Content for TS 38.321 Word version: 18.3.0

1… 4… 5… 5.1.2… 5.2… 5.4… 5.4.4… 5.5… 5.9… 5.18… 5.18.18… 5.19… 5.22… 5.22.1.4… 5.22.2… 5.23… 6… 6.1.3… 6.1.3.8… 6.1.3.11… 6.1.3.17… 6.1.3.21… 6.1.3.26… 6.1.3.31… 6.1.3.37… 6.1.3.42… 6.1.3.49… 6.1.3.53… 6.1.3.59… 6.1.3.64… 6.1.3.70… 6.1.3.74… 6.1.3.79… 6.1.4… 6.2… 7…

5.22 SL-SCH Data transfer and SL-PRS transmission 5.22.1 SL-SCH Data and SL-PRS transmission 5.22.1.1 SL Grant reception and SCI transmission 5.22.1.2 TX resource (re-)selection check 5.22.1.2a Re-evaluation and Pre-emption 5.22.1.2b Re-selection for using a received resource conflict indication 5.22.1.2c Resource re-selection from SL LBT Failure indication 5.22.1.3 Sidelink HARQ operation and SL-PRS transmission 5.22.1.3.1 Sidelink HARQ Entity 5.22.1.3.1a Sidelink process not associated with Dedicated SL-PRS resource pool 5.22.1.3.2 PSFCH reception 5.22.1.3.3 HARQ-based Sidelink RLF detection 5.22.1.3.4 Processing of sidelink grant on Dedicated SL-PRS resource pool 5.22.1.3.5 Sidelink process associated with Dedicated SL-PRS resource pool
...

5.22 SL-SCH Data transfer and SL-PRS transmission |R16| p. 145

5.22.1 SL-SCH Data and SL-PRS transmission p. 145

5.22.1.1 SL Grant reception and SCI transmission p. 145

Sidelink grant is received dynamically on the PDCCH, configured semi-persistently by RRC or autonomously selected by the MAC entity. The MAC entity may have a sidelink grant on an active SL BWP to determine a set of PSCCH duration(s) in which transmission of SCI occurs and a set of PSSCH duration(s) in which transmission of SL-SCH associated with the SCI occurs. The MAC entity may have a sidelink grant on the Shared SL-PRS resource pool of an active BWP to determine a set of PSCCH durations(s) in which transmission of SCI occurs and a set of SL-PRS transmission occasion(s) and PSSCH duration(s) in which transmission of SL-PRS and SL-SCH associated with the SCI occur. The MAC entity may have a sidelink grant on the Dedicated SL-PRS resource pool of an active BWP to determine a set of PSCCH duration(s) in which transmission of SCI occurs and a set of SL-PRS transmission occasion(s) in which transmission of SL-PRS associated to the SCI occurs. A sidelink grant addressed to SL-CS-RNTI with NDI = 1 is considered as a dynamic sidelink grant. A sidelink grant addressed to SL-PRS-CS-RNTI with Activation/Release indication = 1 as in clause 7.3.1.4.3 in TS 38.212 is considered as a dynamic sidelink grant.

If the MAC entity has been configured with Sidelink resource allocation mode 1 as indicated in TS 38.331 or if the MAC entity has been configured with Sidelink resource allocation scheme 1 as indicated in TS 38.331 and PDCCH is received for resource allocation on Shared SL-PRS resource pool, the MAC entity shall for each PDCCH occasion and for each grant received for this PDCCH occasion:

1 >

if a sidelink grant has been received on the PDCCH for the MAC entity's SL-RNTI:

2 >

if the NDI received on the PDCCH has not been toggled compared to the value in the previously received HARQ information for the HARQ Process ID:

3 >

use the received sidelink grant to determine PSCCH duration(s) and PSSCH duration(s) and SL-PRS transmission occasion(s), if available, for one or more retransmissions of a single MAC PDU for the corresponding Sidelink process according to clause 8.1.2 of TS 38.214 and SL-PRS according to clause 8.1.4 of TS 38.214.

2 >

else:

3 >

use the received sidelink grant to determine PSCCH duration(s) and PSSCH duration(s) and SL-PRS transmission occasion(s), if available, for initial transmission and, if available, retransmission(s) of a single MAC PDU and SL-PRS according to clause 8.1.2 of TS 38.214.

1 >

else if a sidelink grant has been received on the PDCCH for the MAC entity's SL-CS-RNTI:

2 >

if PDCCH contents indicate retransmission(s) for the identified HARQ process ID that has been set for an activated configured sidelink grant identified by sl-ConfigIndexCG:

3 >

2 >

else if PDCCH contents indicate configured grant Type 2 deactivation for a configured sidelink grant:

3 >

trigger configured sidelink grant confirmation for the configured sidelink grant.

2 >

else if PDCCH contents indicate configured grant Type 2 activation for a configured sidelink grant:

3 >

trigger configured sidelink grant confirmation for the configured sidelink grant;

3 >

store the configured sidelink grant;

3 >

initialise or re-initialise the configured sidelink grant to determine the set of PSCCH durations and the set of PSSCH durations for transmissions of multiple MAC PDUs according to clause 8.1.2 of TS 38.214 and the set of SL-PRS transmission occasions for transmission of multiple SL-PRS according to clause of 8.2.4 of TS 38.214, if available.

1 >

if a dynamic sidelink grant is available for retransmission(s) of a MAC PDU which has been positively acknowledged as specified in clause 5.22.1.3.1a:

2 >

clear the PSCCH duration(s) and PSSCH duration(s) corresponding to retransmission(s) of the MAC PDU from the sidelink grant.

If the MAC entity has been configured with Sidelink resource allocation scheme 1 as in TS 38.331 and PDCCH is received for resource allocation on SL-PRS Dedicated resource pool, the MAC entity shall for each PDCCH occasion:

1 >

if a sidelink grant has been received on the PDCCH for the MAC entity's SL-PRS-RNTI: (i.e., dynamic grant)

2 >

use the received sidelink grant to determine the PSCCH duration(s) and the corresponding SL-PRS occasion(s) for the transmission of SL-PRS.

1 >

else if a sidelink grant has been received on the PDCCH for MAC entity's SL-PRS-CS-RNTI: (i.e., configured sidelink grant type 2)

2 >

if the PDCCH content indicates the configured grant Type 2 activation for a configured sidelink grant:

3 >

store the configured sidelink grant;

3 >

trigger configured grant confirmation for the configured sidelink grant;

3 >

initialise or re-initialise the configured sidelink grant to determine the set of PSCCH duration(s) and the corresponding SL-PRS occasion for the transmission of SL-PRS.

2 >

else if the PDCCH content indicates the configured Type 2 deactivation for a configured sidelink grant:

3 >

trigger configured grant confirmation for the configured sidelink grant.

If the MAC entity has been configured with Sidelink resource allocation mode 2 to transmit or Sidelink resource allocation scheme 2 using pool(s) of resources in one carrier as indicated in TS 38.331 or TS 36.331 based on full sensing, or partial sensing, or random selection or any combination(s); Or if the MAC entity has been configured with Sidelink resource allocation mode 2 to transmit using pool(s) of resources in multiple carriers as indicated in TS 38.331 based on full sensing, or partial sensing, or random selection or any combination(s), the MAC entity shall for each Sidelink process:

1 >

if the MAC entity has selected to create a selected sidelink grant corresponding to transmissions of multiple MAC PDUs, and SL data is available in a logical channel; or

1 >

if the MAC entity has selected to create a selected sidelink grant corresponding to transmission(s) of multiple SL-PRS(s), which have been triggered by the upper layer or by the reception of a SCI from a peer UE:

2 >

if the MAC entity has not selected a pool of resources allowed for the logical channel or SL-PRS transmission:

3 >

if single carrier frequency is configured:

4 >

if SL data is available in the logical channel for NR sidelink discovery:

5 >

if sl-BWP-DiscPoolConfig or sl-BWP-DiscPoolConfigCommon is configured according to TS 38.331:

6 >

select the sl-DiscTxPoolSelected configured in sl-BWP-DiscPoolConfig or sl-BWP-DiscPoolConfigCommon for the transmission of NR sidelink discovery message.

5 >

else:

6 >

select any pool of resources among the configured pools of resources except for SL-PRS Dedicated resource pool, if configured.

4 >

else if SL data is available in the logical channel for BRID for A2X communication:

5 >

if sl-BWP-PoolConfigA2X or sl-BWP-PoolConfigCommonA2X is configured according to TS 38.331:

6 >

if resource pool(s) is configured with sl-A2X-Service indicating brid or bridAndDAA:

7 >

select any pool of resources among the resource pool(s) configured with sl-A2X-Service indicating brid or bridAndDAA in sl-TxPoolSelectedNormal configured in sl-BWP-PoolConfigA2X or sl-BWP-PoolConfigCommonA2X for the transmission of SL data for A2X communication.

6 >

else:

7 >

select any pool of resources among the configured pools of resources except the pool(s) in sl-BWP-PoolConfigA2X, sl-BWP-PoolConfigCommonA2X, sl-BWP-DiscPoolConfig or sl-BWP-DiscPoolConfigCommon, if configured or Dedicated SL-PRS resource pool, if configured.

5 >

else:

6 >

select any pool of resources among the configured pools of resources except the pool(s) in sl-BWP-DiscPoolConfig or sl-BWP-DiscPoolConfigCommon, if configured or Dedicated SL-PRS resource pool, if configured.

4 >

else if SL data is available in the logical channel for DAA for A2X communication:

5 >

if sl-BWP-PoolConfigA2X or sl-BWP-PoolConfigCommonA2X is configured according to TS 38.331:

6 >

if resource pool(s) is configured with sl-A2X-Service indicating daa or bridAndDAA:

7 >

select any pool of resources among the resource pool(s) configured with sl-A2X-Service indicating daa or bridAndDAA in sl-TxPoolSelectedNormal configured in sl-BWP-PoolConfigA2X or sl-BWP-PoolConfigCommonA2X for the transmission of SL data for A2X communication.

6 >

else:

7 >

5 >

else:

6 >

4 >

else if sl-HARQ-FeedbackEnabled is set to enabled for the logical channel:

5 >

select any pool of resources configured with PSFCH resources among the pools of resources except the pool(s) in sl-BWP-DiscPoolConfig, sl-BWP-DiscPoolConfigCommon, sl-BWP-PoolConfigA2X or sl-BWP-PoolConfigCommonA2X, if configured or SL-PRS Dedicated resource pool, if configured.

4 >

else if SL-PRS is pending for transmission:

5 >

select any resource pool among the resource pool(s) allowing for SL-PRS transmission.

4 >

else:

5 >

select any pool of resources among the pools of resources except the pool(s) in sl-BWP-DiscPoolConfig, sl-BWP-DiscPoolConfigCommon, sl-BWP-PoolConfigA2X or sl-BWP-PoolConfigCommonA2X, if configured or SL-PRS Dedicated resource pool, if configured.

