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…

5.1.2 Random Access Resource selection 5.1.2a Random Access Resource selection for 2-step RA type 5.1.3 Random Access Preamble transmission 5.1.3a MSGA transmission 5.1.4 Random Access Response reception 5.1.4a MSGB reception and contention resolution for 2-step RA type 5.1.5 Contention Resolution 5.1.6 Completion of the Random Access procedure
...

5.1.2 Random Access Resource selection p. 31

If the selected RA_TYPE is set to 4-stepRA, the MAC entity shall:

1 >

if the Random Access procedure was initiated for SpCell beam failure recovery (as specified in clause 5.17); and

1 >

if the beamFailureRecoveryTimer (in clause 5.17) is either running or not configured; and

1 >

if the contention-free Random Access Resources for beam failure recovery request associated with any of the SSBs and/or CSI-RSs have been explicitly provided by RRC; and

1 >

if at least one of the SSBs with SS-RSRP above rsrp-ThresholdSSB amongst the SSBs in candidateBeamRSList or the CSI-RSs with CSI-RSRP above rsrp-ThresholdCSI-RS amongst the CSI-RSs in candidateBeamRSList is available:

2 >

select an SSB with SS-RSRP above rsrp-ThresholdSSB amongst the SSBs in candidateBeamRSList or a CSI-RS with CSI-RSRP above rsrp-ThresholdCSI-RS amongst the CSI-RSs in candidateBeamRSList;

2 >

if CSI-RS is selected, and there is no ra-PreambleIndex associated with the selected CSI-RS:

3 >

set the PREAMBLE_INDEX to a ra-PreambleIndex corresponding to the SSB in candidateBeamRSList which is quasi-colocated with the selected CSI-RS as specified in TS 38.214.

2 >

else:

3 >

set the PREAMBLE_INDEX to a ra-PreambleIndex corresponding to the selected SSB or CSI-RS from the set of Random Access Preambles for beam failure recovery request.

1 >

else if the ra-PreambleIndex has been explicitly provided by PDCCH; and

1 >

if the ra-PreambleIndex is not 0b000000:

2 >

set the PREAMBLE_INDEX to the signalled ra-PreambleIndex;

2 >

select the SSB signalled by PDCCH.

1 >

else if the ra-PreambleIndex has been explicitly provided by an LTM Cell Switch Command MAC CE:

2 >

set the PREAMBLE_INDEX to the indicated ra-PreambleIndex;

2 >

select the SSB signalled by the LTM Cell Switch Command MAC CE.

1 >

else if the contention-free Random Access Resources associated with SSBs have been explicitly provided in rach-ConfigDedicated and at least one SSB with SS-RSRP above rsrp-ThresholdSSB amongst the associated SSBs is available:

2 >

select an SSB with SS-RSRP above rsrp-ThresholdSSB amongst the associated SSBs;

2 >

set the PREAMBLE_INDEX to a ra-PreambleIndex corresponding to the selected SSB.

1 >

else if the contention-free Random Access Resources associated with CSI-RSs have been explicitly provided in rach-ConfigDedicated and at least one CSI-RS with CSI-RSRP above rsrp-ThresholdCSI-RS amongst the associated CSI-RSs is available:

2 >

select a CSI-RS with CSI-RSRP above rsrp-ThresholdCSI-RS amongst the associated CSI-RSs;

2 >

set the PREAMBLE_INDEX to a ra-PreambleIndex corresponding to the selected CSI-RS.

1 >

else if the Random Access procedure was initiated for SI request (as specified in TS 38.331); and

1 >

if the Random Access Resources for SI request have been explicitly provided by RRC:

2 >

if at least one of the SSBs with SS-RSRP above rsrp-ThresholdSSB is available:

3 >

select an SSB with SS-RSRP above rsrp-ThresholdSSB.

2 >

else:

3 >

select any SSB.

2 >

select a Random Access Preamble corresponding to the selected SSB, from the Random Access Preamble(s) determined according to ra-PreambleStartIndex as specified in TS 38.331;

2 >

set the PREAMBLE_INDEX to selected Random Access Preamble.

1 >

else (i.e. for the contention-based Random Access preamble selection):

2 >

if at least one of the SSBs with SS-RSRP above rsrp-ThresholdSSB is available:

3 >

select an SSB with SS-RSRP above rsrp-ThresholdSSB.

2 >

else:

3 >

select any SSB.

2 >

if the RA_TYPE is switched from 2-stepRA to 4-stepRA:

3 >

if a Random Access Preambles group was selected during the current Random Access procedure:

4 >

select the same group of Random Access Preambles as was selected for the 2-step RA type.

3 >

else:

4 >

if Random Access Preambles group B is configured; and

4 >

if the transport block size of the MSGA payload configured in the rach-ConfigDedicated corresponds to the transport block size of the MSGA payload associated with Random Access Preambles group B:

5 >

select the Random Access Preambles group B.

4 >

else:

5 >

select the Random Access Preambles group A.

2 >

else if Msg3 buffer is empty:

3 >

if Random Access Preambles group B is configured:

4 >

if the potential Msg3 size (UL data available for transmission plus MAC subheader(s) and, where required, MAC CEs) is greater than ra-Msg3SizeGroupA and the pathloss is less than PCMAX (of the Serving Cell performing the Random Access Procedure) - preambleReceivedTargetPower - msg3-DeltaPreamble - messagePowerOffsetGroupB; or

4 >

if the Random Access procedure was initiated for the CCCH logical channel and the CCCH SDU size plus MAC subheader is greater than ra-Msg3SizeGroupA:

5 >

select the Random Access Preambles group B.

