Content for TS 38.321 Word version: 18.0.0

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…

5.2 Maintenance of Uplink Time Alignment 5.2a Maintenance of UL Synchronization 5.3 DL-SCH data transfer 5.3.1 DL Assignment reception 5.3.2 HARQ operation 5.3.3 Disassembly and demultiplexing
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5.2 Maintenance of Uplink Time Alignment p. 49

RRC configures the following parameters for the maintenance of UL time alignment:

timeAlignmentTimer (per TAG) which controls how long the MAC entity considers the Serving Cells to the associated TAG to be uplink time aligned for the TAG;
inactivePosSRS-TimeAlignmentTimer which controls how long the MAC entity considers the Positioning SRS transmission in RRC_INACTIVE in clause 5.26 to be uplink time aligned;
cg-SDT-TimeAlignmentTimer which controls how long the MAC entity considers the uplink transmission for CG-SDT to be uplink time aligned;
srs-ValidityAreaTimeAlignmentTimer which controls how long the MAC entity considers Positioning SRS transmission in RRC_INACTIVE in clause 5.26 to be uplink time aligned when SRS positioning validity area is configured.

The MAC entity shall:

1 >

when a Timing Advance Command MAC CE is received, and if an NTA (as defined in TS 38.211) has been maintained with the indicated TAG:

2 >

apply the Timing Advance Command for the indicated TAG;

2 >

if there is ongoing Positioning SRS Transmission in RRC_INACTIVE as in clause 5.26:

3 >

if SRS positioning validity area is configured:

4 >

start or restart the srs-ValidityAreaTimeAlignmentTimer associated with the indicated TAG.

3 >

else:

4 >

start or restart the inactivePosSRS-TimeAlignmentTimer associated with the indicated TAG.

2 >

if CG-SDT procedure triggered as in clause 5.27 is ongoing:

3 >

start or restart the cg-SDT-TimeAlignmentTimer associated with the indicated TAG.

2 >

else:

3 >

start or restart the timeAlignmentTimer associated with the indicated TAG.

1 >

when a Timing Advance Command is received in a Random Access Response message for a Serving Cell configured with two TAGs or in a MSGB for an SpCell configured with two TAGs:

2 >

if the Random Access Preamble was not selected by the MAC entity among the contention-based Random Access Preamble:

3 >

apply the Timing Advance Command for the TAG indicated in the received Random Access Response message or MSGB;

3 >

start or restart the timeAlignmentTimer associated with TAG indicated in the received Random Access Response message or MSGB.

2 >

else if the timeAlignmentTimer associated with the TAG indicated in the received Random Access Response message or MSGB is not running:

3 >

apply the Timing Advance Command for this TAG;

3 >

start the timeAlignmentTimer associated with this TAG;

3 >

when the Contention Resolution is considered not successful as described in clause 5.1.5:

4 >

stop the timeAlignmentTimer associated with this TAG.

2 >

else:

3 >

ignore the received Timing Advance Command.

1 >

when a Timing Advance Command is received in a Random Access Response message for a Serving Cell not configured with two TAGs or in a MSGB for an SpCell not configured with two TAGs:

2 >

if the Random Access Preamble was not selected by the MAC entity among the contention-based Random Access Preamble:

3 >

apply the Timing Advance Command for this TAG;

3 >

start or restart the timeAlignmentTimer associated with this TAG.

2 >

else if the timeAlignmentTimer associated with this TAG is not running:

3 >

apply the Timing Advance Command for this TAG;

3 >

start the timeAlignmentTimer associated with this TAG;

3 >

when the Contention Resolution is considered not successful as described in clause 5.1.5; or

3 >

when the Contention Resolution is considered successful for SI request as described in clause 5.1.5, after transmitting HARQ feedback for MAC PDU including UE Contention Resolution Identity MAC CE:

4 >

stop timeAlignmentTimer associated with this TAG.

3 >

when the Contention Resolution is considered not successful as described in clause 5.1.5:

4 >

if CG-SDT procedure triggered as in clause 5.27 is ongoing:

5 >

set the NTA value to the value before applying the received Timing Advance Command as in TS 38.211.

3 >

when the Contention Resolution is considered successful for Random Access procedure while the CG-SDT procedure is ongoing:

4 >

stop timeAlignmentTimer associated with this TAG;

4 >

start or restart the cg-SDT-TimeAlignmentTimer associated with this TAG.