3 >

else (i.e. multiple carrier frequencies are configured):

4 >

trigger the TX carrier (re-)selection procedure as specified in clause 5.22.1.11.

2 >

if Sidelink consistent LBT failure is detected as specified in clause 5.31.2 in all RB sets of the selected resource pool, if single carrier frequency is configured:

3 >

if sl-HARQ-FeedbackEnabled is set to enabled for the logical channel:

4 >

select any pool of resources configured with PSFCH resources among the pools of resources except the pool(s) in sl-BWP-DiscPoolConfig or sl-BWP-DiscPoolConfigCommon, if configured and the pool(s) in which all RB sets had Sidelink consistent LBT failure detected and not cancelled.

3 >

else:

4 >

select any pool of resources among the pools of resources except the pool(s) in sl-BWP-DiscPoolConfig or sl-BWP-DiscPoolConfigCommon, if configured and the pool(s) in which all RB sets had Sidelink consistent LBT failure detected and not cancelled.

2 >

perform the TX resource (re-)selection check on the selected pool of resources as specified in clause 5.22.1.2;

2 >

if the TX resource (re-)selection is triggered as the result of the TX resource (re-)selection check:

3 >

if sl-lbt-FailureRecoveryConfig is configured in the SL BWP:

4 >

indicate to the physical layer RB set information for which Sidelink consistent LBT failure was detected and not cancelled as specified in clause 5.31.2.

3 >

if the TX carrier (re-)selection procedure was triggered in above and one or more carriers have been (re-)selected in the TX carrier (re-)selection according to clause 5.22.1.11:

4 >

determine the order of the (re-)selected carriers, according to the decreasing order based on the highest priority of logical channels which are allowed on each (re-)selected carrier, and perform the resource selection procedure as specified in this clause for each Sidelink process on each (re-)selected carrier according to the order.

3 >

if one or multiple SL DRX(s) is configured in the destination UE(s) receiving SL-SCH data:

4 >

indicate to the physical layer SL DRX Active time in the destination UE(s) receiving SL-SCH data, as specified in clause 5.28.2.

3 >

randomly select, with equal probability, an integer value in the interval [5, 15] for the resource reservation interval higher than or equal to 100ms or in the interval formula#1 in §5.22.1.1

for the resource reservation interval lower than 100ms and set SL_RESOURCE_RESELECTION_COUNTER to the selected value;

3 >

if the selected resource pool is not SL-PRS Dedicated resource pool:

4 >

select one of the allowed values configured by RRC in sl-ResourceReservePeriodList and set the resource reservation interval, Prsvp_TX, with the selected value;

4 >

select the number of HARQ retransmissions from the allowed numbers, if configured by RRC, in sl-MaxTxTransNumPSSCH included in sl-PSSCH-TxConfigList and, if configured by RRC, overlapped in sl-MaxTxTransNumPSSCH indicated in sl-CBR-PriorityTxConfigList for the highest priority of the logical channel(s) and pending SL-PRS transmission(s), if available, allowed on the carrier and the CBR measured by lower layers according to clause 5.1.27 of TS 38.215 if CBR measurement results are available or the corresponding sl-DefaultTxConfigIndex configured by RRC if CBR measurement results are not available or the corresponding sl-DefaultCBR-PartialSensing configured by RRC if partial sensing is selected and CBR measurement results are not available, or the corresponding sl-DefaultCBR-RandomSelection configured by RRC if random selection is selected and CBR measurement results are not available in case the sl-TxPoolExceptional is not used;

4 >

select an amount of frequency resources within the range, if configured by RRC, between sl-MinSubChannelNumPSSCH and sl-MaxSubchannelNumPSSCH included in sl-PSSCH-TxConfigList and, if configured by RRC, overlapped between sl-MinSubChannelNumPSSCH and sl-MaxSubchannelNumPSSCH indicated in sl-CBR-PriorityTxConfigList for the highest priority of the logical channel(s) and pending SL-PRS transmission(s), if available, allowed on the carrier and the CBR measured by lower layers according to clause 5.1.27 of TS 38.215 if CBR measurement results are available or the corresponding sl-DefaultTxConfigIndex configured by RRC if CBR measurement results are not available or the corresponding sl-DefaultCBR-PartialSensing configured by RRC if partial sensing is selected and CBR measurement results are not available, or the corresponding sl-DefaultCBR-RandomSelection configured by RRC if random selection is selected and CBR measurement results are not available in case the sl-TxPoolExceptional is not used;

3 >

else if the selected resource pool is SL-PRS Dedicated resource pool:

4 >

select one of the allowed values configured by RRC in sl-PRS-ResourceReservePeriodList and set the resource reservation interval, P_"rsvp_TX" , with the selected value;

4 >

select the number of SL-PRS retransmissions from the allowed numbers, if configured by RRC, in sl-PRS-MaxNum-Transmissions included in sl-CBR-SL-PRS-TxConfigList.

3 >

if sl-InterUE-CoordinationScheme1 enabling reception/transmission of preferred resource set and non-preferred resource set is not configured by RRC:

4 >

if transmission based on random selection is configured by upper layers:

5 >

if the selected resource pool is not SL-PRS Dedicated resource pool:

6 >

randomly select the time and frequency resources for one transmission opportunity from the resource pool which occur within the SL DRX Active time, if configured, as specified in clause 5.28.2 of the destination UE selected for indicating to the physical layer the SL DRX Active time above, and the pool(s) in which all RB sets had Sidelink consistent LBT failure detected and not cancelled and the resources of which the lowest sub-channel includes intra cell guard band PRBs if sl-transmissionStructureForPSCCHandPSSCH is set to 'contiguousRB' are excluded, if configured, according to the amount of selected frequency resources, the remaining PDB of SL data available in the logical channel(s), and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, allowed on the carrier.

5 >

else if the selected resource pool is SL-PRS Dedicated resource pool:

6 >

randomly select the time and frequency resources for one transmission opportunity from the resource pool, according to the remaining SL-PRS delay budget of the SL-PRS transmission(s).

4 >

else:

5 >

if sl-NRPSSCH-EUTRA-ThresRSRP-List is configured by the RRC:

6 >

when SCS of NR SL is (pre-)configured as μ = 0:

7 >

6 >

when SCS of NR SL is (pre-)configured as μ = 1:

7 >

randomly select the time and frequency resources in the first of NR SL slots overlapping with an LTE SL subframe for one transmission opportunity from the resources indicated by the physical layer as specified in clause 8.1.4 of TS 38.214 which occur within the SL DRX Active time, if configured, as specified in clause 5.28.2 of the destination UE selected for indicating to the physical layer the SL DRX Active time above, according to the amount of selected frequency resources and the remaining PDB of SL data available in the logical channel(s) allowed on the carrier.

5 >

else if the selected resource pool is not SL-PRS Dedicated resource pool:

6 >

randomly select the time and frequency resources for one transmission opportunity from the resources indicated by the physical layer as specified in clause 8.1.4 of TS 38.214 which occur within the SL DRX Active time, if configured, as specified in clause 5.28.2 of the destination UE selected for indicating to the physical layer the SL DRX Active time above, according to the amount of selected frequency resources, the remaining PDB of SL data available in the logical channel(s), and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, allowed on the carrier.

5 >

else if the selected resource pool is SL-PRS Dedicated resource pool:

6 >

randomly select the time and frequency resources for one transmission opportunity from the resources indicated by physical layer as clasue 8.2.4 of TS 38.214, according to the remaining SL-PRS delay budget of the SL-PRS transmission(s).

3 >

if sl-InterUE-CoordinationScheme1 enabling reception/transmission of preferred resource set and non-preferred resource set is configured by RRC and preferred resource set is not received from a UE:

4 >

if transmission based on random selection is configured by upper layers:

5 >

if the selected resource pool is not SL-PRS Dedicated resource pool:

6 >

randomly select the time and frequency resources for one transmission opportunity from the resource pool excluding all RB sets had Sidelink consistent LBT failure detected and not cancelled and the resources of which the lowest sub-channel includes intra cell guard band PRBs if sl-transmissionStructureForPSCCHandPSSCH is set to 'contiguousRB' are excluded, if configured, according to the amount of selected frequency resources, the remaining PDB of SL data available in the logical channel(s), and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, allowed on the carrier.

5 >

else if the selected resource pool is SL-PRS Dedicated resource pool:

6 >

andomly select the time and frequency resources for one transmission opportunity from the resource pool, according to the remaining SL-PRS delay budget of the SL-PRS transmission(s).

4 >

else:

5 >

if the selected resource pool is not SL-PRS Dedicated resource pool:

6 >

randomly select the time and frequency resources for one transmission opportunity from the resources indicated by the physical layer as specified in clause 8.1.4 of TS 38.214, according to the amount of selected frequency resources, the remaining PDB of SL data available in the logical channel(s), and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, allowed on the carrier.

5 >

else if the selected resource pool is SL-PRS Dedicated resource pool:

6 >

randomly select the time and frequency resources for one transmission opportunity from the resources indicated by physical layer as clause 8.2.4 of TS 38.214, according to the remaining SL-PRS delay budget of the SL-PRS transmission.

3 >

if sl-InterUE-CoordinationScheme1 enabling reception/transmission of preferred resource set and non-preferred resource set is configured by RRC and when the UE does not have its own sensing result as specified in clause 8.1.4 of TS 38.214 and if a preferred resource set is received from a UE and if the selected resource pool is not SL-PRS Dedicated resource pool:

4 >

randomly select the time and frequency resources for one transmission opportunity from the resources belonging to the received preferred resource set for SL-SCH data to be transmitted to the UE providing the preferred resource set, according to the amount of selected frequency resources and the remaining PDB of SL data available in the logical channel(s), and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, allowed on the carrier.

3 >

if sl-InterUE-CoordinationScheme1 enabling reception/transmission of preferred resource set and non-preferred resource set is configured by RRC and when the UE has its own sensing result as specified in clause 8.1.4 of TS 38.214 and if a preferred resource set is received from a UE and if the selected resource pool is not SL-PRS Dedicated resource pool:

4 >

randomly select the time and frequency resources for one transmission opportunity within the intersection of the received preferred resource set and the resources indicated by the physical layer as specified in clause 8.1.4 of TS 38.214 for an SL-SCH data to be transmitted to the UE providing the preferred resource set, according to the amount of selected frequency resources, the remaining PDB of SL data available in the logical channel(s), and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, allowed on the carrier.

4 >

if there are no resources within the intersection that can be selected as the time and frequency resources for the one transmission opportunity according to the amount of selected frequency resources and the remaining PDB of SL data available in the logical channel(s) allowed on the carrier.

5 >

3 >

use the randomly selected resource to select a set of periodic resources spaced by the resource reservation interval for transmissions of PSCCH, PSSCH and SL-PRS corresponding to the number of transmission opportunities of MAC PDUs or SL-PRSs determined in TS 38.214.