4 >

else:

5 >

select the Random Access Preambles group A.

3 >

else:

4 >

select the Random Access Preambles group A.

2 >

else (i.e. Msg3 is being retransmitted):

3 >

select the same group of Random Access Preambles as was used for the Random Access Preamble transmission attempt corresponding to the first transmission of Msg3.

2 >

select a Random Access Preamble randomly with equal probability from the Random Access Preambles associated with the selected SSB and the selected Random Access Preambles group;

2 >

set the PREAMBLE_INDEX to the selected Random Access Preamble.

1 >

if the Random Access procedure was initiated for SI request (as specified in TS 38.331); and

1 >

if ra-AssociationPeriodIndex and si-RequestPeriod are configured:

2 >

determine the next available PRACH occasion from the PRACH occasions corresponding to the selected SSB in the association period given by ra-AssociationPeriodIndex in the si-RequestPeriod permitted by the restrictions given by the ra-ssb-OccasionMaskIndex if configured (the MAC entity shall select a PRACH occasion randomly with equal probability amongst the consecutive PRACH occasions according to clause 8.1 of TS 38.213 corresponding to the selected SSB).

1 >

else if an SSB is selected above:

2 >

if the set of Random Access resources associated with Msg1 repetition is selected for this Random Access procedure:

3 >

determine the next available set of PRACH occasions (as specified in TS 38.213) for the Msg1 repetition number applicable for this Random Access procedure corresponding to the selected SSB, permitted by the restrictions given by the ra-ssb-OccasionMaskIndex if configured, or ssb-SharedRO-MaskIndex if configured (the MAC entity shall select a set of PRACH occasions randomly with equal probability amongst the consecutive PRACH occasions according to clause 8.1 of TS 38.213 regardless the FR2 UL gap, corresponding to the selected SSB and selected Msg1 repetition number for this Random Access procedure; the MAC entity may take into account the possible occurrence of measurement gaps and MUSIM gaps when determining the next available set of PRACH occasions corresponding to the selected SSB).

2 >

else:

3 >

determine the next available PRACH occasion from the PRACH occasions corresponding to the selected SSB permitted by the restrictions given by the ra-ssb-OccasionMaskIndex if configured, or ssb-SharedRO-MaskIndex if configured, or indicated by PDCCH, or indicated by the LTM Cell Switch Command MAC CE (the MAC entity shall select a PRACH occasion randomly with equal probability amongst the consecutive PRACH occasions according to clause 8.1 of TS 38.213 regardless the FR2 UL gap, corresponding to the selected SSB; the MAC entity may take into account the possible occurrence of measurement gaps and MUSIM gaps when determining the next available PRACH occasion corresponding to the selected SSB).

1 >

else if a CSI-RS is selected above:

2 >

if there is no contention-free Random Access Resource associated with the selected CSI-RS:

3 >

determine the next available PRACH occasion from the PRACH occasions, permitted by the restrictions given by the ra-ssb-OccasionMaskIndex if configured, corresponding to the SSB in candidateBeamRSList which is quasi-colocated with the selected CSI-RS as specified in TS 38.214 (the MAC entity shall select a PRACH occasion randomly with equal probability amongst the consecutive PRACH occasions according to clause 8.1 of TS 38.213 regardless the FR2 UL gap, corresponding to the SSB which is quasi-colocated with the selected CSI-RS; the MAC entity may take into account the possible occurrence of measurement gaps and MUSIM gaps when determining the next available PRACH occasion corresponding to the SSB which is quasi-colocated with the selected CSI-RS).

2 >

else:

3 >

determine the next available PRACH occasion from the PRACH occasions in ra-OccasionList corresponding to the selected CSI-RS (the MAC entity shall select a PRACH occasion randomly with equal probability amongst the PRACH occasions occurring simultaneously but on different subcarriers regardless the FR2 UL gap, corresponding to the selected CSI-RS; the MAC entity may take into account the possible occurrence of measurement gaps and MUSIM gaps when determining the next available PRACH occasion corresponding to the selected CSI-RS).

1 >

perform the Random Access Preamble transmission procedure (see clause 5.1.3).

5.1.2a Random Access Resource selection for 2-step RA type |R16| p. 35

If the selected RA_TYPE is set to 2-stepRA, the MAC entity shall:

1 >

if the contention-free 2-step RA type Resources associated with SSBs have been explicitly provided in rach-ConfigDedicated and at least one SSB with SS-RSRP above msgA-RSRP-ThresholdSSB amongst the associated SSBs is available:

2 >

select an SSB with SS-RSRP above msgA-RSRP-ThresholdSSB amongst the associated SSBs;

2 >

set the PREAMBLE_INDEX to a ra-PreambleIndex corresponding to the selected SSB.

1 >

else (i.e. for the contention-based Random Access Preamble selection):

2 >

if at least one of the SSBs with SS-RSRP above msgA-RSRP-ThresholdSSB is available:

3 >

select an SSB with SS-RSRP above msgA-RSRP-ThresholdSSB.

2 >

else:

3 >

select any SSB.

2 >

if contention-free Random Access Resources for 2-step RA type have not been configured and if Random Access Preambles group has not yet been selected during the current Random Access procedure:

3 >

if Random Access Preambles group B for 2-step RA type is configured:

4 >

if the potential MSGA payload size (UL data available for transmission plus MAC subheader and, where required, MAC CEs) is greater than the ra-MsgA-SizeGroupA and the pathloss is less than PCMAX (of the Serving Cell performing the Random Access Procedure) - msgA-PreambleReceivedTargetPower - msgA-DeltaPreamble - messagePowerOffsetGroupB; or

4 >

if the Random Access procedure was initiated for the CCCH logical channel and the CCCH SDU size plus MAC subheader is greater than ra-MsgA-SizeGroupA:

5 >

select the Random Access Preambles group B.

