MeasConfig as follows:

2 >

If the frequency used for NR sidelink communication is included in sl-FreqInfoToAddModList in sl-ConfigDedicatedNR within RRCReconfiguration message or included in sl-ConfigCommonNR within SIB12:

3 >

if UE is in RRC_CONNECTED:

4 >

set the sl-MeasConfig according to stored NR sidelink measurement configuration information for this destination;

3 >

if UE is in RRC_IDLE or RRC_INACTIVE:

4 >

set the sl-MeasConfig according to stored NR sidelink measurement configuration received from SIB12;

2 >

else:

3 >

set the sl-MeasConfig according to the sl-MeasPreconfig in SidelinkPreconfigNR;

1 >

set the sl-LatencyBoundIUC-Report;

1 >

start timer T400 for the destination;

1 >

set the sl-CSI-RS-Config;

1 >

set the sl-LatencyBoundCSI-Report;

1 >

set the sl-ResetConfig;

1 >

set the sl-DRX-ConfigUC-PC5 as follows:

2 >

If the frequency used for NR sidelink communication is included in sl-FreqInfoToAddModList in sl-ConfigDedicatedNR within RRCReconfiguration message or included in sl-ConfigCommonNR within SIB12:

3 >

if UE is in RRC_CONNECTED and if sl-ScheduledConfig is included in sl-ConfigDedicatedNR within RRCReconfiguration:

4 >

set the sl-DRX-ConfigUC-PC5 according to stored NR sidelink DRX configuration information for this destination.

1 >

for each PC5 Relay RLC channel that is to be released due to configuration by sl-ConfigDedicatedNR:

2 >

set the SL-RLC-ChannelID corresponding to the PC5 Relay RLC channel in the sl-RLC-ChannelToReleaseListPC5;

1 >

for each PC5 Relay RLC channel that is to be established or modified due to receiving sl-ConfigDedicatedNR:

2 >

if a PC5 Relay RLC channel is to be established:

3 >

assign a new logical channel identity for the logical channel to be associated with the PC5 Relay RLC channel and set sl-MAC-LogicalChannelConfigPC5 in the SL-RLC-ChannelConfigPC5 to include the new logical channel identity;

2 >

set the SL-RLC-ChannelConfigPC5 included in the sl-RLC-ChannelToAddModListPC5 according to the received SL-RLC-ChannelConfig corresponding to the PC5 Relay RLC channel, including setting sl-RLC-ChannelID-PC5 to the same value of sl-RLC-ChannelID received in SL-RLC-ChannelConfig;

The UE shall submit the RRCReconfigurationSidelink message to lower layers for transmission.

5.8.9.1.3 Reception of an RRCReconfigurationSidelink by the UE p. 305

The UE shall perform the following actions upon reception of the RRCReconfigurationSidelink:

1 >

if the RRCReconfigurationSidelink includes the sl-ResetConfig:

2 >

perform the sidelink reset configuration procedure as specified in clause 5.8.9.1.10;

1 >

if the RRCReconfigurationSidelink includes the slrb-ConfigToReleaseList:

2 >

for each entry value included in the slrb-ConfigToReleaseList that is part of the current UE sidelink configuration;

3 >

perform the sidelink DRB release procedure, according to clause 5.8.9.1a.1;

1 >

if the RRCReconfigurationSidelink includes the slrb-ConfigToAddModList:

2 >

for each slrb-PC5-ConfigIndex value included in the slrb-ConfigToAddModList that is not part of the current UE sidelink configuration:

3 >

if sl-MappedQoS-FlowsToAddList is included:

4 >

apply the SL-PQFI included in sl-MappedQoS-FlowsToAddList;

3 >

perform the sidelink DRB addition procedure, according to clause 5.8.9.1a.2;

2 >

for each slrb-PC5-ConfigIndex value included in the slrb-ConfigToAddModList that is part of the current UE sidelink configuration:

3 >

if sl-MappedQoS-FlowsToAddList is included:

4 >

add the SL-PQFI included in sl-MappedQoS-FlowsToAddList to the corresponding sidelink DRB;

3 >

if sl-MappedQoS-FlowsToReleaseList is included:

4 >

remove the SL-PQFI included in sl-MappedQoS-FlowsToReleaseList from the corresponding sidelink DRB;

3 >

if the sidelink DRB release conditions as described in clause 5.8.9.1a.1.1 are met:

4 >

perform the sidelink DRB release procedure according to clause 5.8.9.1a.1.2;

3 >

else if the sidelink DRB modification conditions as described in clause 5.8.9.1a.2.1 are met:

4 >

perform the sidelink DRB modification procedure according to clause 5.8.9.1a.2.2;

1 >

if the RRCReconfigurationSidelink message includes the sl-MeasConfig:

2 >

perform the sidelink measurement configuration procedure as specified in clause 5.8.10;

1 >

if the RRCReconfigurationSidelink message includes the sl-CSI-RS-Config:

2 >

apply the sidelink CSI-RS configuration;

1 >

if the RRCReconfigurationSidelink message includes the sl-LatencyBoundCSI-Report:

2 >

apply the configured sidelink CSI report latency bound;

1 >

if the RRCReconfigurationSidelink includes the sl-RLC-ChannelToReleaseListPC5:

2 >

for each SL-RLC-ChannelID value included in the sl-RLC-ChannelToReleaseListPC5 that is part of the current UE sidelink configuration;

3 >

perform the PC5 Relay RLC channel release procedure, according to clause 5.8.9.7.1;

1 >

if the RRCReconfigurationSidelink includes the sl-RLC-ChannelToAddModListPC5:

2 >

for each sl-RLC-ChannelID-PC5 value included in the sl-RLC-ChannelToAddModListPC5 that is not part of the current UE sidelink configuration:

3 >

perform the PC5 Relay RLC channel addition procedure, according to clause 5.8.9.7.2;

2 >

for each sl-RLC-ChannelID-PC5 value included in the sl-RLC-ChannelToAddModListPC5 that is part of the current UE sidelink configuration:

3 >

perform the PC5 Relay RLC channel modification procedure according to clause 5.8.9.7.2;

1 >

if the RRCReconfigurationSidelink message includes the sl-DRX-ConfigUC-PC5, and

1 >

if the UE accepts the sl-DRX-ConfigUC-PC5:

2 >

configure lower layers to perform sidelink DRX operation according to sl-DRX-ConfigUC-PC5 for the associated destination as defined in TS 38.321;

1 >

if the RRCReconfigurationSidelink message includes the sl-LatencyBoundIUC-Report:

2 >

apply the configured sidelink IUC report latency bound;

1 >

if the UE is unable to comply with (part of) the configuration included in the RRCReconfigurationSidelink (i.e. sidelink RRC reconfiguration failure):

2 >

continue using the configuration used prior to the reception of the RRCReconfigurationSidelink message;

2 >

set the content of the RRCReconfigurationFailureSidelink message;

3 >

submit the RRCReconfigurationFailureSidelink message to lower layers for transmission;

1 >

else:

2 >

set the content of the RRCReconfigurationCompleteSidelink message;

3 >

if the UE rejects the sidelink DRX configuration sl-DRX-ConfigUC-PC5 received from the peer UE:

4 >

include the sl-DRX-ConfigReject in the RRCReconfigurationCompleteSidelink message;

4 >

consider no sidelink DRX to be applied for the corresponding sidelink unicast communication;

3 >

submit the RRCReconfigurationCompleteSidelink message to lower layers for transmission;

5.8.9.1.4 Void

5.8.9.1.5 Void

5.8.9.1.6 Void

5.8.9.1.7 Void

5.8.9.1.8 Reception of an RRCReconfigurationFailureSidelink by the UE p. 307

The UE shall perform the following actions upon reception of the RRCReconfigurationFailureSidelink:

1 >

stop timer T400 for the destination, if running;

1 >

continue using the configuration used prior to corresponding RRCReconfigurationSidelink message;

1 >

if UE is in RRC_CONNECTED:

2 >

perform the sidelink UE information for NR sidelink communication procedure, as specified in clause 5.8.3.3 or clause 5.10.15 in TS 36.331;

5.8.9.1.9 Reception of an RRCReconfigurationCompleteSidelink by the UE p. 307

The UE shall perform the following actions upon reception of the RRCReconfigurationCompleteSidelink:

1 >

stop timer T400 for the destination, if running;

1 >

consider the configurations in the corresponding RRCReconfigurationSidelink message to be applied.

2 >

if the RRCReconfigurationCompleteSidelink message includes the sl-DRX-ConfigReject:

3 >

consider no sidelink DRX to be applied for the corresponding sidelink unicast communication.

5.8.9.1.10 Sidelink reset configuration |R17| p. 307

The UE shall:

1 >

release/clear current sidelink radio configuration of this destination received in the RRCReconfigurationSidelink;

1 >

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

1 >

reset the sidelink specific MAC of this destination.

5.8.9.1a Sidelink radio bearer management p. 307

5.8.9.1a.1 Sidelink DRB release p. 307

5.8.9.1a.1.1 Sidelink DRB release conditions p. 307

For NR sidelink communication, a sidelink DRB release is initiated in the following cases:

1 >

for groupcast, broadcast and unicast, if slrb-Uu-ConfigIndex (if any) of the sidelink DRB is included in sl-RadioBearerToReleaseList in sl-ConfigDedicatedNR; or

1 >

for groupcast and broadcast, if no sidelink QoS flow with data indicated by upper layers is mapped to the sidelink DRB for transmission, which is (re)configured by receiving SIB12 or SidelinkPreconfigNR; or

1 >

for groupcast, broadcast and unicast, if SL-RLC-BearerConfigIndex (if any) of the sidelink DRB is included in sl-RLC-BearerToReleaseList in sl-ConfigDedicatedNR; or

1 >

for unicast, if no sidelink QoS flow with data indicated by upper layers is mapped to the sidelink DRB for transmission, which is (re)configured by receiving SIB12 or SidelinkPreconfigNR, and if no sidelink QoS flow mapped to the sidelink DRB, which is (re)configured by receiving RRCReconfigurationSidelink, has data; or

1 >

for unicast, if SLRB-PC5-ConfigIndex (if any) of the sidelink DRB is included in slrb-ConfigToReleaseList in RRCReconfigurationSidelink or if sl-ResetConfig is included in RRCReconfigurationSidelink; or

1 >

for unicast, when the corresponding PC5-RRC connection is released due to sidelink RLF being detected, according to clause 5.8.9.3; or

1 >

for unicast, when the corresponding PC5-RRC connection is released due to upper layer request according to clause 5.8.9.5.

5.8.9.1a.1.2 Sidelink DRB release operations p. 307

For each sidelink DRB, whose sidelink DRB release conditions are met as in clause 5.8.9.1a.1.1, the UE capable of NR sidelink communication that is configured by upper layers to perform NR sidelink communication shall:

1 >

for groupcast and broadcast; or

1 >

for unicast, if the sidelink DRB release was triggered after the reception of the RRCReconfigurationSidelink message; or

1 >

for unicast, after receiving the RRCReconfigurationCompleteSidelink message, if the sidelink DRB release was triggered due to the configuration received within the sl-ConfigDedicatedNR, SIB12, SidelinkPreconfigNR or indicated by upper layers:

2 >

release the PDCP entity for NR sidelink communication associated with the sidelink DRB;

2 >

if SDAP entity for NR sidelink communication associated with this sidelink DRB is configured:

3 >

indicate the release of the sidelink DRB to the SDAP entity associated with this sidelink DRB (clause 5.3.3 of TS 37.324);

2 >

release SDAP entities for NR sidelink communication, if any, that have no associated sidelink DRB as specified in clause 5.1.2 of TS 37.324;

1 >

for groupcast and broadcast; or

1 >

for unicast, after receiving the RRCReconfigurationCompleteSidelink message, if the sidelink DRB release was triggered due to the configuration received within the sl-ConfigDedicatedNR:

2 >

for each sl-RLC-BearerConfigIndex included in the received sl-RLC-BearerToReleaseList that is part of the current UE sidelink configuration:

3 >

release the RLC entity and the corresponding logical channel for NR sidelink communication, associated with the sl-RLC-BearerConfigIndex.

1 >

for unicast, if the sidelink DRB release was triggered due to the reception of the RRCReconfigurationSidelink message; or

1 >

for unicast, after receiving the RRCReconfigurationCompleteSidelink message, if the sidelink DRB release was triggered due to the configuration received within the SIB12, SidelinkPreconfigNR or indicated by upper layers:

2 >

release the RLC entity and the corresponding logical channel for NR sidelink communication associated with the sidelink DRB;

2 >

perform the sidelink UE information procedure in clause 5.8.3 for unicast if needed.

1 >

if the sidelink radio link failure is detected for a specific destination:

2 >

release the PDCP entity, RLC entity and the logical channel of the sidelink DRB for the specific destination.

5.8.9.1a.2 Sidelink DRB addition/modification p. 309

5.8.9.1a.2.1 Sidelink DRB addition/modification conditions p. 209

For NR sidelink communication, a sidelink DRB addition is initiated only in the following cases:

1 >

if any sidelink QoS flow is (re)configured by sl-ConfigDedicatedNR, SIB12, SidelinkPreconfigNR and is to be mapped to one sidelink DRB, which is not established; or

1 >

if any sidelink QoS flow is (re)configured by RRCReconfigurationSidelink and is to be mapped to a sidelink DRB, which is not established;

For NR sidelink communication, a sidelink DRB modification is initiated only in the following cases:

1 >

if any of the sidelink DRB related parameters is changed by sl-ConfigDedicatedNR, SIB12, SidelinkPreconfigNR or RRCReconfigurationSidelink for one sidelink DRB, which is established;

5.8.9.1a.2.2 Sidelink DRB addition/modification operations p. 209

For the sidelink DRB, whose sidelink DRB addition conditions are met as in clause 5.8.9.1a.2.1, the UE capable of NR sidelink communication that is configured by upper layers to perform NR sidelink communication shall:

1 >

for groupcast and broadcast; or

1 >

for unicast, if the sidelink DRB addition was triggered due to the reception of the RRCReconfigurationSidelink message; or

1 >

for unicast, after receiving the RRCReconfigurationCompleteSidelink message, if the sidelink DRB addition was triggered due to the configuration received within the sl-ConfigDedicatedNR, SIB12, SidelinkPreconfigNR or indicated by upper layers:

2 >

if an SDAP entity for NR sidelink communication associated with the destination and the cast type of the sidelink DRB does not exist:

3 >

establish an SDAP entity for NR sidelink communication as specified in clause 5.1.1 of TS 37.324;

2 >

(re)configure the SDAP entity in accordance with the sl-SDAP-ConfigPC5 received in the RRCReconfigurationSidelink or sl-SDAP-Config received in sl-ConfigDedicatedNR, SIB12, SidelinkPreconfigNR, associated with the sidelink DRB;

2 >

establish a PDCP entity for NR sidelink communication and configure it in accordance with the sl-PDCP-ConfigPC5 received in the RRCReconfigurationSidelink or sl-PDCP-Config received in sl-ConfigDedicatedNR, SIB12, SidelinkPreconfigNR, associated with the sidelink DRB;