3 >

if one or more SL-PRS retransmissions are selected and the selected resource pool is SL-PRS Dedicated resource pool:

4 >

randomly select the time and frequency resources for one or more transmission opportunities from the available resources, according to the selected number of retransmissions and the remaining SL-PRS delay budget and that a retransmission resource can be indicated by the time resource assignment of a prior SCI according to clause 8.3.1.1 of TS 38.212;

4 >

use the randomly selected resource to select a set of periodic resources spaced by the resource reservation interval for transmissions of PSCCH and SL-PRS corresponding to the number of retransmission opportunities of SL-PRS;

4 >

consider the first set of transmission opportunities as the initial transmission opportunities and the other set(s) of transmission opportunities as the retransmission opportunities;

4 >

consider the sets of initial transmission opportunities and retransmission opportunities as the selected sidelink grant.

3 >

else if one or more HARQ retransmissions are selected and the selected resource pool is not SL-PRS Dedicated resource pool:

4 >

if sl-InterUE-CoordinationScheme1 enabling reception/transmission of preferred resource set and non-preferred resource set is not configured by RRC:

5 >

if transmission based on full sensing or partial sensing is configured by upper layers and there are available resources left in the resources indicated by the physical layer according to clause 8.1.4 of TS 38.214 for more transmission opportunities; or

5 >

if transmission based on random selection is configured by upper layers and there are available resources left in the resource pool for more transmission opportunities:

6 >

if sl-NRPSSCH-EUTRA-ThresRSRP-List is configured by the RRC:

7 >

when SCS of NR SL is (pre-)configured as μ = 0:

8 >

7 >

when SCS of NR SL is (pre-)configured as μ = 1:

8 >

randomly select the time and frequency resources in the second of NR SL slots of NR SL slots overlapping with an LTE SL subframe to which the selected transmission resources belongs, or select the time and frequency resources in the first of NR SL slots overlapping with an LTE SL subframe for one or more transmission opportunities from the available resources which occur within the SL DRX Active time, if configured, as specified in clause 5.28.2 of the destination UE selected for indicating to the physical layer the SL DRX Active time above, according to the amount of selected frequency resources, the selected number of HARQ retransmissions and the remaining PDB of SL data available in the logical channel(s) allowed on the carrier by ensuring the minimum time gap between any two selected resources in case that PSFCH is configured for this pool of resources and that a retransmission resource can be indicated by the time resource assignment of a prior SCI according to clause 8.3.1.1 of TS 38.212.

6 >

else:

7 >

randomly select the time and frequency resources for one or more transmission opportunities from the available resources which occur within the SL DRX Active time, if configured, as specified in clause 5.28.2 of the destination UE selected for indicating to the physical layer the SL DRX Active time above, and the pool(s) in which all RB sets with Sidelink consistent LBT failure detected and not cancelled and the resources of which the lowest sub-channel includes intra cell guard band PRBs if sl-transmissionStructureForPSCCHandPSSCH is set to 'contiguousRB' are excluded, if configured, according to the amount of selected frequency resources, the selected number of HARQ retransmissions, the remaining PDB of SL data available in the logical channel(s), and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, allowed on the carrier by ensuring the minimum time gap between any two selected resources in case that PSFCH is configured for this pool of resources and that a retransmission resource can be indicated by the time resource assignment of a prior SCI according to clause 8.3.1.1 of TS 38.212.

4 >

if sl-InterUE-CoordinationScheme1 enabling reception/transmission of preferred resource set and non-preferred resource set is configured by RRC and preferred resource set is not received from a UE:

5 >

if transmission based on random selection is configured by upper layers and there are available resources left in the resource pool for more transmission opportunities:

6 >

randomly select the time and frequency resources for one or more transmission opportunities from the available resources excluding all RB sets had Sidelink consistent LBT failure detected and not cancelled and the resources of which the lowest sub-channel includes intra cell guard band PRBs if sl-transmissionStructureForPSCCHandPSSCH is set to 'contiguousRB' are excluded, if configured according to the amount of selected frequency resources, the selected number of HARQ retransmissions, the remaining PDB of SL data available in the logical channel(s), and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, allowed on the carrier by ensuring the minimum time gap between any two selected resources in case that PSFCH is configured for this pool of resources and that a retransmission resource can be indicated by the time resource assignment of a prior SCI according to clause 8.3.1.1 of TS 38.212.

4 >

if sl-InterUE-CoordinationScheme1 enabling reception/transmission of preferred resource set and non-preferred resource set is configured by RRC and when the UE has own sensing result as specified in clause 8.1.4 of TS 38.214 and if a preferred resource set is received from a UE:

5 >

if there are available resources left in the intersection of the received preferred resource set and the resources indicated by the physical layer as specified in clause 8.1.4 of TS 38.214 for more transmission opportunities:

6 >

randomly select the time and frequency resources for one or more transmission opportunities from the available resources within the intersection for SL-SCH data to be transmitted to the UE providing the preferred resource set, according to the amount of selected frequency resources, the selected number of HARQ retransmissions, the remaining PDB of SL data available in the logical channel(s) , and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, allowed on the carrier by ensuring the minimum time gap between any two selected resources in case that PSFCH is configured for this pool of resources and that a retransmission resource can be indicated by the time resource assignment of a prior SCI according to clause 8.3.1.1 of TS 38.212.

5 >

if the number of time and frequency resources that has been maximally selected for one or more transmission opportunities from the available resources within the intersection is smaller than the selected number of HARQ retransmissions and there are available resources left in the resources indicated by the physical layer for more transmission opportunities:

6 >

randomly select the time and frequency resources for the remaining transmission opportunities except for the selected resources within the intersection from the available resources outside the intersection but left in the resources indicated by the physical layer according to clause 8.1.4 of TS 38.214, according to the amount of selected frequency resources, the selected number of HARQ retransmissions, the remaining PDB of SL data available in the logical channel(s), and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, allowed on the carrier by ensuring the minimum time gap between any two selected resources in case that PSFCH is configured for this pool of resources and that a retransmission resource can be indicated by the time resource assignment of a prior SCI according to clause 8.3.1.1 of TS 38.212.

4 >

if sl-InterUE-CoordinationScheme1 enabling reception/transmission of preferred resource set and non-preferred resource set is configured by RRC and when the UE does not have own sensing result as specified in clause 8.1.4 of TS 38.214 and if a preferred resource set is received from a UE; and

4 >

if there are available resources left in the received preferred resource set for more transmission opportunities:

5 >

randomly select the time and frequency resources for one or more transmission opportunities from the available resources belonging to the received preferred resource set for SL-SCH data to be transmitted to the UE providing the preferred resource set, according to the amount of selected frequency resources, the selected number of HARQ retransmissions, the remaining PDB of SL data available in the logical channel(s), and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, allowed on the carrier by ensuring the minimum time gap between any two selected resources in case that PSFCH is configured for this pool of resources and that a retransmission resource can be indicated by the time resource assignment of a prior SCI according to clause 8.3.1.1 of TS 38.212.

4 >

use the randomly selected resource to select a set of periodic resources spaced by the resource reservation interval for transmissions of PSCCH, PSSCH, if available and SL-PRS, if available corresponding to the number of retransmission opportunities of the MAC PDUs determined in TS 38.214 or SL-PRS(s);

4 >

consider the first set of transmission opportunities as the initial transmission opportunities and the other set(s) of transmission opportunities as the retransmission opportunities;

4 >

consider the sets of initial transmission opportunities and retransmission opportunities as the selected sidelink grant.

3 >

else:

4 >

consider the set as the selected sidelink grant.

3 >

use the selected sidelink grant to determine the set of PSCCH durations and the set of PSSCH durations and the set of SL-PRS transmission occasion(s), if available, according to TS 38.214 if the selected resource pool is not SL-PRS Dedicated resource pool or to determine the set of PSCCH durations and SL-PRS transmission occasion(s) if the selected resource pool is SL-PRS Dedicated resource pool according to TS 38.214.

2 >

else if SL_RESOURCE_RESELECTION_COUNTER = 0 and when SL_RESOURCE_RESELECTION_COUNTER was equal to 1 the MAC entity randomly selected, with equal probability, a value in the interval [0, 1] which is less than or equal to the probability configured by RRC in sl-ProbResourceKeep:

3 >

clear the selected sidelink grant, if available;

3 >

randomly select, with equal probability, an integer value in the interval [5, 15] for the resource reservation interval higher than or equal to 100ms or in the interval formula#2 in §5.22.1.1

for the resource reservation interval lower than 100ms and set SL_RESOURCE_RESELECTION_COUNTER to the selected value;

3 >

reuse the previously selected sidelink grant for the number of transmissions of the MAC PDUs or SL-PRS(s) determined in TS 38.214 with the resource reservation interval to determine the set of PSCCH durations, the set of PSSCH durations, and the pending SL-PRS transmission(s), if available, according to TS 38.214.

1 >

if the MAC entity has selected to create a selected sidelink grant corresponding to transmission(s) of a single MAC PDU, and if SL data is available in a logical channel, or an SL-CSI reporting is triggered, or a Sidelink DRX Command indication is triggered or a Sidelink Inter-UE Coordination Information reporting is triggered, or a Sidelink Inter-UE Coordination Request is triggered; or

1 >

if the MAC entity has selected to create a selected sidelink grant corresponding to transmission of a single SL-PRS, which has been triggered by the upper layer or by the reception of a SCI from a peer UE:

2 >

if single carrier frequency is configured:

3 >

if SL data is available in the logical channel for NR sidelink discovery:

4 >

if sl-BWP-DiscPoolConfig or sl-BWP-DiscPoolConfigCommon is configured according to TS 38.331:

5 >

select the sl-DiscTxPoolSelected configured in sl-BWP-DiscPoolConfig or sl-BWP-DiscPoolConfigCommon for the transmission of NR sidelink discovery message.

4 >

else:

5 >

select any pool of resources among the configured pools of resources except for SL-PRS Dedicated resource pool, if configured.

3 >

else if SL data is available in the logical channel for BRID for A2X communication:

4 >

if sl-BWP-PoolConfigA2X or sl-BWP-PoolConfigCommonA2X is configured according to TS 38.331:

5 >

if resource pool(s) is configured with sl-A2X-Service indicating brid or bridAndDAA:

6 >

5 >

else:

6 >

4 >

else:

5 >

3 >

else if SL data is available in the logical channel for DAA for A2X communication:

4 >

if sl-BWP-PoolConfigA2X or sl-BWP-PoolConfigCommonA2X is configured according to TS 38.331:

5 >

if resource pool(s) is configured with sl-A2X-Service indicating daa or bridAndDAA:

6 >

5 >

else:

6 >

4 >

else:

5 >

3 >

else if SL data for NR sidelink communication is available in the logical channel:

4 >

if sl-HARQ-FeedbackEnabled is set to enabled for the logical channel:

5 >

4 >

else:

5 >

3 >

else if SL-PRS is pending for transmission:

4 >

select any resource pool among the resource pool(s) allowing for SL-PRS transmission.