4 >

else:

5 >

select the Random Access Preambles group A.

3 >

else:

4 >

select the Random Access Preambles group A.

2 >

else if contention-free Random Access Resources for 2-step RA type have been configured and if Random Access Preambles group has not yet been selected during the current Random Access procedure:

3 >

if Random Access Preambles group B for 2-step RA type is configured; and

3 >

if the transport block size of the MSGA payload configured in the rach-ConfigDedicated corresponds to the transport block size of the MSGA payload associated with Random Access Preambles group B:

4 >

select the Random Access Preambles group B.

3 >

else:

4 >

select the Random Access Preambles group A.

2 >

else (i.e. Random Access preambles group has been selected during the current Random Access procedure):

3 >

select the same group of Random Access Preambles as was used for the Random Access Preamble transmission attempt corresponding to the earlier transmission of MSGA.

2 >

select a Random Access Preamble randomly with equal probability from the 2-step RA type Random Access Preambles associated with the selected SSB and the selected Random Access Preambles group;

2 >

set the PREAMBLE_INDEX to the selected Random Access Preamble.

1 >

determine the next available PRACH occasion from the PRACH occasions corresponding to the selected SSB permitted by the restrictions given by the msgA-SSB-SharedRO-MaskIndex if configured, or ra-ssb-OccasionMaskIndex if configured, or ssb-SharedRO-MaskIndex if configured (the MAC entity shall select a PRACH occasion randomly with equal probability among the consecutive PRACH occasions allocated for 2-step RA type according to clause 8.1 of TS 38.213 regardless the FR2 UL gap, corresponding to the selected SSB; the MAC entity may take into account the possible occurrence of measurement gaps and MUSIM gaps when determining the next available PRACH occasion corresponding to the selected SSB);

1 >

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

2 >

select a PUSCH occasion from the PUSCH occasions configured in msgA-CFRA-PUSCH corresponding to the PRACH slot of the selected PRACH occasion, according to msgA-PUSCH-Resource-Index corresponding to the selected SSB;

2 >

determine the UL grant and the associated HARQ information for the MSGA payload in the selected PUSCH occasion;

2 >

deliver the UL grant and the associated HARQ information to the HARQ entity.

1 >

else:

2 >

select a PUSCH occasion corresponding to the selected preamble and PRACH occasion according to clause 8.1A of TS 38.213;

2 >

determine the UL grant for the MSGA payload according to the PUSCH configuration associated with the selected Random Access Preambles group and determine the associated HARQ information;

2 >

if the selected preamble and PRACH occasion is mapped to a valid PUSCH occasion as specified in clause 8.1A of TS 38.213:

3 >

deliver the UL grant and the associated HARQ information to the HARQ entity.

1 >

perform the MSGA transmission procedure (see clause 5.1.3a).

5.1.3 Random Access Preamble transmission p. 37

The MAC entity shall, for each Random Access Preamble:

1 >

if PREAMBLE_TRANSMISSION_COUNTER is greater than one; and

1 >

if the notification of suspending power ramping counter has not been received from lower layers; and

1 >

if LBT failure indication was not received from lower layers for the last Random Access Preamble transmission; and

1 >

if SSB or CSI-RS selected is not changed from the selection in the last Random Access Preamble transmission; and

1 >

if the Random Access procedure is not initiated by the PDCCH order for an LTM candidate cell:

2 >

increment PREAMBLE_POWER_RAMPING_COUNTER by 1.

1 >

if the Random Access procedure is initiated by the PDCCH order for an LTM candidate cell as preamble re-transmission; and

1 >

if the PDCCH order indicates the same LTM candidate cell and the same SSB as the last Random Access Preamble transmission:

2 >

increment PREAMBLE_POWER_RAMPING_COUNTER by 1.

1 >

select the value of DELTA_PREAMBLE according to clause 7.3;

1 >

set PREAMBLE_RECEIVED_TARGET_POWER to preambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER - 1) × PREAMBLE_POWER_RAMPING_STEP + POWER_OFFSET_2STEP_RA;

1 >

except for contention-free Random Access Preamble for beam failure recovery request and contention-free Random Access Preamble triggered by a PDCCH order for an LTM candidate cell, compute the RA-RNTI associated with the PRACH occasion in which the Random Access Preamble is transmitted;

1 >

instruct the physical layer to transmit the Random Access Preamble using the selected PRACH occasion, corresponding RA-RNTI (if available), PREAMBLE_INDEX, and PREAMBLE_RECEIVED_TARGET_POWER.

1 >

if the Random Access Procedure is triggered by a PDCCH order for an LTM candidate cell:

2 >

consider this Random Access procedure completed.

1 >

if LBT failure indication is received from lower layers for this Random Access Preamble transmission:

2 >

if lbt-FailureRecoveryConfig is configured:

3 >

perform the Random Access Resource selection procedure (see clause 5.1.2).

2 >

else:

3 >

increment PREAMBLE_TRANSMISSION_COUNTER by 1;

3 >

if PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax + 1:

4 >

if the Random Access Preamble is transmitted on the SpCell:

5 >

indicate a Random Access problem to upper layers;

5 >

if this Random Access procedure was triggered for SI request:

6 >

consider the Random Access procedure unsuccessfully completed.

