5.18 Handling of MAC CEs

38.3213GPPMedium Access Control (MAC) protocol specificationNRRelease 17TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

5.18.1 General

This clause specifies the requirements upon reception of the following MAC CEs:

– SP CSI-RS/CSI-IM Resource Set Activation/Deactivation MAC CE;

– Aperiodic CSI Trigger State Subselection MAC CE;

– TCI States Activation/Deactivation for UE-specific PDSCH MAC CE;

– TCI State Indication for UE-specific PDCCH MAC CE;

– SP CSI reporting on PUCCH Activation/Deactivation MAC CE;

– SP SRS Activation/Deactivation MAC CE;

– PUCCH spatial relation Activation/Deactivation MAC CE;

– Enhanced PUCCH spatial relation Activation/Deactivation MAC CE;

– SP ZP CSI-RS Resource Set Activation/Deactivation MAC CE;

– Recommended Bit Rate MAC CE;

– Enhanced SP/AP SRS Spatial Relation Indication MAC CE;

– SRS Pathloss Reference RS Update MAC CE;

– PUSCH Pathloss Reference RS Update MAC CE;

– Serving Cell set based SRS Spatial Relation Indication MAC CE;

– SP Positioning SRS Activation/Deactivation MAC CE;

– Timing Delta MAC CE;

– Guard Symbols MAC CEs;

– Positioning Measurement Gap Activation/Deactivation Command MAC CE;

– PPW Activation/Deactivation Command MAC CE;

– PUCCH spatial relation Activation/Deactivation for multiple TRP PUCCH repetition MAC CE;

– PUCCH Power Control Set Update for multiple TRP PUCCH repetition MAC CE;

– Unified TCI States Activation/Deactivation for UE-specific PDSCH MAC CE;

– Differential Koffset MAC CE.

5.18.2 Activation/Deactivation of Semi-persistent CSI-RS/CSI-IM resource set

The network may activate and deactivate the configured Semi-persistent CSI-RS/CSI-IM resource sets of a Serving Cell by sending the SP CSI-RS/CSI-IM Resource Set Activation/Deactivation MAC CE described in clause 6.1.3.12. The configured Semi-persistent CSI-RS/CSI-IM resource sets are initially deactivated upon (re-)configuration by upper layers and after reconfiguration with sync.

The MAC entity shall:

1> if the MAC entity receives an SP CSI-RS/CSI-IM Resource Set Activation/Deactivation MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the SP CSI-RS/CSI-IM Resource Set Activation/Deactivation MAC CE.

5.18.3 Aperiodic CSI Trigger State Subselection

The network may select among the configured aperiodic CSI trigger states of a Serving Cell by sending the Aperiodic CSI Trigger State Subselection MAC CE described in clause 6.1.3.13.

The MAC entity shall:

1> if the MAC entity receives an Aperiodic CSI trigger State Subselection MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding Aperiodic CSI trigger State Subselection MAC CE.

5.18.4 Activation/Deactivation of UE-specific PDSCH TCI state

The network may activate and deactivate the configured TCI states for PDSCH of a Serving Cell or a set of Serving Cells configured in simultaneousTCI-UpdateList1 or simultaneousTCI-UpdateList2 by sending the TCI States Activation/Deactivation for UE-specific PDSCH MAC CE described in clause 6.1.3.14. The network may activate and deactivate the configured TCI states for a codepoint of the DCI Transmission configuration indication field as specified in TS 38.212 [9] for PDSCH of a Serving Cell by sending the Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE described in clause 6.1.3.24. The configured TCI states for PDSCH are initially deactivated upon (re-)configuration by upper layers and after reconfiguration with sync.

The MAC entity shall:

1> if the MAC entity receives a TCI States Activation/Deactivation for UE-specific PDSCH MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the TCI States Activation/Deactivation for UE-specific PDSCH MAC CE.

1> if the MAC entity receives an Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the Enhanced TCI States Activation/Deactivation for UE-specific PDSCH MAC CE.