3 >

else if an SL-CSI reporting or a Sidelink DRX Command or a Sidelink Inter-UE Coordination Request or a Sidelink Inter-UE Coordination Information is triggered:

4 >

2 >

else (i.e. multiple carrier frequencies are configured):

3 >

trigger the TX carrier (re-)selection procedure as specified in clause 5.22.1.11.

2 >

if Sidelink consistent LBT Failure is detected as specified in clause 5.31.2 in all RB sets of the selected resource pool for the logical channel, if single carrier frequency is configured:

3 >

clear the selected sidelink grant on the selected pool of resources.

3 >

if sl-HARQ-FeedbackEnabled is set to enabled for the logical channel:

4 >

select any pool of resources configured with PSFCH resources among the pools of resources except the pool(s) in sl-BWP-DiscPoolConfig or sl-BWP-DiscPoolConfigCommon, if configured and the pool(s) including all RB sets for which Sidelink consistent LBT failures were detected and not cancelled.

3 >

else:

4 >

select any pool of resources among the pools of resources except the pool(s) in sl-BWP-DiscPoolConfig or sl-BWP-DiscPoolConfigCommon, if configured and the pool(s) including all RB sets for which Sidelink consistent LBT failures were detected and not cancelled.

2 >

perform the TX resource (re-)selection check on the selected pool of resources as specified in clause 5.22.1.2;

2 >

if the TX resource (re-)selection is triggered as the result of the TX resource (re-)selection check

3 >

if sl-lbt-FailureRecoveryConfig is configured in the SL BWP:

4 >

indicate to the physical layer RB set information for which Sidelink consistent LBT failure was detected and not cancelled as specified in clause 5.31.2.

3 >

if the TX carrier (re-)selection procedure was triggered in above and one or more carriers have been (re-)selected in the Tx carrier (re-)selection according to clause 5.22.1.11:

4 >

3 >

if one or multiple SL DRX(s) is configured in the destination UE(s) receiving SL-SCH data:

4 >

indicate to the physical layer SL DRX Active time in the destination UE(s) receiving SL-SCH data, as specified in clause 5.28.2.

3 >

if the selected resource pool is not SL-PRS Dedicated resource pool:

4 >

select the number of HARQ retransmissions from the allowed numbers, if configured by RRC, in sl-MaxTxTransNumPSSCH included in sl-PSSCH-TxConfigList and, if configured by RRC, overlapped in sl-MaxTxTransNumPSSCH indicated in sl-CBR-PriorityTxConfigList for the highest priority of the logical channel(s) and pending SL-PRS transmission(s), if available allowed on the carrier and the CBR measured by lower layers according to clause 5.1.27 of TS 38.215 if CBR measurement results are available or the corresponding sl-DefaultTxConfigIndex configured by RRC if CBR measurement results are not available or the corresponding sl-DefaultCBR-PartialSensing configured by RRC if partial sensing is selected and CBR measurement results are not available, or the corresponding sl-DefaultCBR-RandomSelection configured by RRC if random selection is selected and CBR measurement results are not available in case the sl-TxPoolExceptional is not used;

4 >

select an amount of frequency resources within the range, if configured by RRC, between sl-MinSubChannelNumPSSCH and sl-MaxSubChannelNumPSSCH included in sl-PSSCH-TxConfigList and, if configured by RRC, overlapped between sl-MinSubChannelNumPSSCH and sl-MaxSubChannelNumPSSCH indicated in sl-CBR-PriorityTxConfigList for the highest priority of the logical channel(s) and pending SL-PRS transmission(s), if available allowed on the carrier and the CBR measured by lower layers according to clause 5.1.27 of TS 38.215 if CBR measurement results are available or the corresponding sl-DefaultTxConfigIndex configured by RRC if CBR measurement results are not available or the corresponding sl-DefaultCBR-PartialSensing configured by RRC if partial sensing is selected and CBR measurement results are not available, or the corresponding sl-DefaultCBR-RandomSelection configured by RRC if random selection is selected and CBR measurement results are not available in case the sl-TxPoolExceptional is not used;

3 >

if the selected resource pool is SL-PRS Dedicated resource pool:

4 >

select the number of SL-PRS retransmissions from the allowed numbers, if configured by RRC, in sl-PRS-MaxNum-Transmissions included in sl-CBR-SL-PRS-TxConfigList.

3 >

if sl-InterUE-CoordinationScheme1 enabling reception/transmission of preferred resource set and non-preferred resource set is not configured by RRC:

4 >

if transmission based on random selection is configured by upper layers:

5 >

if the selected resource pool is not SL-PRS Dedicated resource pool:

6 >

5 >

if the selected resource pool is SL-PRS Dedicated resource pool:

6 >

randomly select the time and frequency resources for one transmission opportunity from the resource pool, according to the remaining SL-PRS delay budget of the SL-PRS transmission.

4 >

else:

5 >

if sl-NRPSSCH-EUTRA-ThresRSRP-List is configured by the RRC:

6 >

when SCS of NR SL is (pre-)configured as μ = 0:

7 >

6 >

when SCS of NR SL is (pre-)configured as μ = 1:

7 >

5 >

else if the selected resource pool is not SL-PRS Dedicated resource pool:

6 >

5 >

if the selected resource pool is SL-PRS Dedicated resource pool:

6 >

3 >

if sl-InterUE-CoordinationScheme1 enabling reception/transmission of preferred resource set and non-preferred resource set is configured by RRC and preferred resource set is not received from a UE:

4 >

if transmission based on random selection is configured by upper layers:

5 >

if the selected resource pool is not SL-PRS Dedicated resource pool:

6 >

randomly select the time and frequency resources for one transmission opportunity from the resource pool excluding all RB sets had Sidelink consistent LBT failure detected and not cancelled and the resources of which the lowest sub-channel includes intra cell guard band PRBs if sl-transmissionStructureForPSCCHandPSSCH is set to 'contiguousRB' are excluded, if configured according to the amount of selected frequency resources and the remaining PDB of SL data available in the logical channel(s), and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, allowed on the carrier, and/or the latency requirement of the triggered SL-CSI reporting.

4 >

else:

5 >

if the selected resource pool is not SL-PRS Dedicated resource pool:

6 >

3 >

if sl-InterUE-CoordinationScheme1 enabling reception/transmission of preferred resource set and non-preferred resource set is configured by RRC and when the UE does not have own sensing result as specified in clause 8.1.4 of TS 38.214 and if a preferred resource set is received from a UE and if the selected resource pool is not SL-PRS Dedicated resource pool:

4 >

randomly select the time and frequency resources for one transmission opportunity from the resources belonging to the received preferred resource set for a MAC PDU to be transmitted to the UE providing the preferred resource set, according to the amount of selected frequency resources, the remaining PDB of SL data available in the logical channel(s), and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, allowed on the carrier, and/or the latency requirement of the triggered SL-CSI reporting.

3 >

4 >

randomly select the time and frequency resources for one transmission opportunity within the intersection of the received preferred resource set and the resources indicated by the physical layer as specified in clause 8.1.4 of TS 38.214 for a MAC PDU to be transmitted to the UE providing the preferred resource set, according to the amount of selected frequency resources, the remaining PDB of SL data available in the logical channel(s), and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, allowed on the carrier, and/or the latency requirement of the triggered SL-CSI reporting;

4 >

5 >

3 >

if sl-InterUE-CoordinationScheme1 enabling reception/transmission of preferred resource set and non-preferred resource set is configured by RRC and when the UE determines the resources for Sidelink Inter-UE Coordination Information transmission upon explicit request from a UE:

4 >

randomly select the time and frequency resources for one transmission opportunity from the resources indicated by the physical layer as specified in clause 8.1.4 of TS 38.214, according to the amount of selected frequency resources, the remaining PDB of SL data available in the logical channel(s) allowed on the carrier, and/or the latency requirement of the triggered SL-CSI reporting and the latency requirement of the Sidelink Inter-UE Coordination Information transmission, and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available.

3 >

if one or more SL-PRS retransmissions are selected and the selected resource pool is SL-PRS Dedicated resource pool:

4 >

consider the first set of transmission opportunities as the initial transmission opportunities and the other set(s) of transmission opportunities as the retransmission opportunities;

4 >

consider the sets of initial transmission opportunities and retransmission opportunities as the selected sidelink grant.

3 >

else if one or more HARQ retransmissions are selected and the selected resource pool is not SL-PRS Dedicated resource pool:

4 >

if sl-InterUE-CoordinationScheme1 enabling reception/transmission of preferred resource set and non-preferred resource set is not configured by RRC:

5 >

if transmission based on random selection is configured by upper layers and there are available resources left in the resource pool for more transmission opportunities:

6 >

if sl-NRPSSCH-EUTRA-ThresRSRP-List is configured by the RRC:

7 >

when SCS of NR SL is (pre-)configured as μ = 0:

8 >

randomly select the time and frequency resources for one transmission opportunity from the resources indicated by the physical layer as specified in clause 8.1.4 of TS 38.214 which occur within the SL DRX Active time, if configured, as specified in clause 5.28.2 of the destination UE selected for indicating to the physical layer the SL DRX Active time above, according to the amount of selected frequency resources and the remaining PDB of SL data available in the logical channel(s) allowed on the carrier, and/or the latency requirement of the triggered SL-CSI by ensuring the minimum time gap between any two selected resources in case that PSFCH is configured for this pool of resources, and that a retransmission resource can be indicated by the time resource assignment of a prior SCI according to clause 8.3.1.1 of TS 38.212.

7 >

when SCS of NR SL is (pre-)configured as μ = 1:

8 >

randomly select the time and frequency resources in the second of NR SL slots of NR SL slots overlapping with an LTE SL subframe to which the selected transmission resources belongs, or select the time and frequency resources in the first of NR SL slots overlapping with an LTE SL subframe for one transmission opportunity from the resources indicated by the physical layer as specified in clause 8.1.4 of TS 38.214 which occur within the SL DRX Active time, if configured, as specified in clause 5.28.2 of the destination UE selected for indicating to the physical layer the SL DRX Active time above, according to the amount of selected frequency resources and the remaining PDB of SL data available in the logical channel(s) allowed on the carrier, and/or the latency requirement of the triggered SL-CSI by ensuring the minimum time gap between any two selected resources in case that PSFCH is configured for this pool of resources, and that a retransmission resource can be indicated by the time resource assignment of a prior SCI according to clause 8.3.1.1 of TS 38.212.