2 >

establish a RLC entity for NR sidelink communication and configure it in accordance with the sl-RLC-ConfigPC5 received in the RRCReconfigurationSidelink or sl-RLC-Config received in sl-ConfigDedicatedNR, SIB12, SidelinkPreconfigNR, associated with sidelink DRB;

2 >

if this procedure was due to the reception of a RRCReconfigurationSidelink message:

3 >

configure the MAC entity with a logical channel in accordance with the sl-MAC-LogicalChannelConfigPC5 received in the RRCReconfigurationSidelink associated with the sidelink DRB, and perform the sidelink UE information procedure in clause 5.8.3 for unicast if need;

2 >

else if this procedure was due to the reception of a RRCReconfigurationCompleteSidelink message:

3 >

configure the MAC entity with a logical channel associated with the sidelink DRB, in accordance with the sl-MAC-LogicalChannelConfig received in the sl-ConfigDedicatedNR, SIB12, SidelinkPreconfigNR;

2 >

else (i.e. for groupcast/broadcast):

3 >

configure the MAC entity with a logical channel associated with the sidelink DRB, in accordance with the sl-MAC-LogicalChannelConfig received in the sl-ConfigDedicatedNR, SIB12, SidelinkPreconfigNR and assign a new LCID to this logical channel.

For the sidelink DRB, whose sidelink DRB modification conditions are met as in clause 5.8.9.1a.2.1, the UE capable of NR sidelink communication that is configured by upper layers to perform NR sidelink communication shall:

1 >

for groupcast and broadcast; or

1 >

for unicast, if the sidelink DRB modification was triggered due to the reception of the RRCReconfigurationSidelink message; or

1 >

for unicast, after receiving the RRCReconfigurationCompleteSidelink message, if the sidelink DRB modification was triggered due to the configuration received within the sl-ConfigDedicatedNR, SIB12 or SidelinkPreconfigNR:

2 >

reconfigure the SDAP entity of the sidelink DRB, in accordance with the sl-SDAP-ConfigPC5 received in the RRCReconfigurationSidelink or sl-SDAP-Config received in sl-ConfigDedicatedNR, SIB12, SidelinkPreconfigNR, if included;

2 >

reconfigure the PDCP entity of the sidelink DRB, in accordance with the sl-PDCP-ConfigPC5 received in the RRCReconfigurationSidelink or sl-PDCP-Config received in sl-ConfigDedicatedNR, SIB12, SidelinkPreconfigNR, if included;

2 >

reconfigure the RLC entity of the sidelink DRB, in accordance with the sl-RLC-ConfigPC5 received in the RRCReconfigurationSidelink or sl-RLC-Config received in sl-ConfigDedicatedNR, SIB12, SidelinkPreconfigNR, if included;

2 >

reconfigure the logical channel of the sidelink DRB, in accordance with the sl-MAC-LogicalChannelConfigPC5 received in the RRCReconfigurationSidelink or sl-MAC-LogicalChannelConfig received in sl-ConfigDedicatedNR, SIB12, SidelinkPreconfigNR, if included.

5.8.9.1a.3 Sidelink SRB release p. 310

The UE shall:

1 >

if a PC5-RRC connection release for a specific destination is requested by upper layers or AS layer; or

1 >

if the sidelink radio link failure is detected for a specific destination:

2 >

release the PDCP entity, RLC entity and the logical channel of the sidelink SRB for PC5-RRC message of the specific destination;

2 >

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

1 >

if PC5-S transmission for a specific destination is terminated in upper layers:

2 >

release the PDCP entity, RLC entity and the logical channel of the sidelink SRB(s) for PC5-S message of the specific destination;

1 >

if discovery transmission for a specific destination is terminated in upper layers:

2 >

release the PDCP entity, RLC entity and the logical channel of the sidelink SRB4 for discovery message of the specific destination;