4 >

else if the Random Access Preamble is transmitted on an SCell:

5 >

consider the Random Access procedure unsuccessfully completed.

3 >

if the Random Access procedure is not completed:

4 >

perform the Random Access Resource selection procedure (see clause 5.1.2).

The RA-RNTI associated with the PRACH occasion in which the Random Access Preamble is transmitted or the RA-RNTI associated with the last valid PRACH occasion in the set of PRACH occasions (as specified in TS 38.213) for Msg1 repetition, is computed as:

RA-RNTI = 1 + s_id + 14 × t_id + 14 × 80 × f_id + 14 × 80 × 8 × ul_carrier_id

where s_id is the index of the first OFDM symbol of the PRACH occasion (0 ≤ s_id < 14), t_id is the index of the first slot of the PRACH occasion in a system frame (0 ≤ t_id < 80), where the subcarrier spacing to determine t_id is based on the value of μ specified in clause 5.3.2 of TS 38.211 for μ = {0, 1, 2, 3}, and for μ = {5, 6}, t_id is the index of the 120 kHz slot in a system frame that contains the PRACH occasion (0 ≤ t_id < 80), f_id is the index of the PRACH occasion in the frequency domain (0 ≤ f_id < 8), and ul_carrier_id is the UL carrier used for Random Access Preamble transmission (0 for NUL carrier, and 1 for SUL carrier).

5.1.3a MSGA transmission |R16| p. 38

The MAC entity shall, for each MSGA:

1 >

if PREAMBLE_TRANSMISSION_COUNTER is greater than one; and

1 >

if the notification of suspending power ramping counter has not been received from lower layers; and

1 >

if LBT failure indication was not received from lower layers for the last MSGA Random Access Preamble transmission; and

1 >

if SSB selected is not changed from the selection in the last Random Access Preamble transmission:

2 >

increment PREAMBLE_POWER_RAMPING_COUNTER by 1.

1 >

select the value of DELTA_PREAMBLE according to clause 7.3;

1 >

set PREAMBLE_RECEIVED_TARGET_POWER to msgA-PreambleReceivedTargetPower + DELTA_PREAMBLE + (PREAMBLE_POWER_RAMPING_COUNTER - 1) × PREAMBLE_POWER_RAMPING_STEP;

1 >

if this is the first MSGA transmission within this Random Access procedure:

2 >

if the transmission is not being made for the CCCH logical channel:

3 >

indicate to the Multiplexing and assembly entity to include a C-RNTI MAC CE in the subsequent uplink transmission.

2 >

if the Random Access procedure was initiated for SpCell beam failure recovery and spCell-BFR-CBRA with value true is configured:

3 >

if there is at least one Serving Cell of this MAC entity configured with two BFD-RS sets:

4 >

indicate to the Multiplexing and assembly entity to include an Enhanced BFR MAC CE or a Truncated Enhanced BFR MAC CE in the subsequent uplink transmission.

3 >

else:

4 >

indicate to the Multiplexing and assembly entity to include a BFR MAC CE or a Truncated BFR MAC CE in the subsequent uplink transmission.

2 >

else if the Random Access procedure was initiated for beam failure recovery of both BFD-RS sets of SpCell:

3 >

indicate to the Multiplexing and assembly entity to include an Enhanced BFR MAC CE or a Truncated Enhanced BFR MAC CE in the subsequent uplink transmission.

2 >

obtain the MAC PDU to transmit from the Multiplexing and assembly entity according to the HARQ information determined for the MSGA payload (see clause 5.1.2a) and store it in the MSGA buffer.

1 >

compute the MSGB-RNTI associated with the PRACH occasion in which the Random Access Preamble is transmitted;

1 >

instruct the physical layer to transmit the MSGA using the selected PRACH occasion and the associated PUSCH resource of MSGA (if the selected preamble and PRACH occasion is mapped to a valid PUSCH occasion), using the corresponding RA-RNTI, MSGB-RNTI, PREAMBLE_INDEX, PREAMBLE_RECEIVED_TARGET_POWER, msgA-PreambleReceivedTargetPower, and the amount of power ramping applied to the latest MSGA preamble transmission (i.e. (PREAMBLE_POWER_RAMPING_COUNTER - 1) × PREAMBLE_POWER_RAMPING_STEP);

1 >

if LBT failure indication is received from lower layers for the transmission of this MSGA Random Access Preamble:

2 >

instruct the physical layer to cancel the transmission of the MSGA payload on the associated PUSCH resource;

2 >

if lbt-FailureRecoveryConfig is configured:

3 >

perform the Random Access Resource selection procedure for 2-step RA type (see clause 5.1.2a).

2 >

else:

3 >

increment PREAMBLE_TRANSMISSION_COUNTER by 1;

3 >

if PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax + 1:

4 >

indicate a Random Access problem to upper layers;

4 >

if this Random Access procedure was triggered for SI request:

5 >

consider this Random Access procedure unsuccessfully completed.

3 >

if the Random Access procedure is not completed:

4 >

if msgA-TransMax is applied (see clause 5.1.1a) and PREAMBLE_TRANSMISSION_COUNTER = msgA-TransMax + 1:

5 >

set the RA_TYPE to 4-stepRA;

5 >

perform initialization of variables specific to Random Access type as specified in clause 5.1.1a;

5 >

if the Msg3 buffer is empty:

6 >

obtain the MAC PDU to transmit from the MSGA buffer and store it in the Msg3 buffer;

5 >

flush HARQ buffer used for the transmission of MAC PDU in the MSGA buffer;

5 >

discard explicitly signalled contention-free 2-step RA type Random Access Resources, if any;

5 >

perform the Random Access Resource selection procedure as specified in clause 5.1.2.