5.18.5 Indication of TCI state for UE-specific PDCCH

The network may indicate a TCI state for PDCCH reception for a CORESET of a Serving Cell or a set of Serving Cells configured in simultaneousTCI-UpdateList1 or simultaneousTCI-UpdateList2 by sending the TCI State Indication for UE-specific PDCCH MAC CE described in clause 6.1.3.15. The network may also indicate two TCI states for PDCCH reception for a CORESET of a Serving Cell or a set of Serving Cells configured in simultaneousTCI-UpdateList1 or simultaneousTCI-UpdateList2 by sending the Enhanced TCI States Indication for UE-specific PDCCH MAC CE described in clause 6.1.3.44.

The MAC entity shall:

1> if the MAC entity receives a TCI State Indication for UE-specific PDCCH MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the TCI State Indication for UE-specific PDCCH MAC CE.

1> if the MAC entity receives an Enhanced TCI States Indication for UE-specific PDCCH MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the Enhanced TCI States Indication for UE-specific PDCCH MAC CE.

5.18.6 Activation/Deactivation of Semi-persistent CSI reporting on PUCCH

The network may activate and deactivate the configured Semi-persistent CSI reporting on PUCCH of a Serving Cell by sending the SP CSI reporting on PUCCH Activation/Deactivation MAC CE described in clause 6.1.3.16. The configured Semi-persistent CSI reporting on PUCCH is initially deactivated upon (re-)configuration by upper layers and after reconfiguration with sync.

The MAC entity shall:

1> if the MAC entity receives an SP CSI reporting on PUCCH Activation/Deactivation MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the SP CSI reporting on PUCCH Activation/Deactivation MAC CE.

5.18.7 Activation/Deactivation of Semi-persistent SRS and Indication of spatial relation of SP/AP SRS

The network may activate and deactivate the configured Semi-persistent SRS resource sets of a Serving Cell by sending the SP SRS Activation/Deactivation MAC CE described in clause 6.1.3.17. The network may also activate and deactivate the configured Semi-persistent SRS resource sets of a Serving Cell by sending the Enhanced SP/AP SRS Spatial Relation Indication MAC CE described in clause 6.1.3.26. The network may also activate and deactivate the configured Semi-persistent SRS resource sets of a Serving Cell by sending the SP/AP SRS TCI State Indication MAC CE described in clause 6.1.3.59. The configured Semi-persistent SRS resource sets are initially deactivated upon (re-)configuration by upper layers and after reconfiguration with sync. The network may indicate the spatial relation info of SP/AP SRS resource sets of a Serving Cell by sending the Enhanced SP/AP SRS spatial relation Indication MAC CE described in clause 6.1.3.26.

The MAC entity shall:

1> if the MAC entity receives an SP SRS Activation/Deactivation MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the SP SRS Activation/Deactivation MAC CE.

1> if the MAC entity receives an Enhanced SP/AP SRS Spatial Relation Indication MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the Enhanced SP/AP SRS Spatial Relation Indication MAC CE.

1> if the MAC entity receives an SP/AP SRS TCI State Indication MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the SP/AP SRS TCI State Indication MAC CE.

5.18.8 Activation/Deactivation of spatial relation of PUCCH resource

The network may activate and deactivate a spatial relation for a PUCCH resource of a Serving Cell by sending the PUCCH spatial relation Activation/Deactivation MAC CE described in clause 6.1.3.18. The network may also activate and deactivate a spatial relation for a PUCCH resource or a PUCCH resource group of a Serving Cell by sending the Enhanced PUCCH spatial relation Activation/Deactivation MAC CE described in clause 6.1.3.25. The configured spatial relation for a PUCCH resource is initially deactivated upon (re-)configuration by upper layers and after reconfiguration with sync. The network may also activate and deactivate the two spatial relations for a PUCCH resource or a PUCCH resource group of a Serving Cell by sending the PUCCH spatial relation Activation/Deactivation for multiple TRP PUCCH repetition MAC CE described in clause 6.1.3.45.

The MAC entity shall:

1> if the MAC entity receives a PUCCH spatial relation Activation/Deactivation MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the PUCCH spatial relation Activation/Deactivation MAC CE.