5.8.9.1a.4 Sidelink SRB addition p. 310

The UE shall:

1 >

if transmission of PC5-S message for a specific destination is requested by upper layers for sidelink SRB:

2 >

establish PDCP entity, RLC entity and the logical channel of a sidelink SRB for PC5-S message, as specified in clause 9.1.1.4;

1 >

if transmission of discovery message for a specific destination is requested by upper layers for sidelink SRB:

2 >

establish PDCP entity, RLC entity and the logical channel of a sidelink SRB4 for discovery message, as specified in clause 9.1.1.4;

1 >

if a PC5-RRC connection establishment for a specific destination is indicated by upper layers:

2 >

establish PDCP entity, RLC entity and the logical channel of a sidelink SRB for PC5-RRC message of the specific destination, as specified in clause 9.1.1.4;

2 >

consider the PC5-RRC connection is established for the destination.

5.8.9.2 Sidelink UE capability transfer p. 311

5.8.9.2.1 General p. 311

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. 311

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. 311

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. 311

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. 312

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:

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;

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;

5.8.9.4 Sidelink common control information p. 312

5.8.9.4.1 General p. 312

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 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. 313

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. 313

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 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 as defined in TS 38.304; and the concerned frequency is included in sl-FreqInfoToAddModList in RRCReconfiguration or in sl-FreqInfoList 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 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. 314

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;

5.8.9.6 Sidelink UE assistance information |R17| p. 314

5.8.9.6.1 General p. 314

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. 314

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. 315

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 relay |R17| p. 315

5.8.9.7.1 PC5 Relay RLC channel release p. 315

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:

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:

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:

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. 315

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;

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:

2 >

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

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 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.

5.8.9.8 Remote UE information |R17| p. 316

5.8.9.8.1 General p. 316

Reproduction of 3GPP TS 38.331, Fig. 5.8.9.8.1-1: Remote UE information

Figure 5.8.9.8.1-1: Remote UE information

This procedure is used by the L2 U2N Remote UE in RRC_IDLE/RRC_INACTIVE to inform about the required SIB(s) and provide Paging related information to the connected L2 U2N Relay UE.

5.8.9.8.2 Actions related to transmission of RemoteUEInformationSidelink message p. 316

When entering RRC_IDLE or RRC_INACTIVE, or upon change in any of the information in the RemoteUEInformationSidelink while in RRC_IDLE or RRC_INACTIVE, the L2 U2N Remote UE shall:

1 >

if the UE has not stored a valid version of a SIB, in accordance with clause 5.2.2.2.1, of one or several required SIB(s) in accordance with clause 5.2.2.1 and the requested SIB has not been indicated in RemoteUEInformationSidelink message to the L2 U2N Relay UE before:

2 >

include sl-RequestedSIB-List in the RemoteUEInformationSidelink to indicate the requested SIB(s);

1 >

if the UE has not sent sl-PagingInfo-RemoteUE in the RemoteUEInformationSidelink message to the L2 U2N Relay UE before, set sl-PagingInfo-RemoteUE as follows:

2 >

if the L2 U2N Remote UE is in RRC_IDLE:

3 >

include ng-5G-S-TMSI in the sl-PagingIdentityRemoteUE;

3 >

if the UE specific DRX cycle is configured by upper layer, set sl-PagingCycleRemoteUE to the value of UE specific Uu DRX cycle configured by upper layer;

2 >

else if the L2 U2N Remote UE is in RRC_INACTIVE:

3 >

include ng-5G-S-TMSI and fullI-RNTI in the sl-PagingIdentityRemoteUE;

3 >

if the UE specific DRX cycle is configured by upper layer,

4 >

set sl-PagingCycleRemoteUE to the minimum value of UE specific Uu DRX cycles (configured by upper layer and configured by RRC);

3 >

else:

4 >

set sl-PagingCycleRemoteUE to the value of UE specific DRX cycle configured by RRC;