6 >

else:

7 >

randomly select the time and frequency resources for one or more transmission opportunities from the available resources which occur within the SL DRX Active time, if configured, as specified in clause 5.28.2 of the destination UE selected for indicating to the physical layer the SL DRX Active time above, and the pool(s) in which all RB sets with Sidelink consistent LBT failure detected and not cancelled and the resources of which the lowest sub-channel includes intra cell guard band PRBs if sl-transmissionStructureForPSCCHandPSSCH is set to 'contiguousRB' are excluded, if configured, according to the amount of selected frequency resources, the selected number of HARQ retransmissions and the remaining PDB of SL data available in the logical channel(s) allowed on the carrier, and/or the latency requirement of the triggered SL-CSI reporting, and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, by ensuring the minimum time gap between any two selected resources in case that PSFCH is configured for this pool of resources, and that a retransmission resource can be indicated by the time resource assignment of a prior SCI according to clause 8.3.1.1 of TS 38.212;

4 >

if sl-InterUE-CoordinationScheme1 enabling reception/transmission of preferred resource set and non-preferred resource set is configured by RRC and preferred resource set is not received from a UE:

5 >

if transmission based on sensing is configured by upper layers and there are available resources left in the resources indicated by the physical layer according to clause 8.1.4 of TS 38.214 for more transmission opportunities; or

5 >

if transmission based on random selection is configured by upper layers and there are available resources left in the resource pool for more transmission opportunities:

6 >

randomly select the time and frequency resources for one or more transmission opportunities from the available resources excluding all RB sets had Sidelink consistent LBT failure detected and not cancelled and the resources of which the lowest sub-channel includes intra cell guard band PRBs if sl-transmissionStructureForPSCCHandPSSCH is set to 'contiguousRB' are excluded, if configured according to the amount of selected frequency resources, the selected number of HARQ retransmissions and the remaining PDB of SL data available in the logical channel(s) allowed on the carrier, and/or the latency requirement of the triggered SL-CSI reporting, and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, by ensuring the minimum time gap between any two selected resources in case that PSFCH is configured for this pool of resources and that a retransmission resource can be indicated by the time resource assignment of a prior SCI according to clause 8.3.1.1 of TS 38.212.

4 >

5 >

6 >

randomly select the time and frequency resources for one or more transmission opportunities from the available resources within the intersection for a MAC PDU to be transmitted to the UE providing the preferred resource set, according to the amount of selected frequency resources, the selected number of HARQ retransmissions and the remaining PDB of SL data available in the logical channel(s) allowed on the carrier, and/or the latency requirement of the triggered SL-CSI reporting, and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, by ensuring the minimum time gap between any two selected resources in case that PSFCH is configured for this pool of resources and that a retransmission resource can be indicated by the time resource assignment of a prior SCI according to clause 8.3.1.1 of TS 38.212.

5 >

6 >

randomly select the time and frequency resources for the remaining transmission opportunities except for the selected resources within the intersection from the available resources outside the intersection but left in the resources indicated by the physical layer according to clause 8.1.4 of TS 38.214, according to the amount of selected frequency resources, the selected number of HARQ retransmissions and the remaining PDB of SL data available in the logical channel(s) allowed on the carrier, and/or the latency requirement of the triggered SL-CSI reporting, and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, by ensuring the minimum time gap between any two selected resources in case that PSFCH is configured for this pool of resources and that a retransmission resource can be indicated by the time resource assignment of a prior SCI according to clause 8.3.1.1 of TS 38.212.

4 >

if sl-InterUE-CoordinationScheme1 enabling reception/transmission of preferred resource set and non-preferred resource set is configured by RRC and when the UE does not have own sensing result as specified in clause 8.1.4 of TS 38.214 and if a preferred resource set is received from a UE; and

4 >

if there are available resources left in the received preferred resource set for more transmission opportunities:

5 >

randomly select the time and frequency resources for one or more transmission opportunities from the available resources belonging to the received preferred resource set for a MAC PDU to be transmitted to the UE providing the preferred resource set, according to the amount of selected frequency resources, the selected number of HARQ retransmissions and the remaining PDB of SL data available in the logical channel(s) allowed on the carrier, and/or the latency requirement of the triggered SL-CSI reporting, and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available, by ensuring the minimum time gap between any two selected resources in case that PSFCH is configured for this pool of resources and that a retransmission resource can be indicated by the time resource assignment of a prior SCI according to clause 8.3.1.1 of TS 38.212.

4 >

5 >

randomly select the time and frequency resources for one transmission opportunity from the resources indicated by the physical layer as specified in clause 8.1.4 of TS 38.214, according to the amount of selected frequency resources, the remaining PDB of SL data available in the logical channel(s) allowed on the carrier, and/or the latency requirement of the triggered SL-CSI reporting and the latency requirement of the Sidelink Inter-UE Coordination Information transmission, and the remaining SL-PRS delay budget of the SL-PRS transmission(s), if available.

4 >

consider a transmission opportunity which comes first in time as the initial transmission opportunity and other transmission opportunities as the retransmission opportunities;

4 >

consider all the transmission opportunities as the selected sidelink grant.

3 >

else:

4 >

consider the set as the selected sidelink grant.

3 >

use the selected sidelink grant to determine PSCCH duration(s) and PSSCH duration(s) and the SL-PRS transmission occasion(s), if available, according to TS 38.214 if the selected resource pool is not SL-PRS Dedicated resource pool or to determine the PSCCH duration(s) and SL-PRS transmission occasion(s) if the selected resource pool is SL-PRS Dedicated resource pool according to TS 38.214.

1 >

if a selected sidelink grant is available for retransmission(s) of a MAC PDU which has been positively acknowledged as specified in clause 5.22.1.3.1a, except a positive acknowledgement to Multi-consecutive slots transmission (i.e., multiple TBs case) of the MAC PDU and there is remaining slot(s) for this MAC PDU:

2 >

clear the PSCCH duration(s) and PSSCH duration(s) corresponding to retransmission(s) of the MAC PDU from the selected sidelink grant.

If the UE is configured with IUC Scheme 1 (i.e., sl-InterUE-CoordinationScheme1 enabling reception/transmission of preferred resource set and non-preferred resource set is configured by RRC) and Co-ex (i.e., sl-NRPSSCH-EUTRA-ThresRSRP-List is configured by RRC) and the selected resource pool is not Dedicated SL-PRS resource pool and when SCS of NR SL is (pre-)configured as μ = 1, the MAC entity shall for each Sidelink process perform additional restriction of resource selection (on top of resource selection procedure for IUC scheme 1 above) as follow:

For initial transmission, randomly select first of NR SL slots overlapping with an LTE SL subframe for one transmission opportunity from the resources indicated in the resource selection procedure for IUC scheme 1 above;
For retransmission, randomly select the time and frequency resources in the second of NR SL slots overlapping with an LTE SL subframe to which the selected transmission resources belongs, or select the time and frequency resources in the first of NR SL slots overlapping with an LTE SL subframe for one transmission opportunity from the resources indicated in the resource selection procedure for IUC scheme 1 above.

For a selected sidelink grant, the minimum time gap between any two selected resources comprises:

For SL operation without shared spectrum channel access, a time gap between the end of the last symbol of a PSSCH transmission of the first resource and the start of the first symbol of the corresponding PSFCH reception determined by sl-MinTimeGapPSFCH and sl-PSFCH-Period for the pool of resources; and
For SL operation with shared spectrum channel access, the time gap between the end of the last symbol of a PSSCH transmission of the first resource and the start of the first symbol of the last corresponding PSFCH reception occasion determined by sl-MinTimeGapPSFCH, sl-NumPSFCH-Occasions and sl-PSFCH-Period for the pool of resources; and
a time required for PSFCH reception and processing plus sidelink retransmission preparation including multiplexing of necessary physical channels and any TX-RX/RX-TX switching time.

The MAC entity shall for each PSSCH duration not on SL-PRS Dedicated resource pool:

1 >

for each sidelink grant occurring in this PSSCH duration:

2 >

select a MCS table allowed in the pool of resource which is associated with the sidelink grant;

2 >

if the MAC entity has been configured with Sidelink resource allocation mode 1 or Sidelink resource allocation Scheme 1 for SL-PRS transmission on Shared SL-PRS resource pool:

3 >

select a MCS which is, if configured, within the range that is configured by RRC between sl-MinMCS-PSSCH and sl-MaxMCS-PSSCH associated with the selected MCS table included in sl-ConfigDedicatedNR;

3 >

set the resource reservation interval to 0ms.

2 >

else if the MAC entity has been configured with Sidelink resource allocation mode 2 or Sidelink resource allocation Scheme 2 for SL-PRS transmission on Shared SL-PRS resource pool:

3 >

select a MCS which is, if configured, within the range, if configured by RRC, between sl-MinMCS-PSSCH and sl-MaxMCS-PSSCH associated with the selected MCS table included in sl-PSSCH-TxConfigList and, if configured by RRC, overlapped between sl-MinMCS-PSSCH and sl-MaxMCS-PSSCH associated with the selected MCS table indicated in sl-CBR-PriorityTxConfigList for the highest priority of the sidelink logical channel(s) in the MAC PDU or pending SL-PRS transmission(s), if available, and the CBR measured by lower layers according to clause 5.1.27 of TS 38.215 if CBR measurement results are available or the corresponding sl-DefaultTxConfigIndex configured by RRC if CBR measurement results are not available or the corresponding sl-DefaultCBR-PartialSensing configured by RRC if partial sensing is selected and CBR measurement results are not available, or the corresponding sl-DefaultCBR-RandomSelection configured by RRC if random selection is selected and CBR measurement results are not available in case the sl-TxPoolExceptional is not used;

3 >

if the MAC entity decides not to use the selected sidelink grant for the next PSSCH duration corresponding to an initial transmission opportunity:

4 >

set the resource reservation interval to 0ms.

3 >

else:

4 >

set the resource reservation interval to the selected value.

2 >

if the configured sidelink grant has been activated and this PSSCH duration corresponds to the first PSSCH transmission opportunity within this sl-PeriodCG of the configured sidelink grant:

3 >

set the HARQ Process ID to the HARQ Process ID associated with this PSSCH duration and, if available, all subsequent PSSCH duration(s) occuring in this sl-PeriodCG for the configured sidelink grant;

3 >

determine that this PSSCH duration is used for initial transmission;

3 >

flush the HARQ buffer of Sidelink process associated with the HARQ Process ID.

2 >

deliver the sidelink grant, the selected MCS, and the associated HARQ information to the Sidelink HARQ Entity for this PSSCH duration.

The MAC entity shall for each PSCCH duration on SL-PRS Dedicated resource pool:

1 >

if the MAC entity is not configured with multiple SL-PRS transmissions with Sidelink resource allocation scheme 2; or

1 >

if the MAC entity is configured with Sidelink resource allocation scheme 1:

2 >

set the resource reservation period to 0.

1 >

else if the MAC entity is configured with multiple SL-PRS transmission with Sidelink resource allocation scheme 2:

2 >

set the resource reservation period to the selected value.

1 >

if the configured sidelink grant has been activated and this PSSCH duration corresponds to the first PSSCH transmission opportunity within this sl-PeriodCG of the configured sidelink grant:

2 >

set the SL-PRS Process ID to the SL-PRS Process ID associated with this PSSCH duration and, if available, all subsequent SL-PRS transmission occasion(s) occuring in this sl-PeriodCG for the configured sidelink grant;

2 >

determine that this SL-PRS transmission occasion is used for initial transmission.