1> if the MAC entity receives an Enhanced PUCCH spatial relation Activation/Deactivation MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the Enhanced PUCCH spatial relation Activation/Deactivation MAC CE.

1> if the MAC entity receives a PUCCH spatial relation Activation/Deactivation for multiple TRP PUCCH repetition MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the PUCCH spatial relation Activation/Deactivation for multiple TRP PUCCH repetition MAC CE.

5.18.9 Activation/Deactivation of semi-persistent ZP CSI-RS resource set

The network may activate and deactivate the configured Semi-persistent ZP CSI-RS resource set of a Serving Cell by sending the SP ZP CSI-RS Resource Set Activation/Deactivation MAC CE described in clause 6.1.3.19. The configured Semi-persistent ZP CSI-RS resource sets are initially deactivated upon (re-)configuration by upper layers and after reconfiguration with sync.

The MAC entity shall:

1> if the MAC entity receives an SP ZP CSI-RS Resource Set Activation/Deactivation MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the SP ZP CSI-RS Resource Set Activation/Deactivation MAC CE.

5.18.10 Recommended Bit Rate

The recommended bit rate procedure is used to provide the MAC entity with information about the bit rate which the gNB recommends. The bit rate is the recommended bit rate of the physical layer. Averaging window of default value 2000 ms will apply as specified in TS 26.114 [13].

The gNB may transmit the Recommended bit rate MAC CE to the MAC entity to indicate the recommended bit rate for the UE for a specific logical channel and a specific direction (either uplink or downlink). Upon reception of a Recommended bit rate MAC CE the MAC entity shall:

– indicate to upper layers the recommended bit rate for the indicated logical channel and direction.

The MAC entity may request the gNB to indicate the recommended bit rate for a specific logical channel and a specific direction. If the MAC entity is requested by upper layers to query the gNB for the recommended bit rate for a logical channel and for a direction (i.e. for uplink or downlink), the MAC entity shall:

1> if a Recommended bit rate query for this logical channel and this direction has not been triggered:

2> trigger a Recommended bit rate query for this logical channel, direction, and desired bit rate.

If the MAC entity has UL resources allocated for new transmission the MAC entity shall:

1> for each Recommended bit rate query that the Recommended Bit Rate procedure determines has been triggered and not cancelled:

2> if bitRateQueryProhibitTimer for the logical channel and the direction of this Recommended bit rate query is configured, and it is not running; and

2> if the MAC entity has UL resources allocated for new transmission and the allocated UL resources can accommodate a Recommended bit rate MAC CE plus its subheader as a result of LCP as defined in clause 5.4.3.1:

3> instruct the Multiplexing and Assembly procedure to generate the Recommended bit rate MAC CE for the logical channel and the direction of this Recommended bit rate query;

3> start the bitRateQueryProhibitTimer for the logical channel and the direction of this Recommended bit rate query;

3> cancel this Recommended bit rate query.

5.18.11 Void

5.18.12 Void

5.18.13 Void

5.18.14 Update of Pathloss Reference RS of SRS

The network may activate and update a pathloss reference RS for an SRS resource of a Serving Cell by sending the SRS Pathloss Reference RS Update MAC CE described in clause 6.1.3.27.

The MAC entity shall:

1> if the MAC entity receives an SRS Pathloss Reference RS Update MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the SRS Pathloss Reference RS Update MAC CE.

5.18.15 Update of Pathloss Reference RS of PUSCH

The network may activate and update a pathloss reference RS for PUSCH of a Serving Cell by sending the PUSCH Pathloss Reference RS Update MAC CE described in clause 6.1.3.28.

The MAC entity shall:

1> if the MAC entity receives a PUSCH Pathloss Reference RS Update MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the PUSCH Pathloss Reference RS Update MAC CE.

5.18.16 Indication of spatial relation of SRS resource for a Serving Cell set

The network may indicate the spatial relation info of SRS resource of a set of Serving Cells configured in simultaneousSpatial-UpdatedList1 or simultaneousSpatial-UpdatedList2 by sending the Serving Cell set based SRS Spatial Relation Indication MAC CE and the Serving Cell Set based SRS TCI State Indication MAC CE described in clause 6.1.3.29 and 6.1.3.60, respectively.