4 >

else:

5 >

perform the Random Access Resource selection procedure for 2-step RA type (see clause 5.1.2a).

The MSGB-RNTI associated with the PRACH occasion in which the Random Access Preamble is transmitted, is computed as:

MSGB-RNTI = 1 + s_id + 14 × t_id + 14 × 80 × f_id + 14 × 80 × 8 × ul_carrier_id + 14 × 80 × 8 × 2

5.1.4 Random Access Response reception p. 40

Once the Random Access Preamble is transmitted and regardless of the possible occurrence of a measurement gap, the MAC entity shall:

1 >

if the contention-free Random Access Preamble for beam failure recovery request was transmitted by the MAC entity:

2 >

if the contention-free Random Access Preamble for beam failure recovery request was transmitted on a non-terrestrial network:

3 >

start the ra-ResponseWindow configured in BeamFailureRecoveryConfig at the PDCCH occasion as specified in TS 38.213.

2 >

else:

3 >

start the ra-ResponseWindow configured in BeamFailureRecoveryConfig at the first PDCCH occasion as specified in TS 38.213 from the end of the Random Access Preamble transmission.

2 >

monitor for a PDCCH transmission on the search space indicated by recoverySearchSpaceId of the SpCell identified by the C-RNTI while ra-ResponseWindow is running.

1 >

else:

2 >

if the Random Access Preamble was transmitted on a non-terrestrial network:

3 >

start the ra-ResponseWindow configured in RACH-ConfigCommon at the PDCCH occasion as specified in TS 38.213.

2 >

else if the Random Access Preamble is transmitted with repetitions:

3 >

start the ra-ResponseWindow configured in RACH-ConfigCommon at the first PDCCH occasion from the end of all repetitions of the Random Access Preamble transmission as specified in TS 38.213.

2 >

else:

3 >

start the ra-ResponseWindow configured in RACH-ConfigCommon at the first PDCCH occasion as specified in TS 38.213 from the end of the Random Access Preamble transmission.

2 >

monitor the PDCCH of the SpCell for Random Access Response(s) identified by the RA-RNTI while the ra-ResponseWindow is running.

1 >

if notification of a reception of a PDCCH transmission on the search space indicated by recoverySearchSpaceId is received from lower layers on the Serving Cell where the preamble was transmitted; and

1 >

if PDCCH transmission is addressed to the C-RNTI; and

1 >

if the contention-free Random Access Preamble for beam failure recovery request was transmitted by the MAC entity:

2 >

consider the Random Access procedure successfully completed.

1 >

else if a valid (as specified in TS 38.213) downlink assignment has been received on the PDCCH for the RA-RNTI and the received TB is successfully decoded:

2 >

if the Random Access Response contains a MAC subPDU with Backoff Indicator:

3 >

set the PREAMBLE_BACKOFF to value of the BI field of the MAC subPDU using Table 7.2-1, multiplied with SCALING_FACTOR_BI.

2 >

else:

3 >

set the PREAMBLE_BACKOFF to 0 ms.

2 >

if the Random Access Response contains a MAC subPDU with Random Access Preamble identifier corresponding to the transmitted PREAMBLE_INDEX (see clause 5.1.3):

3 >

consider this Random Access Response reception successful.

2 >

if the Random Access Response reception is considered successful:

3 >

if the Random Access Response includes a MAC subPDU with RAPID only:

4 >

consider this Random Access procedure successfully completed;

4 >

indicate the reception of an acknowledgement for SI request to upper layers.

3 >

else:

4 >

apply the following actions for the Serving Cell where the Random Access Preamble was transmitted:

5 >

process the received Timing Advance Command (see clause 5.2);

5 >

indicate the preambleReceivedTargetPower and the amount of power ramping applied to the latest Random Access Preamble transmission to lower layers (i.e. (PREAMBLE_POWER_RAMPING_COUNTER - 1) × PREAMBLE_POWER_RAMPING_STEP);

5 >

if the Random Access procedure for an SCell is performed on uplink carrier where pusch-Config is not configured:

6 >

ignore the received UL grant.

5 >

else:

6 >

process the received UL grant value and indicate it to the lower layers.

4 >

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

5 >

consider the Random Access procedure successfully completed.

4 >

else:

5 >

set the TEMPORARY_C-RNTI to the value received in the Random Access Response;

5 >

if this is the first successfully received Random Access Response within this Random Access procedure:

6 >

if the transmission is not being made for the CCCH logical channel:

7 >

indicate to the Multiplexing and assembly entity to include a C-RNTI MAC CE in the subsequent uplink transmission.

6 >

if the Random Access procedure was initiated for SpCell beam failure recovery and spCell-BFR-CBRA with value true is configured:

7 >

if there is at least one Serving Cell of this MAC entity configured with two BFD-RS sets:

8 >

indicate to the Multiplexing and assembly entity to include an Enhanced BFR MAC CE or a Truncated Enhanced BFR MAC CE in the subsequent uplink transmission.

7 >

else:

8 >

indicate to the Multiplexing and assembly entity to include a BFR MAC CE or a Truncated BFR MAC CE in the subsequent uplink transmission.

6 >

else if the Random Access procedure was initiated for beam failure recovery of both BFD-RS sets of SpCell:

7 >

indicate to the Multiplexing and assembly entity to include an Enhanced BFR MAC CE or a Truncated Enhanced BFR MAC CE in the subsequent uplink transmission.