3 >

when the Contention Resolution is considered successful for Random Access procedure while SRS transmission in RRC_INACTIVE is ongoing:

4 >

if SRS positioning validity area is configured:

5 >

start or restart the srs-ValidityAreaTimeAlignmentTimer associated with the indicated TAG.

4 >

else:

5 >

start or restart the inactivePosSRS-TimeAlignmentTimer associated with this TAG.

2 >

else:

3 >

ignore the received Timing Advance Command.

1 >

when an Absolute Timing Advance Command is received in response to a MSGA transmission including C-RNTI MAC CE, as specified in clause 5.1.4a, for an SpCell configured with two TAGs:

2 >

apply the Timing Advance Command for the PTAG indicated in the Absolute Timing Advance Command MAC CE;

2 >

start or restart the timeAlignmentTimer associated with this PTAG.

1 >

when an Absolute Timing Advance Command is received in response to a MSGA transmission including C-RNTI MAC CE, as specified in clause 5.1.4a, for an SpCell not configured with two TAGs:

2 >

apply the Timing Advance Command for PTAG;

2 >

if there is ongoing Positioning SRS Transmission in RRC_INACTIVE as in clause 5.26:

3 >

if SRS positioning validity area is configured:

4 >

start or restart the srs-ValidityAreaTimeAlignmentTimer associated with the indicated TAG.

3 >

else:

4 >

start or restart the inactivePosSRS-TimeAlignmentTimer associated with the indicated TAG.

2 >

if CG-SDT procedure is ongoing:

3 >

start or restart the cg-SDT-TimeAlignmentTimer associated with PTAG.

2 >

else:

3 >

start or restart the timeAlignmentTimer associated with PTAG.

1 >

when the MAC entity is configured with rach-LessHO:

2 >

set the NTA value (as defined in TS 38.211) to the value indicated by targetNTA in rach-LessHO for PTAG;

2 >

start the timeAlignmentTimer associated with PTAG.

1 >

when the indication is received from upper layer for stopping the inactivePosSRS-TimeAlignmentTimer:

2 >

stop the inactivePosSRS-TimeAlignmentTimer.

1 >

when the indication is received from upper layer for starting the inactivePosSRS-TimeAlignmentTimer:

2 >

start or restart the inactivePosSRS-TimeAlignmentTimer.

1 >

when instruction from the upper layer has been received for starting the cg-SDT-TimeAlignmentTimer:

2 >

start the cg-SDT-TimeAlignmentTimer.

1 >

when instruction from the upper layer has been received for stopping the cg-SDT-TimeAlignmentTimer:

2 >

consider the cg-SDT-TimeAlignmentTimer as expired.

1 >

when the indication is received from upper layer for starting the srs-ValidityArea-TimerAlignmentTimer:

2 >

start or restart the srs-ValidityArea-TimerAlignmentTimer.

1 >

when the indication is received from upper layer for stopping the srs-ValidityArea-TimerAlignmentTimer:

2 >

stop the srs-ValidityArea-TimerAlignmentTimer.

1 >

when instruction from the upper layer has been received for starting the TimeAlignmentTimer associated with PTAG:

2 >

start the TimeAlignmentTimer associated with PTAG.

1 >

when an LTM Cell Switch Command MAC CE including a Timing Advance Command is received:

2 >

apply the Timing Advance Command for the PTAG;

2 >

start or restart the timeAlignmentTimer associated with the PTAG.

1 >

when an LTM Cell Switch Command MAC CE is received and the UE has successfully measured the Timing Advance as in clause 5.18.35:

2 >

apply the measured Timing Advance for the PTAG;

2 >

start or restart the timeAlignmentTimer associated with the PTAG.

1 >

when a timeAlignmentTimer expires:

2 >

if the timeAlignmentTimer is associated with a PTAG and the SpCell is not configured with two PTAGs; or

2 >

if the timeAlignmentTimer is associated with a PTAG, the SpCell is configured with two PTAGs, and the timeAlignmentTimer associated with the other PTAG is not running:

3 >

flush all HARQ buffers for all Serving Cells;

3 >

notify RRC to release PUCCH for all Serving Cells, if configured;

3 >

notify RRC to release SRS for all Serving Cells, if configured;

3 >

clear any configured downlink assignments and configured uplink grants;

3 >

clear any PUSCH resource for semi-persistent CSI reporting;

3 >

consider all running timeAlignmentTimers as expired;

3 >

maintain NTA (defined in TS 38.211) of all TAGs.