The MAC entity shall:

1> if the MAC entity receives a Serving Cell set based SRS Spatial Relation Indication MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the Serving Cell set based SRS Spatial Relation Indication MAC CE.

1> if the MAC entity receives a Serving Cell Set based SRS TCI State Indication MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the Serving Cell Set based SRS TCI State Indication MAC CE.

5.18.17 Activation/Deactivation of Semi-Persistent Positioning SRS

The network may activate and deactivate the configured resource sets of Semi-Persistent Positioning SRS of a Serving Cell by sending the SP Positioning SRS Activation/Deactivation MAC CE described in clause 6.1.3.36. The configured resource sets Semi-Persistent Positioning SRS are initially deactivated upon (re-)configuration by upper layers and after reconfiguration with sync.

The MAC entity shall:

1> if the MAC entity receives an SP Positioning SRS Activation/Deactivation MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the SP Positioning SRS Activation/Deactivation MAC CE.

5.18.18 Timing offset adjustments for IAB

For IAB operation, in order to achieve time-domain synchronization across multiple backhaul hops, a timing adjustment may be provided to an IAB node by its parent node. Two different values may be provided, related to Case-1/Case-6, and Case-7 timing modes respectively. These parameters are applicable only to IAB nodes. The Timing Delta MAC CE carries T_delta which is used to determine the IAB-DU DL Tx timing adjustment for the Case-1 timing mode, and to determine the IAB-DU DL Tx and IAB-MT UL Tx timing adjustment for the Case-6 timing mode. The Case-7 Timing advance offset MAC CE carries T_offset,2 which is used to determine the IAB-MT UL Tx timing adjustment for the Case-7 timing mode.

Upon reception of a Timing Delta MAC CE the IAB node shall:

– apply the value of T_delta as specified in TS 38.213 [6].

Upon reception of a Case-7 Timing advance offset MAC CE the IAB node shall:

– apply the value of T_offset,2 as specified in TS 38.213 [6].

5.18.19 Guard symbols for IAB

For IAB operation, the MAC entity on the IAB-DU or IAB-donor-DU reserves a sufficient number of symbols at the beginning and/or the end of slots where the child IAB-node switches operation from its IAB-DU to its IAB-MT function and operation from its IAB-MT to its IAB-DU function. The MAC entity on the IAB-DU or IAB-donor-DU informs the child node about the number of guard symbols it provides via the Provided Guard Symbols MAC CE. The IAB-MT on the child node may inform the parent IAB-DU or IAB-donor-DU about the number of guard symbols desired via the Desired Guard Symbols MAC CE. IAB-MT transmission timing modes are specified in clause 14 of TS 38.213 [6].

Upon reception of a Provided Guard Symbols MAC CE the MAC entity shall:

– indicate to lower layers the number of provided guard symbols and the SCS configuration for the indicated Serving Cell.

The MAC entity may:

1> if a Desired Guard Symbol query has not been triggered:

2> trigger a Desired Guard Symbol query for this Serving Cell.

If the MAC entity has UL resources allocated for new transmission the MAC entity shall:

1> for each Desired Guard Symbol query that has been triggered and not cancelled:

2> if the allocated UL resources can accommodate a Desired Guard Symbols MAC CE plus its subheader as a result of LCP as defined in clause 5.4.3.1:

3> instruct the Multiplexing and Assembly procedure to generate the Desired Guard Symbols MAC CE;

3> cancel this Desired Guard Symbol query.

For Case-1 timing mode, a separate value for the number of guard symbols is specified for each of the following eight switching scenarios (see Table 5.18.19-1).