6 >

obtain the MAC PDU to transmit from the Multiplexing and assembly entity and store it in the Msg3 buffer.

1 >

if ra-ResponseWindow configured in BeamFailureRecoveryConfig expires and if a PDCCH transmission on the search space indicated by recoverySearchSpaceId addressed to the C-RNTI has not been received on the Serving Cell where the preamble was transmitted; or

1 >

if ra-ResponseWindow configured in RACH-ConfigCommon expires, and if the Random Access Response containing Random Access Preamble identifiers that matches the transmitted PREAMBLE_INDEX has not been received:

2 >

consider the Random Access Response reception not successful;

2 >

increment PREAMBLE_TRANSMISSION_COUNTER by 1;

2 >

if PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax + 1:

3 >

if the Random Access Preamble is transmitted on the SpCell:

4 >

indicate a Random Access problem to upper layers;

4 >

if this Random Access procedure was triggered for SI request:

5 >

consider the Random Access procedure unsuccessfully completed.

3 >

else if the Random Access Preamble is transmitted on an SCell:

4 >

consider the Random Access procedure unsuccessfully completed.

2 >

if the Random Access procedure is not completed:

3 >

if the Random Access Preamble is transmitted with repetitions and neither contention-free Random Access Resources nor Random Access resources for SI request have been provided for this Random Access procedure:

4 >

if PREAMBLE_TRANSMISSION_COUNTER = [preambleTransMax-Msg1-Repetition] + 1; or

4 >

if PREAMBLE_TRANSMISSION_COUNTER = 2 × [preambleTransMax-Msg1-Repetition] + 1:

5 >

if set of Random Access resources configured with the same prach-ConfigurationIndex and associated with a higher Msg1 repetition number with the same feature or feature combination as the current set of Random Access resources is available:

6 >

select the set of Random Access resources associated with the next higher Msg1 repetition number with the same feature or feature combination for this Random Access procedure;

6 >

initialize startPreambleForThisPartition, numberOfPreamblesPerSSB-ForThisPartition, ssb-SharedRO-MaskIndex and numberOfRA-PreamblesGroupA parameters for the Random Access procedure according to the values configured by RRC for the selected set of Random Access resources.

3 >

select a random backoff time according to a uniform distribution between 0 and the PREAMBLE_BACKOFF;

3 >

if the criteria (as defined in clause 5.1.2) to select contention-free Random Access Resources is met during the backoff time:

4 >

perform the Random Access Resource selection procedure (see clause 5.1.2).

3 >

else if the Random Access procedure for an SCell is performed on uplink carrier where pusch-Config is not configured:

4 >

delay the subsequent Random Access transmission until the Random Access Procedure is triggered by a PDCCH order with the same ra-PreambleIndex, ra-ssb-OccasionMaskIndex, and UL/SUL indicator TS 38.212.

3 >

else:

4 >

perform the Random Access Resource selection procedure (see clause 5.1.2) after the backoff time.

The MAC entity may stop ra-ResponseWindow (and hence monitoring for Random Access Response(s)) after successful reception of a Random Access Response containing Random Access Preamble identifiers that matches the transmitted PREAMBLE_INDEX.

HARQ operation is not applicable to the Random Access Response reception.

5.1.4a MSGB reception and contention resolution for 2-step RA type |R16| p. 43

Once the MSGA preamble is transmitted, regardless of the possible occurrence of a measurement gap, the MAC entity shall:

1 >

start the msgB-ResponseWindow at the PDCCH occasion as specified in clause 8.2A of TS 38.213;

1 >

monitor the PDCCH of the SpCell for a Random Access Response identified by MSGB-RNTI while the msgB-ResponseWindow is running;

1 >

if C-RNTI MAC CE was included in the MSGA:

2 >

monitor the PDCCH of the SpCell for Random Access Response identified by the C-RNTI while the msgB-ResponseWindow is running.

1 >

if notification of a reception of a PDCCH transmission of the SpCell is received from lower layers:

2 >

if the C-RNTI MAC CE was included in MSGA:

3 >

if the Random Access procedure was initiated for SpCell beam failure recovery or for beam failure recovery of both BFD-RS sets of SpCell (as specified in clause 5.17) and the PDCCH transmission is addressed to the C-RNTI:

4 >

consider this Random Access Response reception successful;

4 >

stop the msgB-ResponseWindow;

4 >

consider this Random Access procedure successfully completed.

3 >

else if the timeAlignmentTimer associated with at least one PTAG is running; or

3 >

if CG-SDT procedure is ongoing and cg-SDT-TimeAlignmentTimer is running:

4 >

if the PDCCH transmission is addressed to the C-RNTI and contains a UL grant for a new transmission:

5 >

consider this Random Access Response reception successful;

5 >

stop the msgB-ResponseWindow;

5 >

consider this Random Access procedure successfully completed.

3 >

else:

4 >

if a downlink assignment has been received on the PDCCH for the C-RNTI and the received TB is successfully decoded:

5 >

if the MAC PDU contains the Absolute Timing Advance Command MAC CE:

6 >

process the received Timing Advance Command (see clause 5.2);

6 >

consider this Random Access Response reception successful;

6 >

stop the msgB-ResponseWindow;

6 >

consider this Random Access procedure successfully completed and finish the disassembly and demultiplexing of the MAC PDU.