2 >

else if the timeAlignmentTimer is associated with a TAG for an SCell, then for all SCells configured with only this TAG; or

2 >

if the timeAlignmentTimer is associated with a TAG for an SCell, and if the SCell is configured with two TAGs and the timeAlignmentTimer associated with the other TAG is not running, then for all such SCells:

3 >

flush all HARQ buffers;

3 >

notify RRC to release PUCCH, if configured;

3 >

notify RRC to release SRS, if configured;

3 >

clear any configured downlink assignments and configured uplink grants;

3 >

clear any PUSCH resource for semi-persistent CSI reporting;

3 >

maintain NTA (defined in TS 38.211) of this TAG.

2 >

else if the timeAlignmentTimer is associated with a TAG for a Serving Cell configured with two TAGs, and if the timeAlignmentTimer associated with the other TAG is running, then for all such Serving Cells:

3 >

clear any configured downlink assignment, if the activated TCI state(s) for all PUCCH resources configured for the configured downlink assignment is associated with the TAG of the expired timeAlignmentTimer;

3 >

clear any configured uplink grant, if the activated TCI state(s) for the configured uplink grant is associated with the TAG of the expired timeAlignmentTimer;

3 >

clear any PUSCH resource for semi-persistent CSI reporting, if the activated TCI state(s) for the PUSCH resource is associated with the TAG of the expired timeAlignmentTimer;

3 >

maintain NTA (defined in TS 38.211) of this TAG.

1 >

when the inactivePosSRS-TimeAlignmentTimer expires:

2 >

notify RRC to release Positioning SRS for RRC_INACTIVE configuration(s).

1 >

when the cg-SDT-TimeAlignmentTimer expires:

2 >

clear any configured uplink grants;

2 >

if a PDCCH addressed to the MAC entity's C-RNTI after initial transmission for the CG-SDT with CCCH message has not been received:

3 >

consider ongoing CG-SDT procedure as terminated;

3 >

indicate the expiry of cg-SDT-TimeAlignmentTimer to the upper layer.

2 >

flush all HARQ buffers;

2 >

maintain NTA (defined in TS 38.211) of this TAG.

When the MAC entity stops uplink transmissions for an SCell not configured with two TAGs due to the fact that the maximum uplink transmission timing difference between TAGs of the MAC entity or the maximum uplink transmission timing difference between TAGs of any MAC entity of the UE is exceeded, the MAC entity considers the timeAlignmentTimer associated with the SCell as expired.

When the MAC entity stops uplink transmissions associated to a STAG for an SCell configured with two TAGs due to the fact that the maximum uplink transmission timing difference between TAGs of the MAC entity or the maximum uplink transmission timing difference between TAGs of any MAC entity of the UE is exceeded, the MAC entity considers the timeAlignmentTimer associated with the STAG as expired.

The MAC entity shall not perform any uplink transmission on a Serving Cell except the Random Access Preamble and MSGA transmission when the timeAlignmentTimer(s) associated with all TAG(s) to which this Serving Cell belongs is not running, CG-SDT procedure is not ongoing and SRS transmission in RRC_INACTIVE as in clause 5.26 is not on-going. Furthermore, when the timeAlignmentTimer(s) associated with all PTAG(s) is not running, CG-SDT procedure is not ongoing and SRS transmission in RRC_INACTIVE as in clause 5.26 is not ongoing, the MAC entity shall not perform any uplink transmission on any Serving Cell except the Random Access Preamble and MSGA transmission on the SpCell. The MAC entity shall not perform any uplink transmission except the Random Access Preamble and MSGA transmission when the cg-SDT-TimeAlignmentTimer is not running during the ongoing CG-SDT procedure as triggered in clause 5.27 and the inactivePosSRS-TimeAlignmentTimer or srs-ValidityAreaTimeAlignmentTimer is not running. The MAC entity shall not perform any uplink transmission except the Random Access Preamble and MSGA transmission on a Serving Cell using TCI state(s) associated with a TAG for which the timeAlignmentTimer is not running.

5.2a Maintenance of UL Synchronization |R17| p. 53

The MAC entity shall for each Serving Cell:

1 >

if an indication of uplink synchronization has been received from upper layers (see clauses 5.2.2.6 and 5.7.19 of TS 38.331):

2 >

if indication of uplink synchronization is received after indication of uplink synchronization loss due to satellite switch with re-synchronization (see clause 5.7.19 of TS 38.331):

3 >

set NTA value (as defined in TS 38.211) to zero for PTAG;

3 >

indicate to lower layers a Differential Koffset with value zero.