1 >

submit the RemoteUEInformationSidelink message to lower layers for transmission;

When entering RRC_CONNECTED, if L2 U2N remote UE had sent sl-RequestedSIB-List and/or sl-PagingInfo-RemoteUE, the L2 U2N Remote UE shall:

1 >

set the sl-RequestedSIB-List to the value release if requested before;

1 >

set the sl-PagingInfo-RemoteUE to the value release if sent before;

1 >

submit the RemoteUEInformationSidelink message to lower layers for transmission;

5.8.9.8.3 Reception of RemoteUEInformationSidelink message by the L2 U2N Relay UE p. 317

The L2 U2N Relay UE shall:

1 >

if the RemoteUEInformationSidelink includes the sl-PagingInfo-RemoteUE:

2 >

if the UE is in RRC_CONNECTED on an active BWP with common search space configured including pagingSearchSpace; or

2 >

if the UE is in RRC_IDLE or RRC_INACTIVE:

3 >

if the sl-PagingInfo-RemoteUE is set to setup:

4 >

monitor the Paging message at the L2 U2N Remote UE's paging occasion calculated according to sl-PagingIdentityRemoteUE and sl-PagingCycleRemoteUE included in sl-PagingInfo-RemoteUE;

3 >

else (the sl-PagingInfo-RemoteUE is set to release):

4 >

stop monitoring the Paging message at the L2 U2N Remote UE's paging occasion;

4 >

release the received paging information in sl-PagingInfo-RemoteUE;

2 >

else (the UE is in RRC_CONNECTED on an active BWP without pagingSearchSpace configured):

3 >

if the sl-PagingInfo-RemoteUE is set to setup:

4 >

include the received sl-PagingIdentityRemoteUE in SidelinkUEInformationNR message and perform Sidelink UE information transmission in accordance with clause 5.8.3;

3 >

else (the sl-PagingInfo-RemoteUE is set to release):

4 >

initiate transmission of the SidelinkUEInformationNR message to release the sl-PagingIdentityRemoteUE in SidelinkUEInformationNR message in accordance with clause 5.8.3;

4 >

release the received paging information in sl-PagingInfo-RemoteUE;

1 >

if the RemoteUEInformationSidelink includes the sl-RequestedSIB-List:

2 >

if the sl-RequestedSIB-List is set to setup:

3 >

if the L2 U2N Relay UE has not stored a valid version of SIB(s) indicated in sl-RequestedSIB-List:

4 >

perform acquisition of the system information indicated in sl-RequestedSIB-List in accordance with clause 5.2.2;

3 >

perform the Uu message transfer procedure in accordance with clause 5.8.9.9;

2 >

if the sl-RequestedSIB-List is set to release:

3 >

release received SIB request in sl-RequestedSIB-List.

5.8.9.9 Uu message transfer in sidelink |R17| p. 318

5.8.9.9.1 General p. 318

Reproduction of 3GPP TS 38.331, Fig. 5.8.9.9.1-1: Uu message transfer in sidelink

Figure 5.8.9.9.1-1: Uu message transfer in sidelink

The purpose of this procedure is to transfer Paging message and System Information from the L2 U2N Relay UE to the L2 U2N Remote UE in RRC_IDLE/RRC_INACTIVE.

5.8.9.9.2 Actions related to transmission of UuMessageTransferSidelink message p. 318

The L2 U2N Relay UE initiates the Uu message transfer procedure when at least one of the following conditions is met:

1 >

upon receiving Paging message related to the connected L2 U2N Remote UE from network (including Paging message within RRCReconfiguration message);

1 >

upon acquisition of the SIB(s) requested by the connected L2 U2N Remote UE (as indicated in sl-RequestedSIB-List in the RemoteUEInformationSidelink) or upon receiving the updated SIB(s) from network which has been requested by the connected L2 U2N Remote UE;