1 >

process the sidelink grant according to clause 5.22.1.3.4 with the corresponding SL-PRS transmission information.

For configured sidelink grants not on SL-PRS Dedicated resource pool, the HARQ Process ID associated with the first slot of an SL transmission is derived from the following equation:

HARQ Process ID = [floor(CURRENT_slot / PeriodicitySL)] modulo sl-NrOfHARQ-Processes + sl-HARQ-ProcID-offset

For configured sidelink grant on SL-PRS Dedicated resource pool, the SL-PRS Process ID associated with the first slot of an SL transmission is derived from the following equation:

SL-PRS Process ID = [floor(CURRENT_slot / PeriodicitySL)] modulo [nrOfSL-PRSProc]

where CURRENT_slot refers to current logical slot in the associated resource pool, and PeriodicitySL is defined in clause 5.8.3.

5.22.1.2 TX resource (re-)selection check p. 166

If the TX resource (re-)selection check procedure is triggered on the selected pool of resources for a Sidelink process according to clause 5.22.1.1, the MAC entity shall for the Sidelink process:

1 >

if PSCCH duration(s) and 2nd stage SCI on PSSCH for all transmissions of a MAC PDU of any selected sidelink grant(s) are not in SL DRX Active time as specified in clause 5.28.3 of the destination that has data to be sent; or

1 >

if SL_RESOURCE_RESELECTION_COUNTER = 0 and when SL_RESOURCE_RESELECTION_COUNTER was equal to 1 the MAC entity randomly selected, with equal probability, a value in the interval [0, 1] which is above the probability configured by RRC in sl-ProbResourceKeep; or

1 >

if the pool of resources is configured or reconfigured by RRC; or

1 >

if there is no selected sidelink grant on the selected pool of resources; or

1 >

if neither transmission nor retransmission has been performed by the MAC entity on any resource indicated in the selected sidelink grant during the last second; or

1 >

if sl-ReselectAfter is configured and the number of consecutive unused transmission opportunities on resources indicated in the selected sidelink grant, which is incremented by 1 when none of the resources of the selected sidelink grant within a resource reservation interval is used, is equal to sl-ReselectAfter; or

1 >

if the selected sidelink grant cannot accommodate a RLC SDU by using the maximum allowed MCS configured by RRC in sl-MaxMCS-PSSCH associated with the selected MCS table and the UE selects not to segment the RLC SDU; or

1 >

if transmission(s) with the selected sidelink grant cannot fulfil the remaining PDB of the data in a logical or the remaining SL-PRS delay budget for SL-PRS transmission, if available channel, and the MAC entity selects not to perform transmission(s) corresponding to a single MAC PDU or SL-PRS transmission; or

1 >

if Sidelink consistent LBT failure is detected as specified in clause 5.31.2 in some RB set(s) of the selected resource pool that spans multiple RB sets for the logical channel, if single carrier frequency is configured; or

1 >

if a MAC PDU is not transmitted (i.e. initial transmission or retransmission) in any of the resources for this MAC PDU that are associated with the sidelink process for Multi-consecutive slots transmission due to the Sidelink LBT failure:

2 >

if multiple carrier frequencies are configured:

3 >

trigger the TX carrier (re-)selection procedure as specified in clause 5.22.1.11.

2 >

clear the selected sidelink grant associated to the Sidelink process, if available;

2 >

trigger the TX resource (re-)selection.

5.22.1.2a Re-evaluation and Pre-emption p. 167

A resource(s) of the selected sidelink grant for a MAC PDU to transmit from multiplexing and assembly entity or for a SL-PRS transmission is re-evaluated by physical layer at T3 before the slot where the SCI indicating the resource(s) is signalled at first time as specified in clause 8.1.4 of TS 38.214.

A resource(s) of the selected sidelink grant which has been indicated by a prior SCI for a MAC PDU to transmit from multiplexing and assembly entity or for a SL-PRS transmission could be checked for pre-emption by physical layer at T₃ before the slot where the resource(s) is located as specified in clause 8.1.4 of TS 38.214.

If the MAC entity has been configured with Sidelink resource allocation mode 2 or Sidelink resource allocation scheme 2 to transmit using pool(s) of resources in a carrier as indicated in TS 38.331 or TS 36.331 based on sensing or random selection the MAC entity shall for each Sidelink process or for each SL-PRS transmission:

1 >

if a resource(s) of the selected sidelink grant which has not been identified by a prior SCI is indicated for re-evaluation by the physical layer as specified in clause 8.1.4 of TS 38.214;

2 >

remove the resource(s) from the selected sidelink grant associated to the Sidelink process or SL-PRS transmission;

2 >

if the selected resource pool is not SL-PRS Dedicated resource pool:

3 >

randomly select the time and frequency resource from the resources indicated by the physical layer as specified in clause 8.1.4 of TS 38.214 for either the removed resource or the dropped resource, according to the amount of selected frequency resources, the selected number of HARQ retransmissions and the remaining PDB of either SL data available in the logical channel(s), and the remaining SL-PRS delay budget for SL-PRS transmission, if available, by ensuring the minimum time gap between any two selected resources of the selected sidelink grant in case that PSFCH is configured for this pool of resources, and that a resource can be indicated by the time resource assignment of an SCI for a retransmission according to clause 8.3.1.1 of TS 38.212;

2 >

else if the selected resource pool is SL-PRS Dedicated resource pool:

3 >

randomly select the time and frequency resource from the resources indicated by the physical layer as specified in clause 8.2.4 of TS 38.214 for either the removed resource or the dropped resource, according to the selected number of SL-PRS retransmissions and the remaining SL-PRS delay budget for SL-PRS transmission and that a resource can be indicated by the time resource assignment of an SCI for a retransmission according to clause 8.3.1.2 of TS 38.212.

2 >

replace the removed or dropped resource(s) by the selected resource(s) for the selected sidelink grant.

1 >

if any resource(s) of the selected sidelink grant which has been indicated by a prior SCI is indicated for pre-emption by the physical layer as specified in clause 8.1.4 of TS 38.214:

2 >

remove the resource(s) from the selected sidelink grant associated to the Sidelink process;

2 >

if one or multiple SL DRX is configured:

3 >

if the selected resource pool is not SL-PRS dedicated resource pool:

4 >

randomly select the time and frequency resource from the resources later than the resources for either the removed resource or the dropped resource indicated by a prior SCI, from the resource indicated by the physical layer as specified in clause 8.1.4 of TS 38.214 which occur within the SL DRX active time as specified in clause 5.28.3 of the destination UE selected for indicating to the physical layer the SL DRX active time above, according to the amount of selected frequency resources, the selected number of HARQ retransmissions and the remaining PDB of either SL data available in the logical channel(s) by ensuring the minimum time gap between any two selected resources of the selected sidelink grant in case that PSFCH is configured for this pool of resources, and the remaining SL-PRS delay budget for SL-PRS transmission, if available, and that a resource can be indicated by the time resource assignment of an SCI for a retransmission according to clause 8.3.1.1 of TS 38.212.

2 >

else:

3 >

if the selected resource pool is not SL-PRS Dedicated resource pool:

4 >

randomly select the time and frequency resource from the resources indicated by the physical layer as specified in clause 8.1.4 of TS 38.214 for either the removed resource or the dropped resource, according to the amount of selected frequency resources, the selected number of HARQ retransmissions and the remaining PDB of either SL data available in the logical channel(s) by ensuring the minimum time gap between any two selected resources of the selected sidelink grant in case that PSFCH is configured for this pool of resources, and the remaining SL-PRS delay budget for SL-PRS transmission, if available, and that a resource can be indicated by the time resource assignment of an SCI for a retransmission according to clause 8.3.1.1 of TS 38.212.

3 >

else if the selected resource pool is SL-PRS Dedicated resource pool:

4 >

2 >

replace the removed or dropped resource(s) by the selected resource(s) for the selected sidelink grant.

5.22.1.2b Re-selection for using a received resource conflict indication |R17| p. 169

If the MAC entity has been configured with Sidelink resource allocation mode 2 or Sidelink resource allocation scheme 2 to transmit using pool(s) of resources in a carrier as indicated in TS 38.331 based on full sensing, or partial sensing or random selection or any combination(s), the MAC entity shall for each Sidelink process:

1 >

if sl-interUECoordinationScheme2 enabling reception/transmission of a resource conflict indication is configured by RRC; and

1 >

if the next resource of the selected sidelink grant which has been indicated by a prior SCI is overlapped with conflict resource(s) indicated by the physical layer as specified in clause 16.3.1 of TS 38.213:

2 >

remove the resource from the selected sidelink grant associated to the Sidelink process;

2 >

if sl-NRPSSCH-EUTRA-ThresRSRP-List is configured by the RRC:

3 >

when SCS of NR SL is (pre-)configured as μ = 0:

4 >

randomly select the time and frequency resource from the resources indicated by the physical layer as specified in clause 8.1.4 of TS 38.214 excluding the conflict resource(s) for the removed resource, according to the amount of selected frequency resources, the selected number of HARQ retransmissions and the remaining PDB of either SL data available in the logical channel(s), and the remaining SL-PRS delay budget for SL-PRS transmission, if available, by ensuring the minimum time gap between any two selected resources of the selected sidelink grant in case that PSFCH is configured for this pool of resources, and that a resource can be indicated by the time resource assignment of an SCI for a retransmission according to clause 8.3.1.1 of TS 38.212;

3 >

when SCS of NR SL is (pre-)configured as μ = 1:

4 >

randomly select the time and frequency resources in the second of NR SL slots overlapping with an LTE SL subframe to which the selected transmission resources belongs, or select the time and frequency resources in the first of NR SL slots overlapping with an LTE SL subframe for one transmission opportunity from the available resources indicated by the physical layer as specified in clause 8.1.4 of TS 38.214 excluding the conflict resource(s) for the removed resource, according to the amount of selected frequency resources, the selected number of HARQ retransmissions and the remaining PDB of either SL data available in the logical channel(s), and the remaining SL-PRS delay budget for SL-PRS transmission, if available, by ensuring the minimum time gap between any two selected resources of the selected sidelink grant in case that PSFCH is configured for this pool of resources, and that a resource can be indicated by the time resource assignment of an SCI for a retransmission according to clause 8.3.1.1 of TS 38.212.

2 >

else:

3 >

2 >

replace the removed resource by the selected resource for the selected sidelink grant.