2 >

allow uplink transmission on the Serving Cell.

1 >

if an indication of uplink synchronization loss or uplink synchronization loss due to satellite switch with re-synchronization is received from upper layers (see clause 5.2.2.6 and 5.7.19 of TS 38.331):

2 >

flush all HARQ buffers;

2 >

not perform any uplink transmission on the Serving Cell.

5.3 DL-SCH data transfer p. 53

5.3.1 DL Assignment reception p. 53

Downlink assignments received on the PDCCH both indicate that there is a transmission on a DL-SCH for a particular MAC entity and provide the relevant HARQ information.

When the MAC entity has a C-RNTI, Temporary C-RNTI, CS-RNTI, G-RNTI or G-CS-RNTI, the MAC entity shall for each PDCCH occasion during which it monitors PDCCH and for each Serving Cell:

1 >

if a downlink assignment for this PDCCH occasion and this Serving Cell has been received on the PDCCH for the MAC entity's C-RNTI, or Temporary C-RNTI, or G-RNTI configured for multicast MTCH:

2 >

if this is the first downlink assignment for this Temporary C-RNTI:

3 >

consider the NDI to have been toggled.

2 >

if the downlink assignment is for the MAC entity's C-RNTI, and if the previous downlink assignment indicated to the HARQ entity of the same HARQ process was either a downlink assignment received for the MAC entity's CS-RNTI or G-CS-RNTI, or a configured downlink assignment for unicast or MBS multicast; or

2 >

if the downlink assignment is for the MAC entity's G-RNTI configured for multicast MTCH, and if the previous downlink assignment indicated to the HARQ entity of the same HARQ process was either a downlink assignment received for the MAC entity's CS-RNTI or G-CS-RNTI, or other G-RNTI, or C-RNTI, or a configured downlink assignment for unicast or MBS multicast:

3 >

consider the NDI to have been toggled regardless of the value of the NDI.

2 >

stop the cg-SDT-RetransmissionTimer, if it is running, for the corresponding HARQ process for initial transmission with CCCH message;

2 >

stop the cg-RACH-less-RetransmissionTimer, if it is running, for the corresponding HARQ process for initial transmission of RACH-less handover;

2 >

stop the cg-LTM-RetransmissionTimer, if it is running, for the corresponding HARQ process for the first PUSCH transmission at LTM cell switch;

2 >

stop the configuredGrantTimer, if it is running, for the corresponding HARQ process for initial transmission with CCCH message;

2 >

if there is an ongoing RACH-less handover procedure; and

2 >

if the downlink assignment has been received on the PDCCH for the MAC entity's C-RNTI after the first PUSCH transmission to the Serving Cell; and

2 >

if the downlink assignment is for a new transmission:

3 >

indicate to upper layers the successful completion of RACH-less handover.

2 >

indicate the presence of a downlink assignment and deliver the associated HARQ information to the HARQ entity.

2 >

if there is an ongoing RACH-less LTM cell switch; and

2 >

if the downlink assignment has been received on the PDCCH for the MAC entity's C-RNTI after the first PUSCH transmission to the Serving Cell; and

2 >

if the downlink assignment is for a new transmission:

3 >

consider the LTM cell switch to be successfully completed and indicate it to upper layers.

1 >

else if a downlink assignment for this PDCCH occasion has been received for this Serving Cell on the PDCCH for the MAC entity's CS-RNTI or G-CS-RNTI:

2 >

if the NDI in the received HARQ information is 1:

3 >

consider the NDI for the corresponding HARQ process not to have been toggled;

3 >

indicate the presence of a downlink assignment for this Serving Cell and deliver the associated HARQ information to the HARQ entity.

2 >

if the NDI in the received HARQ information is 0:

3 >

if PDCCH contents indicate SPS deactivation:

4 >

clear the configured downlink assignment for this Serving Cell (if any);

4 >

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

4 >

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 running:

5 >

indicate a positive acknowledgement for the SPS deactivation to the physical layer.