2 >

if a valid (as specified in TS 38.213) downlink assignment has been received on the PDCCH for the MSGB-RNTI and the received TB is successfully decoded:

3 >

if the MSGB contains a MAC subPDU with Backoff Indicator:

4 >

set the PREAMBLE_BACKOFF to value of the BI field of the MAC subPDU using Table 7.2-1, multiplied with SCALING_FACTOR_BI.

3 >

else:

4 >

set the PREAMBLE_BACKOFF to 0 ms.

3 >

if the MSGB contains a fallbackRAR MAC subPDU; and

3 >

if the Random Access Preamble identifier in the MAC subPDU matches the transmitted PREAMBLE_INDEX (see clause 5.1.3a):

4 >

consider this Random Access Response reception successful;

4 >

apply the following actions for the SpCell:

5 >

process the received Timing Advance Command (see clause 5.2);

5 >

indicate the msgA-PreambleReceivedTargetPower and the amount of power ramping applied to the latest Random Access Preamble transmission to lower layers (i.e. (PREAMBLE_POWER_RAMPING_COUNTER - 1) × PREAMBLE_POWER_RAMPING_STEP);

5 >

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

6 >

consider the Random Access procedure successfully completed;

6 >

process the received UL grant value and indicate it to the lower layers.

5 >

else:

6 >

set the TEMPORARY_C-RNTI to the value received in the Random Access Response;

6 >

if the Msg3 buffer is empty:

7 >

obtain the MAC PDU to transmit from the MSGA buffer and store it in the Msg3 buffer;

6 >

process the received UL grant value and indicate it to the lower layers and proceed with Msg3 transmission.

3 >

else if the MSGB contains a successRAR MAC subPDU; and

3 >

if the CCCH SDU was included in the MSGA and the UE Contention Resolution Identity in the MAC subPDU matches the CCCH SDU:

4 >

stop msgB-ResponseWindow;

4 >

if this Random Access procedure was initiated for SI request:

5 >

indicate the reception of an acknowledgement for SI request to upper layers.

4 >

else:

5 >

set the C-RNTI to the value received in the successRAR;

5 >

apply the following actions for the SpCell:

6 >

process the received Timing Advance Command (see clause 5.2);

6 >

4 >

deliver the TPC, PUCCH resource Indicator, ChannelAccess-CPext (if indicated), and HARQ feedback Timing Indicator received in successRAR to lower layers.

4 >

consider this Random Access Response reception successful;

4 >

consider this Random Access procedure successfully completed;

4 >

finish the disassembly and demultiplexing of the MAC PDU.

1 >

if msgB-ResponseWindow expires, and the Random Access Response Reception has not been considered as successful based on descriptions above:

2 >

increment PREAMBLE_TRANSMISSION_COUNTER by 1;

2 >

if PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax + 1:

3 >

indicate a Random Access problem to upper layers;

3 >

if this Random Access procedure was triggered for SI request:

4 >

consider this Random Access procedure unsuccessfully completed.

2 >

if the Random Access procedure is not completed:

3 >

if msgA-TransMax is applied (see clause 5.1.1a) and PREAMBLE_TRANSMISSION_COUNTER = msgA-TransMax + 1:

4 >

set the RA_TYPE to 4-stepRA;

4 >

perform initialization of variables specific to Random Access type as specified in clause 5.1.1a;

4 >

if the Msg3 buffer is empty:

5 >

obtain the MAC PDU to transmit from the MSGA buffer and store it in the Msg3 buffer;

4 >

flush HARQ buffer used for the transmission of MAC PDU in the MSGA buffer;

4 >

discard explicitly signalled contention-free 2-step RA type Random Access Resources, if any;

4 >

perform the Random Access Resource selection procedure as specified in clause 5.1.2.

3 >

else:

4 >

select a random backoff time according to a uniform distribution between 0 and the PREAMBLE_BACKOFF;

4 >

if the criteria (as defined in clause 5.1.2a) to select contention-free Random Access Resources is met during the backoff time:

5 >

perform the Random Access Resource selection procedure for 2-step RA type Random Access (see clause 5.1.2a).

4 >

else:

5 >

perform the Random Access Resource selection procedure for 2-step RA type Random Access (see clause 5.1.2a) after the backoff time.

Upon receiving a fallbackRAR, the MAC entity may stop msgB-ResponseWindow once the Random Access Response reception is considered as successful.

5.1.5 Contention Resolution p. 46

Once Msg3 is transmitted the MAC entity shall:

1 >

if the Msg3 transmission (i.e. initial transmission or HARQ retransmission) is scheduled with PUSCH repetition Type A:

2 >

if Msg3 is transmitted on a non-terrestrial network:

3 >

start or restart the ra-ContentionResolutionTimer in the first symbol after the end of all repetitions of the Msg3 transmission plus the UE-gNB RTT.

2 >

else:

3 >

start or restart the ra-ContentionResolutionTimer in the first symbol after the end of all repetitions of the Msg3 transmission.

1 >

else if Msg3 transmission (i.e. initial transmission or HARQ retransmission) is transmitted on a non-terrestrial network:

2 >

start or restart the ra-ContentionResolutionTimer in the first symbol after the end of the Msg3 transmission plus the UE-gNB RTT.

1 >

else:

2 >

start or restart the ra-ContentionResolutionTimer in the first symbol after the end of the Msg3 transmission.