5.22.1.2c Resource re-selection from SL LBT Failure indication |R18| p. 170

If the MAC entity has been configured with Sidelink resource allocation mode 2 to transmit using pool(s) of resources in a carrier as indicated in TS 38.331 based on sensing or random selection the MAC entity shall for each Sidelink process:

1 >

if SL LBT failure indication is received from lower layers:

2 >

for the resource(s) where SL LBT failure is detected from the selected sidelink grant associated to the Sidelink process:

3 >

if transmission based on random selection is configured by upper layers:

4 >

randomly select the time and frequency resources for one transmission opportunity from the resource pool excluding all RB sets for which Sidelink consistent LBT failures were detected and not cancelled, if configured according to the amount of selected frequency resources, the selected number of HARQ retransmissions and the remaining PDB of SL data available in the logical channel(s) by ensuring the minimum time gap between any two selected resources of the selected sidelink grant in case that PSFCH is configured for this pool of resources.

3 >

else:

4 >

randomly select the time and frequency resources for one transmission opportunity from the resources indicated by the physical layer as specified in clause 8.1.4 of TS 38.214, according to the amount of selected frequency resources, the selected number of HARQ retransmissions and the remaining PDB of SL data available in the logical channel(s) by ensuring the minimum time gap between any two selected resources of the selected sidelink grant in case that PSFCH is configured for this pool of resources.

5.22.1.3 Sidelink HARQ operation and SL-PRS transmission p. 170

5.22.1.3.1 Sidelink HARQ Entity p. 170

The MAC entity is configured by upper layers to transmit using pool(s) of resources on one or more carriers as indicated in clause 5.8.8 of TS 38.331. For each carrier, the MAC entity includes at most one Sidelink HARQ entity for transmission on SL-SCH, which maintains a number of parallel Sidelink processes.

The maximum number of transmitting Sidelink processes associated with the Sidelink HARQ Entity is 16. A sidelink process may be configured for transmissions of multiple MAC PDUs. For transmissions of multiple MAC PDUs with Sidelink resource allocation mode 2, the maximum number of transmitting Sidelink processes associated with the Sidelink HARQ Entity is 4.

A delivered sidelink grant and its associated Sidelink transmission information are associated with a Sidelink process. Each Sidelink process supports one TB.

For each sidelink grant, the Sidelink HARQ Entity shall:

1 >

if the MAC entity determines that the sidelink grant is used for initial transmission as specified in clause 5.22.1.1; or

1 >

if the sidelink grant is a configured sidelink grant and no MAC PDU has been obtained in an sl-PeriodCG of the configured sidelink grant; or

1 >

if the sidelink grant is a dynamic sidelink grant or selected sidelink grant and no MAC PDU has been obtained in the previous sidelink grant when PSCCH duration(s) and 2nd stage SCI on PSSCH of the previous sidelink grant is not in SL DRX Active time as specified in clause 5.28.3 of any destination that has data to be sent:

2 >

(re-)associate a Sidelink process to this grant, and for the associated Sidelink process:

2 >

if all PSCCH duration(s) and PSSCH duration(s) for initial transmission of a MAC PDU of the dynamic sidelink grant or the configured sidelink grant is not in SL DRX Active time as specified in clause 5.28.3 of the destination that has data to be sent:

3 >

ignore the sidelink grant.

2 >

else:

3 >

obtain the MAC PDU and SL-PRS, if any, to transmit from the Multiplexing and assembly entity, if any;

3 >

if a MAC PDU to transmit has been obtained:

4 >

if a HARQ Process ID has been set for the sidelink grant:

5 >

(re-)associate the HARQ Process ID corresponding to the sidelink grant to the Sidelink process.

4 >

determines Sidelink transmission information of the TB for the source and destination pair of the MAC PDU as follows:

5 >

set the Source Layer-1 ID to the 8 LSB of the Source Layer-2 ID of the MAC PDU;

5 >

set the Destination Layer-1 ID to the 16 LSB of the Destination Layer-2 ID of the MAC PDU;

5 >

(re-)associate the Sidelink process to a Sidelink process ID;

5 >

consider the NDI to have been toggled compared to the value of the previous transmission corresponding to the Sidelink identification information and the Sidelink process ID of the MAC PDU and set the NDI to the toggled value;

5 >

if the MAC PDU is for NR sidelink discovery:

6 >

set the cast type indicator to broadcast.

5 >

else:

6 >

if the MAC PDU includes only Sidelink MAC CE(s):

7 >

if the MAC PDU includes only Sidelink Inter-UE Coordination Information MAC CE indicating non-preferred resource set and triggered by a condition other than the explicit request:

8 >

set the cast type indicator to one of broadcast, groupcast and unicast.

7 >

else:

8 >

set the cast type indicator to unicast.

6 >

else:

7 >

set the cast type indicator to one of broadcast, groupcast and unicast as indicated by upper layers.

5 >

if HARQ feedback has been enabled for the MAC PDU according to clause 5.22.1.4.2;

6 >

set the HARQ feedback enabled/disabled indicator to enabled.

5 >

else:

6 >

set the HARQ feedback enabled/disabled indicator to disabled.

5 >

set the priority to the value of the highest priority of the logical channel(s), if any, and MAC CE(s), if included, in the MAC PDU and SL-PRS, if any;

NOTE 3A:

When determining Sidelink transmission information, the priority of the Sidelink Inter-UE Coordination Information MAC CE is the value configured in RRC parameters sl-PriorityCoordInfoCondition when triggered by a condition, or sl-PriorityCoordInfoExplicit when triggered by an explicit request. When determining Sidelink transmission information, the priority of the Sidelink Inter-UE Coordination Request MAC CE is the value configured in RRC parameter sl-PriorityRequest. When determining Sidelink transmission information, the priority of the Sidelink Inter-UE Coordination Information MAC CE is the value indicated in Priority field in the Sidelink Inter-UE Coordination Request MAC CE provided by the UE when triggered by an explicit request, if sl-PriorityCoordInfoExplicit-r17 is not configured. When determining Sidelink transmission information for performing sensing and candidate resource selections in PHY, the priority value of the Sidelink Inter-UE Coordination Information MAC CE triggered under a condition is up to UE implementation, if sl-PriorityCoordInfoCondition-r17 is not configured. When determining Sidelink transmission information for performing sensing and candidate resource selections in PHY, the priority value of Sidelink Inter-UE Coordination Request MAC CE is the same as that of a TB to be transmitted by the UE, if sl-PriorityRequest-r17 is not configured.

5 >

if HARQ feedback is enabled for groupcast:

6 >

if both a group size and a member ID are provided by upper layers and the group size is not greater than the number of candidate PSFCH resources in a slot associated with this sidelink grant:

7 >

select either positive-negative acknowledgement or negative-only acknowledgement.

6 >

else:

7 >

select negative-only acknowledgement.

6 >

if negative-only acknowledgement is selected, UE's location information is available, and sl-TransRange has been configured for a logical channel in the MAC PDU, and sl-ZoneConfig is configured as specified in TS 38.331:

7 >

set the communication range requirement to the value of the longest communication range of the logical channel(s) in the MAC PDU;

7 >

determine the value of sl-ZoneLength corresponding to the communication range requirement and set Zone_id to the value of Zone_id calculated using the determined value of sl-ZoneLength as specified in TS 38.331.

5 >

set the Redundancy version to the selected value.

5 >

if the upper layers triggers the SL-PRS transmission of the peer UE identified by the Destination layer-2 ID:

6 >

set the SL-PRS request to request.

5 >

set the SL-PRS resource ID, if SL-PRS is available, within Sidelink transmission information.

4 >

deliver the MAC PDU, the SL-PRS, if available, the sidelink grant and the Sidelink transmission information of the TB and/or the SL-PRS to the associated Sidelink process;

4 >

instruct the associated Sidelink process to trigger a new transmission.

3 >

else:

4 >

flush the HARQ buffer of the associated Sidelink process.

1 >

else (i.e. retransmission):

2 >

if the HARQ Process ID corresponding to the sidelink grant received on PDCCH, the configured sidelink grant or the selected sidelink grant is associated to a Sidelink process of which HARQ buffer is empty; or

2 >

if the HARQ Process ID corresponding to the sidelink grant received on PDCCH is not associated to any Sidelink process; or

2 >

if PSCCH duration(s) and PSSCH duration(s) for one or more retransmissions of a MAC PDU of the dynamic sidelink grant or the configured sidelink grant is not in SL DRX Active time as specified in clause 5.28.3 of the destination that has data to be sent:

3 >

ignore the sidelink grant.

2 >

else:

3 >

identify the Sidelink process associated with this grant, and for the associated Sidelink process:

4 >

set the SL-PRS resource ID, if SL-PRS is available, within Sidelink transmission information;

4 >

deliver the sidelink grant and the Sidelink transmission information of the MAC PDU and the SL-PRS, if available, to the associated Sidelink process;

4 >

instruct the associated Sidelink process to trigger a retransmission.

5.22.1.3.1a Sidelink process not associated with Dedicated SL-PRS resource pool p. 173

The Sidelink process is associated with a HARQ buffer.

New transmissions and retransmissions are performed on the resource indicated in the sidelink grant as specified in clause 5.22.1.1 and with the MCS selected as specified in clause 8.1.3.1 of TS 38.214 and clause 5.22.1.1.

If the Sidelink process is configured to perform transmissions of multiple MAC PDUs with Sidelink resource allocation mode 2, the process maintains a counter SL_RESOURCE_RESELECTION_COUNTER. For other configurations of the Sidelink process, this counter is not available.

Priority of a MAC PDU and SL-PRS, if available, is determined by the highest priority of the logical channel(s), MAC CE(s) in the MAC PDU or SL-PRS.

If the Sidelink HARQ Entity requests a new transmission, the Sidelink process shall:

1 >

store the MAC PDU in the associated HARQ buffer;

1 >

store the sidelink grant received from the Sidelink HARQ Entity;

1 >

generate a transmission as described below.

If the Sidelink HARQ Entity requests a retransmission, the Sidelink process shall:

1 >

store the sidelink grant received from the Sidelink HARQ Entity;

1 >

generate a transmission as described below.

To generate a transmission, the Sidelink process shall:

1 >

if there is no uplink transmission; or

1 >

if the MAC entity is able to simultaneously perform uplink transmission(s) and sidelink transmission at the time of the transmission; or

1 >

if the other MAC entity and the MAC entity are able to simultaneously perform uplink transmission(s) and sidelink transmission at the time of the transmission respectively; or

1 >

if there is a MAC PDU to be transmitted for this duration in uplink, except a MAC PDU obtained from the Msg3 buffer, the MSGA buffer, or prioritized as specified in clause 5.4.2.2, and the sidelink transmission is prioritized over uplink transmission:

2 >

instruct the physical layer to transmit SCI according to the stored sidelink grant with the associated Sidelink transmission information;

2 >

instruct the physical layer to generate a transmission according to the stored sidelink grant;

2 >

if HARQ feedback has been enabled for the MAC PDU according to clause 5.22.1.4.2:

3 >

instruct the physical layer to monitor PSFCH for the transmission and perform PSFCH reception as specified in clause 5.22.1.3.2.

2 >

if sl-PUCCH-Config is configured by RRC for the stored sidelink grant:

3 >

determine transmission of an acknowledgement on the PUCCH as specified in clause 5.22.1.3.2.