3 >

else if PDCCH content indicates SPS activation:

4 >

store the downlink assignment for this Serving Cell and the associated HARQ information as configured downlink assignment;

4 >

initialise or re-initialise the configured downlink assignment for this Serving Cell to start in the associated PDSCH duration and to recur according to rules in clause 5.8.1 or in clause 5.8.1a;

For each Serving Cell and each configured downlink assignment, if configured and activated, the MAC entity shall:

1 >

if the PDSCH duration of the configured downlink assignment does not overlap with the PDSCH duration of a downlink assignment received on the PDCCH for this Serving Cell:

2 >

instruct the physical layer to receive, in this PDSCH duration, transport block on the DL-SCH according to the configured downlink assignment and to deliver it to the HARQ entity;

2 >

set the HARQ Process ID to the HARQ Process ID associated with this PDSCH duration;

2 >

consider the NDI bit for the corresponding HARQ process to have been toggled;

2 >

indicate the presence of a configured downlink assignment and deliver the stored HARQ information to the HARQ entity.

For configured downlink assignments without harq-ProcID-Offset, the HARQ Process ID associated with the slot where the DL transmission starts is derived from the following equation:

HARQ Process ID = [floor (CURRENT_slot × 10 / (numberOfSlotsPerFrame × periodicity))]

modulo nrofHARQ-Processes

where CURRENT_slot = [(SFN × numberOfSlotsPerFrame) + slot number in the frame] and numberOfSlotsPerFrame refers to the number of consecutive slots per frame as specified in TS 38.211.

For configured downlink assignments with harq-ProcID-Offset, the HARQ Process ID associated with the slot where the DL transmission starts is derived from the following equation:

HARQ Process ID = [floor (CURRENT_slot × 10 / (numberOfSlotsPerFrame × periodicity))]

modulo nrofHARQ-Processes + harq-ProcID-Offset

where CURRENT_slot = [(SFN × numberOfSlotsPerFrame) + slot number in the frame] and numberOfSlotsPerFrame refers to the number of consecutive slots per frame as specified in TS 38.211.

When the MAC entity needs to read BCCH, the MAC entity may, based on the scheduling information from RRC:

1 >

if a downlink assignment for this PDCCH occasion has been received on the PDCCH for the SI-RNTI;

2 >

indicate a downlink assignment and redundancy version for the dedicated broadcast HARQ process to the HARQ entity.

When the MAC entity needs to read MCCH, the MAC entity may, based on the scheduling information from RRC:

1 >

if a downlink assignment for this PDCCH occasion has been received on the PDCCH for the MCCH-RNTI or Multicast MCCH-RNTI:

2 >

indicate a downlink assignment and redundancy version for the selected HARQ process to the HARQ entity.

When the MAC entity needs to read broadcast MTCH, the MAC entity may, based on the scheduling information from RRC and DCI:

1 >

if a downlink assignment for this PDCCH occasion has been received on the PDCCH for the G-RNTI configured for broadcast MTCH:

2 >

indicate the presence of a downlink assignment and deliver the associated HARQ information for the selected HARQ process to the HARQ entity.

5.3.2 HARQ operation p. 56

5.3.2.1 HARQ Entity p. 56

The MAC entity includes a HARQ entity for each Serving Cell, which maintains a number of parallel HARQ processes. Each HARQ process is associated with a HARQ process identifier. The HARQ entity directs HARQ information and associated TBs received on the DL-SCH to the corresponding HARQ processes (see clause 5.3.2.2).

The number of parallel DL HARQ processes per HARQ entity is specified in TS 38.214. The dedicated broadcast HARQ process is used for BCCH.

The HARQ process supports one TB when the physical layer is not configured for downlink spatial multiplexing. The HARQ process supports one or two TBs when the physical layer is configured for downlink spatial multiplexing.

When the MAC entity is configured with pdsch-AggregationFactor > 1, the parameter pdsch-AggregationFactor provides the number of transmissions of a TB within a bundle of the downlink assignment. Bundling operation relies on the HARQ entity for invoking the same HARQ process for each transmission that is part of the same bundle. After the initial transmission, pdsch-AggregationFactor - 1 HARQ retransmissions follow within a bundle.

The MAC entity shall:

1 >

if a downlink assignment has been indicated:

2 >

allocate the TB(s) received from the physical layer and the associated HARQ information to the HARQ process indicated by the associated HARQ information.

1 >

if a downlink assignment has been indicated for the broadcast HARQ process:

2 >

allocate the received TB to the broadcast HARQ process.

5.3.2.2 HARQ process p. 56

When a transmission takes place for the HARQ process, one or two (in case of downlink spatial multiplexing) TBs and the associated HARQ information are received from the HARQ entity.