1 >

upon unsolicited SIB1 forwarding to the connected L2 U2N Remote UE or upon receiving the updated SIB1 from network;

For each associated L2 U2N Remote UE, the L2 U2N Relay UE shall set the contents of UuMessageTransferSidelink message as follows:

1 >

include sl-PagingDelivery if the Paging message received from network containing the ue-Identity of the L2 U2N Remote UE;

1 >

include sl-SIB1-Delivery if any of the conditions for initiating Uu message transfer procedure related to SIB1 are met;

1 >

include sl-SystemInformationDelivery if any of the conditions for initiating Uu message transfer procedure related to System Information are met;

1 >

submit the UuMessageTransferSidelink message to lower layers for transmission.

5.8.9.9.3 Reception of the UuMessageTransferSidelink p. 318

Upon receiving the UuMessageTransferSidelink message, the L2 U2N Remote UE shall:

1 >

if sl-PagingDelivery is included:

2 >

perform the paging reception procedure as specified in clause 5.3.2.3;

1 >

if sl-SystemInformationDelivery and/or sl-SIB1-Delivery is included:

2 >

perform the actions specified in clause 5.2.2.4.

5.8.9.10 Notification Message |R17| p. 319

5.8.9.10.1 General p. 319

Reproduction of 3GPP TS 38.331, Fig. 5.8.9.10.1-1: Notification message in sidelink

Figure 5.8.9.10.1-1: Notification message in sidelink

This procedure is used by a U2N Relay UE to send notification to the connected U2N Remote UE.

5.8.9.10.2 Initiation p. 319

The U2N Relay UE may initiate the procedure when one of the following conditions is met:

1 >

upon Uu RLF as specified in clause 5.3.10;

1 >

upon reception of an RRCReconfiguration including the reconfigurationWithSync;

1 >

upon cell reselection;

1 >

upon L2 U2N Relay UE's RRC connection failure including RRC connection reject as specified in clause 5.3.3.5 and 5.3.13.10, and T300 expiry as specified in clause 5.3.3.7, and RRC resume failure as specified in clause 5.3.13.5;

5.8.9.10.3 Actions related to transmission of NotificationMessageSidelink message p. 319

The U2N Relay UE shall set the indication type as follows:

1 >

if the UE initiates transmission of the NotificationMessageSidelink message due to Uu RLF:

2 >

set the indicationType as relayUE-Uu-RLF;

1 >

else if the UE initiates transmission of the NotificationMessageSidelink message due to reconfiguration with sync:

2 >

set the indicationType as relayUE-HO;

1 >

else if the UE initiates transmission of the NotificationMessageSidelink message due to cell reselection:

2 >

set the indicationType as relayUE-CellReselection;

1 >

if the UE initiates transmission of the NotificationMessageSidelink message due to Uu RRC connection establishment/Resume failure:

2 >

set the indicationType as relayUE-Uu-RRC-Failure;

1 >

submit the NotificationMessageSidelink message to lower layers for transmission.

5.8.9.10.4 Actions related to reception of NotificationMessageSidelink message p. 319

Upon receiving the NotificationMessageSidelink, the U2N Remote UE shall:

1 >

if the indicationType is included:

2 >

if the UE is L2 U2N Remote UE in RRC_CONNECTED:

3 >

if T301 is not running, initiate the RRC connection re-establishment procedure as specified in clause 5.3.7;

2 >

else (the UE is L3 U2N Remote UE, or L2 U2N Remote UE in RRC_IDLE or RRC_INACTIVE):

3 >

if the PC5-RRC connection with the U2N Relay UE is determined to be released:

4 >

indicate upper layers to trigger PC5 unicast link release;

3 >

else (i.e., maintain the PC5 RRC connection):

4 >

if the UE is L2 U2N Remote UE and the indicationType is relayUE-HO or relayUE-CellReselection:

5 >

consider cell re-selection occurs;