1 >

monitor the PDCCH while the ra-ContentionResolutionTimer is running regardless of the possible occurrence of a measurement gap;

1 >

if notification of a reception of a PDCCH transmission of the SpCell is received from lower layers:

2 >

if the C-RNTI MAC CE was included in Msg3:

3 >

if the Random Access procedure was initiated by a PDCCH order and the PDCCH transmission is addressed to the C-RNTI; or

3 >

if the Random Access procedure was initiated by the MAC sublayer itself or by the RRC sublayer and the PDCCH transmission is addressed to the C-RNTI and contains a UL grant for a new transmission:

4 >

consider this Contention Resolution successful;

4 >

stop ra-ContentionResolutionTimer;

4 >

discard the TEMPORARY_C-RNTI;

4 >

consider this Random Access procedure successfully completed.

2 >

else if the CCCH SDU was included in Msg3 and the PDCCH transmission is addressed to its TEMPORARY_C-RNTI:

3 >

if the MAC PDU is successfully decoded:

4 >

stop ra-ContentionResolutionTimer;

4 >

if the MAC PDU contains a UE Contention Resolution Identity MAC CE; and

4 >

if the UE Contention Resolution Identity in the MAC CE matches the CCCH SDU transmitted in Msg3:

5 >

consider this Contention Resolution successful and finish the disassembly and demultiplexing of the MAC PDU;

5 >

if this Random Access procedure was initiated for SI request:

6 >

indicate the reception of an acknowledgement for SI request to upper layers.

5 >

else:

6 >

set the C-RNTI to the value of the TEMPORARY_C-RNTI;

5 >

discard the TEMPORARY_C-RNTI;

5 >

consider this Random Access procedure successfully completed.

4 >

else:

5 >

discard the TEMPORARY_C-RNTI;

5 >

consider this Contention Resolution not successful and discard the successfully decoded MAC PDU.

3 >

else, for eRedCap UE, if lower layer detects that PDSCH transmission scheduled by PDCCH has a larger bandwidth than UE can receive or process per slot:

4 >

stop ra-ContentionResolutionTimer;

4 >

discard the TEMPORARY_C-RNTI;

4 >

consider this Contention Resolution not successful.

1 >

if ra-ContentionResolutionTimer expires:

2 >

if Msg3 transmission was transmitted on a non-terrestrial network:

3 >

if no PDCCH addressed to TC-RNTI indicating uplink grant for a Msg3 retransmission is received after the start of the ra-ContentionResolutionTimer:

4 >

discard the TEMPORARY_C-RNTI;

4 >

consider the Contention Resolution not successful.

2 >

else:

3 >

discard the TEMPORARY_C-RNTI;

3 >

consider the Contention Resolution not successful.

1 >

if the Contention Resolution is considered not successful:

2 >

flush the HARQ buffer used for transmission of the MAC PDU in the Msg3 buffer;

2 >

increment PREAMBLE_TRANSMISSION_COUNTER by 1;

2 >

if PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax + 1:

3 >

indicate a Random Access problem to upper layers.

3 >

if this Random Access procedure was triggered for SI request:

4 >

consider the Random Access procedure unsuccessfully completed.

2 >

if the Random Access procedure is not completed:

3 >

if the RA_TYPE is set to 4-stepRA:

4 >

if the Random Access Preamble is transmitted with repetitions and contention-free Random Access Resources have not been provided for this Random Access procedure:

5 >

if PREAMBLE_TRANSMISSION_COUNTER = [preambleTransMax-Msg1-Repetition] + 1; or

5 >

if PREAMBLE_TRANSMISSION_COUNTER = 2 × [preambleTransMax-Msg1-Repetition] + 1:

6 >

7 >

select the set of Random Access resources associated with the next higher Msg1 repetition number with the same feature or feature combination for this Random Access procedure;

7 >

4 >

select a random backoff time according to a uniform distribution between 0 and the PREAMBLE_BACKOFF;

4 >

if the criteria (as defined in clause 5.1.2) to select contention-free Random Access Resources is met during the backoff time:

5 >

perform the Random Access Resource selection procedure (see clause 5.1.2);

4 >

else:

5 >

perform the Random Access Resource selection procedure (see clause 5.1.2) after the backoff time.

3 >

else (i.e. the RA_TYPE is set to 2-stepRA):

4 >

if msgA-TransMax is applied (see clause 5.1.1a) and PREAMBLE_TRANSMISSION_COUNTER = msgA-TransMax + 1:

5 >

set the RA_TYPE to 4-stepRA;

5 >

perform initialization of variables specific to Random Access type as specified in clause 5.1.1a;

5 >

flush HARQ buffer used for the transmission of MAC PDU in the MSGA buffer;

5 >

discard explicitly signalled contention-free 2-step RA type Random Access Resources, if any;

5 >

perform the Random Access Resource selection as specified in clause 5.1.2.

4 >

else:

5 >

select a random backoff time according to a uniform distribution between 0 and the PREAMBLE_BACKOFF;

5 >

if the criteria (as defined in clause 5.1.2a) to select contention-free Random Access Resources is met during the backoff time:

6 >

perform the Random Access Resource selection procedure for 2-step RA type as specified in clause 5.1.2a.

5 >

else:

6 >

perform the Random Access Resource selection for 2-step RA type procedure (see clause 5.1.2a) after the backoff time.

5.1.6 Completion of the Random Access procedure p. 48

Upon completion of the Random Access procedure, the MAC entity shall:

1 >

discard any explicitly signalled contention-free Random Access Resources for 2-step RA type and 4-step RA type except the 4-step RA type contention-free Random Access Resources for beam failure recovery request, if any;

1 >

flush the HARQ buffer used for transmission of the MAC PDU in the Msg3 buffer and the MSGA buffer.

Upon successful completion of the Random Access procedure initiated for DAPS handover, the target MAC entity shall:

1 >

indicate the successful completion of the Random Access procedure to the upper layers.