For each received TB and associated HARQ information, the HARQ process shall:

1 >

if the NDI, when provided, has been toggled compared to the value of the previous received transmission corresponding to this TB; or

1 >

if the HARQ process is equal to the broadcast process, and this is the first received transmission for the TB according to the system information schedule indicated by RRC; or

1 >

if the HARQ process is associated with a transmission indicated with a MCCH-RNTI for MBS broadcast, and this is the first received transmission for the TB according to the broadcast MCCH schedule indicated by RRC; or

1 >

if the HARQ process is associated with a transmission indicated with a Multicast MCCH-RNTI for MBS multicast, and this is the first received transmission for the TB according to the multicast MCCH schedule indicated by RRC; or

1 >

if the HARQ process is associated with a transmission indicated with a G-RNTI for MBS broadcast, and this is the first received transmission for the TB according to the MTCH schedule indicated by RRC or according to the scheduling indicated by DCI as specified in TS 38.214; or

1 >

if this is the very first received transmission for this TB (i.e. there is no previous NDI for this TB):

2 >

consider this transmission to be a new transmission.

1 >

else:

2 >

consider this transmission to be a retransmission.

The MAC entity then shall:

1 >

if this is a new transmission:

2 >

attempt to decode the received data.

1 >

else if this is a retransmission:

2 >

if the data for this TB has not yet been successfully decoded:

3 >

instruct the physical layer to combine the received data with the data currently in the soft buffer for this TB and attempt to decode the combined data.

1 >

if the data which the MAC entity attempted to decode was successfully decoded for this TB; or

1 >

if the data for this TB was successfully decoded before:

2 >

if the HARQ process is equal to the broadcast process:

3 >

deliver the decoded MAC PDU to upper layers.

2 >

else if this is the first successful decoding of the data for this TB:

3 >

deliver the decoded MAC PDU to the disassembly and demultiplexing entity.

1 >

else:

2 >

instruct the physical layer to replace the data in the soft buffer for this TB with the data which the MAC entity attempted to decode.

1 >

if the HARQ process is associated with a transmission indicated with a Temporary C-RNTI and the Contention Resolution is not yet successful (see clause 5.1.5); or

1 >

if the HARQ process is associated with a transmission indicated with a MSGB-RNTI and the Random Access procedure is not yet successfully completed (see clause 5.1.4a); or

1 >

if the HARQ process is equal to the broadcast process; or

1 >

if the HARQ process is associated with a transmission indicated with a MCCH-RNTI or a G-RNTI for MBS broadcast; or

1 >

if the HARQ process is associated with a transmission indicated with a Multicast MCCH-RNTI for MBS multicast; or

1 >

if the HARQ process is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast and HARQ feedback is disabled for this G-RNTI or G-CS-RNTI or the corresponding G-CS-RNTI, as specified in clause 18 of TS 38.213; or

1 >

if the HARQ process is associated with a transmission indicated with a G-RNTI or a G-CS-RNTI or a configured downlink assignment for MBS multicast and NACK only HARQ feedback is used for this G-RNTI or G-CS-RNTI or the corresponding G-CS-RNTI and the data for this TB is successfully decoded and the transmission is not the first transmission of PDSCH where the configured downlink assignment was (re-)initialised; or

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, and if the cg-SDT-TimeAlignmentTimer, if configured, is not running; or

1 >

2 >

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

1 >

else if the HARQ process is configured with disabled HARQ feedback:

2 >

if harq-FeedbackEnablingforSPSactive is configured with value true and the transmission is the first transmission on the configured downlink assignment after activation of the configured downlink assignment:

3 >

instruct the physical layer to generate acknowledgement(s) of the data in this TB.

2 >

else:

3 >

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

1 >

else:

2 >

instruct the physical layer to generate acknowledgement(s) of the data in this TB.

The MAC entity shall ignore NDI received in all downlink assignments on PDCCH for its Temporary C-RNTI when determining if NDI on PDCCH for its C-RNTI has been toggled compared to the value in the previous transmission.

5.3.3 Disassembly and demultiplexing p. 58

The MAC entity shall disassemble and demultiplex a MAC PDU as defined in clauses 6.1.2 and 6.1.5a.

When a MAC entity receives a MAC PDU for MAC entity's G-RNTI or G-CS-RNTI, or by the configured downlink assignment for MBS multicast containing an LCID or eLCID which is not configured, the MAC entity shall at least:

1 >

discard the received subPDU.