1 >

if this transmission corresponds to the last transmission of the MAC PDU and SL-PRS, if available:

2 >

decrement SL_RESOURCE_RESELECTION_COUNTER by 1, if available.

1 >

if sl-MaxTransNum corresponding to the highest priority of the logical channel(s) in the MAC PDU has been configured in sl-CG-MaxTransNumList for the sidelink grant by RRC and the number of transmissions of the MAC PDU has been reached to sl-MaxTransNum; or

1 >

if a positive acknowledgement to this transmission of the MAC PDU was received according to clause 5.22.1.3.2, except a positive acknowledgement to Multi-consecutive slots transmission (i.e., multiple TBs case) of the MAC PDU and there is remaining slot(s) for this MAC PDU; or

1 >

if negative-only acknowledgement was enabled in the SCI and no negative acknowledgement was received for this transmission of the MAC PDU according to clause 5.22.1.3.2:

2 >

flush the HARQ buffer of the associated Sidelink process.

The transmission of the MAC PDU or SL-PRS, if available, is prioritized over uplink transmission(s) of the MAC entity or the other MAC entity if the following conditions are met:

1 >

if the MAC entity is not able to perform this sidelink transmission simultaneously with all uplink transmission(s) at the time of the transmission, and

1 >

if none of the uplink transmission(s) is prioritized by upper layer according to TS 23.287, and

1 >

if none of the NR uplink MAC PDU(s) includes any MAC CE prioritized as described in clause 5.4.3.1.3, and

1 >

if ul-PrioritizationThres is configured and if the value of the highest priority of logical channel(s) of all the NR uplink transmission(s) is not lower than ul-PrioritizationThres, and

1 >

if sl-PrioritizationThres is configured and if the value of the highest priority of logical channel(s) or MAC CE(s) in the MAC PDU is lower than sl-PrioritizationThres.

5.22.1.3.2 PSFCH reception p. 175

The MAC entity shall for each PSSCH transmission:

1 >

if an acknowledgement corresponding to the PSSCH transmission in clause 5.22.1.3.1a is obtained from the physical layer:

2 >

deliver the acknowledgement to the corresponding Sidelink HARQ entity for the Sidelink process;

1 >

else:

2 >

deliver a negative acknowledgement to the corresponding Sidelink HARQ entity for the Sidelink process;

1 >

if the PSSCH transmission occurs for a pair of Source Layer-2 ID and Destination Layer-2 ID corresponding to a PC5-RRC connection which has been established by upper layers:

2 >

perform the HARQ-Based Sidelink RLF Detection procedure as specified in clause 5.22.1.3.3.

If sl-PUCCH-Config is configured by RRC, the MAC entity shall for a PUCCH transmission occasion:

1 >

if the timeAlignmentTimer, associated with the TAG containing the Serving Cell on which the HARQ feedback is to be transmitted, is stopped or expired, and the Serving Cell is not configured with two TAGs; or

1 >

if the Serving Cell on which the HARQ feedback is to be transmitted is configured with two TAGs and if the timeAlignmentTimer of the TAG, associated with the TCI state(s) used for transmitting the HARQ feedback, is stopped or expired:

2 >

not instruct the physical layer to generate acknowledgement(s) of the data in this TB.

1 >

else if all PSCCH duration(s) and PSSCH duration(s) for initial transmission of a MAC PDU of the dynamic sidelink grant or the configured sidelink grant is not in SL DRX Active time as specified in clause 5.28.3 of the destination that has data to be sent and the sidelink grant is ignored according to clause 5.22.1.3.1:

2 >

instruct the physical layer to signal a positive acknowledgement corresponding to the transmission on the PUCCH according to clause 16.5 of TS 38.213.

1 >

else if a MAC PDU has been obtained for a sidelink grant associated to the PUCCH transmission occasion in clause 5.22.1.3.1, the MAC entity shall:

2 >

if the most recent transmission of the MAC PDU was not prioritized as specified in clause 5.22.1.3.1a:

3 >

instruct the physical layer to signal a negative acknowledgement on the PUCCH according to clause 16.5 of TS 38.213.

2 >

else if HARQ feedback has been disabled for the MAC PDU and next retransmission(s) of the MAC PDU is not required:

3 >

instruct the physical layer to signal a positive acknowledgement corresponding to the transmission on the PUCCH according to clause 16.5 of TS 38.213.

2 >

else if HARQ feedback has been disabled for the MAC PDU, and no sidelink grant is available for next retransmission(s) of the MAC PDU (including immediately after all PSSCH duration(s) in an sl-PeriodCG for the sidelink grant, the number of transmissions of the MAC PDU has not reached sl-MaxTransNum corresponding to the highest priority of the logical channel(s) in the MAC PDU, if configured in sl-CG-MaxTransNumList for the sidelink grant by RRC), if any; or

2 >

else if PSCCH duration(s) and PSSCH duration(s) for one or more retransmissions of a MAC PDU of the dynamic sidelink grant or the configured sidelink grant is not in SL DRX Active time as specified in clause 5.28.3 of the destination that has data to be sent:

3 >

instruct the physical layer to signal a negative acknowledgement corresponding to the transmission on the PUCCH according to clause 16.5 of TS 38.213.

2 >

else:

3 >

instruct the physical layer to signal an acknowledgement corresponding to the transmission on the PUCCH according to clause 16.5 of TS 38.213

1 >

else:

2 >

instruct the physical layer to signal a positive acknowledgement on the PUCCH according to clause 16.5 of TS 38.213.

5.22.1.3.3 HARQ-based Sidelink RLF detection p. 176

For each carrier associated with a PC5-RRC connection, the HARQ-based Sidelink RLF detection procedure is used to detect Sidelink RLF based on a number of consecutive DTX on PSFCH reception occasions for a PC5-RRC connection.

RRC configures the following parameter to control HARQ-based Sidelink RLF detection:

sl-maxNumConsecutiveDTX.

The following UE variable is used for HARQ-based Sidelink RLF detection.

numConsecutiveDTX, which is maintained per carrier per PC5-RRC connection.

For each carrier associated with a PC5-RRC connection, the Sidelink HARQ Entity shall (re-)initialize numConsecutiveDTX to zero for each PC5-RRC connection which has been established by upper layers, if any, upon establishment of the PC5-RRC connection or (re)configuration of sl-maxNumConsecutiveDTX.

For each carrier associated with a PC5-RRC connection, the Sidelink HARQ Entity shall for each PSFCH reception occasion associated to the PSSCH transmission:

1 >

if PSFCH reception is absent on the PSFCH reception occasion:

2 >

increment numConsecutiveDTX by 1;

2 >

if more than one carrier selected as defined in clause 5.22.1.11 is considered as the carriers for HARQ-based Sidelink RLF detection:

3 >

if numConsecutiveDTX reaches sl-maxNumConsecutiveDTX for all carriers applied for HARQ-based Sidelink RLF detection:

4 >

indicate HARQ-based Sidelink RLF detection to upper layers (i.e., RRC layer and V2X layer).

3 >

else if numConsecutiveDTX reaches sl-maxNumConsecutiveDTX for a carrier applied for HARQ-based Sidelink RLF detection:

4 >

trigger the TX carrier (re-)selection procedure as specified in clause 5.22.1.11;

4 >

indicate HARQ-based Sidelink carrier failure to upper layers (i.e., RRC layer and V2X layer).

2 >

else:

3 >

if numConsecutiveDTX reaches sl-maxNumConsecutiveDTX:

4 >

indicate HARQ-based Sidelink RLF detection to upper layers.

1 >

else:

2 >

re-initialize numConsecutiveDTX to zero.

5.22.1.3.4 Processing of sidelink grant on Dedicated SL-PRS resource pool |R18| p. 177

For each sidelink grant, the MAC entity shall:

1 >

if the MAC entity determines that the sidelink grant is used for initial transmission as specified in clause 5.22.1.1; or

1 >

if the sidelink grant is a configured sidelink grant and no MAC PDU has been obtained in an sl-PeriodCG of the configured sidelink grant:

2 >

associate a Sidelink process to this sidelink grant;

2 >

set the Destination ID to the Destination layer-2 ID corresponding to the SL-PRS transmission;

2 >

if the length of the Source ID is configured to as 12 bit:

3 >

set the Source ID to the 12 LSB of the Source layer-2 ID corresponding to the SL-PRS transmission;

2 >

else if length of the Source ID is configured to as 24 bit:

3 >

set the Source ID to the Source layer-2 ID corresponding to the SL-PRS transmission;

2 >

set the cast type indicator to one of broadcast, groupcast and unicast as indiated by the upper layer;

2 >

set the SL-PRS priority as the value indicated by upper layer;

2 >

set the SL-PRS resource ID;

2 >

if the upper layer triggers SL-PRS transmission of the peer UE identified by the Destination layer-2 ID:

3 >

set the SL-PRS request to request;

2 >

deliver the SL-PRS transmission information to the Sidelink process;

2 >

instruct the associated Sidelink process to trigger a new transmission as defined in 5.22.1.3.5.

1 >

else (i.e., retransmission):

2 >

identify the Sidelink process associated with this grant;

2 >

if sl-PRS-MaxNumTransmissions is configured and the number of transmissions of the SL-PRS has not reached sl-PRS-MaxNumTransmissions:

3 >

set the SL-PRS resource ID;

3 >

deliver the SL-PRS transmission information to the Sidelink process;

3 >

instruct the associated Sidelink process to trigger a retransmission as defined in 5.22.1.3.5.

5.22.1.3.5 Sidelink process associated with Dedicated SL-PRS resource pool |R18| p. 177

If the Sidelink process is configured to perform transmissions of multiple SL-PRS with Sidelink resource allocation scheme 2, the process maintains a counter SL_RESOURCE_RESELECTION_COUNTER. For other configurations of the Sidelink process, this counter is not available.For each SL-PRS new transmission or retransmission, the MAC entity shall:

1 >

if there is no uplink transmission; or

1 >

if there is uplink transmission and the sidelink transmission is prioritized over uplink transmission:

2 >

instruct the physical layer to transmit SCI of the SL grant with the associated SL-PRS transmission information on SL-PRS Dedicated resource pool;

2 >

instruct the physical layer to generate the SL-PRS on SL-PRS Dedicated resource pool.

1 >

if this transmission corresponds to the last transmission of the SL-PRS transmission:

2 >

decrement SL_RESOURCE_RESELECTION_COUNTER by 1, if available.

The transmission of the SL-PRS is prioritized over uplink transmission(s) of the MAC entity or the other MAC entity if the following conditions are met:

1 >

if the MAC entity is not able to perform this sidelink transmission simultaneously with all uplink transmission(s) at the time of the transmission, and

1 >

if ul-PrioritizationThres is configured and if the value of the highest priority of logical channel(s) of all the NR uplink transmission(s) is not lower than ul-PrioritizationThres, and

1 >

if sl-PrioritizationThres is configured and if the value of SL-PRS priority is lower than sl-PrioritizationThres.