Table 5.18.19-1: Switching scenarios and relevant guard symbols for Case-1 timing mode

Switching scenario		Field for number of guard symbols in MAC CE
IAB-MT operation to IAB-DU operation	MT Rx to DU Tx	NmbGS₁
	MT Rx to DU Rx	NmbGS₂
	MT Tx to DU Tx	NmbGS₃
	MT Tx to DU Rx	NmbGS₄
IAB-DU operation to IAB-MT operation	DU Rx to MT Tx	NmbGS₅
	DU Rx to MT Rx	NmbGS₆
	DU Tx to MT Tx	NmbGS₇
	DU Tx to MT Rx	NmbGS₈

For Case-6 and Case-7 timing modes, a separate value for the number of guard symbols is specified for each of the following eight switching scenarios (see Table 5.18.19-2):

Table 5.18.19-2: Switching scenarios and relevant guard symbols for Case-6 and Case-7 timing modes

Switching scenario		Field for number of guard symbols in MAC CE
IAB-MT operation to IAB-DU operation	MT Tx (Case-6) to DU Tx (Case-1)	NmbGS₉
	MT Tx (Case-6) to DU Rx (Case-1)	NmbGS₁₀
	MT Tx (Case-7) to DU Tx (Case-1)	NmbGS₁₁
	MT Tx (Case-7) to DU Rx (Case-1)	NmbGS₁₂
IAB-DU operation to IAB-MT operation	DU Tx (Case-1) to MT Tx (Case-6)	NmbGS₁₃
	DU Rx (Case-1) to MT Tx (Case-6)	NmbGS₁₄
	DU Tx (Case-1) to MT Tx (Case-7)	NmbGS₁₅
	DU Rx (Case-1) to MT Tx (Case-7)	NmbGS₁₆

5.18.20 Positioning Measurement Gap Activation/Deactivation Command

If the UE is configured with pre-configured measurement gaps, the network may send DL MAC CE for Positioning Measurement Gap Activation/Deactivation Command to the UE as in clause 6.1.3.41. For the activated measurement gap, the UE shall follow the specified UE behaviour in clause 5.14.

Upon the reception of the MAC CE for Positioning Measurement Gap Activation/Deactivation Command, the MAC entity shall:

1> if the Measurement Gap Activation/Deactivation Command MAC CE indicates the deactivation of a pre-configured positioning measurement gap:

2> deactivate the positioning measurement gap.

1> else if the Positioning Measurement Gap Activation/Deactivation Command MAC CE indicates the activation of a pre-configured measurement gap:

2> activate the positioning measurement gap and perform the procedure specified in clause 5.14.

5.18.21 PPW Activation/Deactivation Command

If the UE is configured with pre-configured PPW, the network may send DL MAC CE for PPW Activation/Deactivation Command to the UE as in clause 6.1.3.42. For the activated PPW, the UE shall follow the specified UE behaviour in clause 5.24.

Upon activation of DL BWP, the PPW(s) configured for that BWP are considered deactivated. Upon reconfiguration of PPW(s) of the active DL BWP, all the PPW(s) for that BWP are considered deactivated.

Upon the reception of the MAC CE for PPW Activation/Deactivation Command, the MAC entity shall:

1> if the DL MAC CE for PPW Activation/Deactivation Command indicates the deactivation of a pre-configured PPW:

2> deactivate the PPW.

1> else if the DL MAC CE for PPW Activation/Deactivation Command indicates the activation of a pre-configured PPW:

2> activate the PPW according to the procedure specified in clause 5.24.

5.18.22 Update of PUCCH Power Control Set for multiple TRP PUCCH repetition

The network may activate and deactivate PUCCH power control set(s) for multiple TRP PUCCH repetition for a PUCCH resource or a PUCCH resource group of a Serving Cell by sending the PUCCH Power Control Set Update for multiple TRP PUCCH repetition MAC CE described in clause 6.1.3.46.

The MAC entity shall:

1> if the MAC entity receives a PUCCH Power Control Set Update for multiple TRP PUCCH repetition MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the PUCCH power control set update for multiple TRP PUCCH repetition MAC CE.

5.18.23 Unified TCI States Activation/Deactivation MAC CE

The network may activate and deactivate the configured unified TCI states of a Serving Cell or a set of Serving Cells configured in simultaneousU-TCI-UpdateList1, simultaneousU-TCI-UpdateList2, simultaneousU-TCI-UpdateList3 or simultaneousU-TCI-UpdateList4 by sending the Unified TCI States Activation/Deactivation MAC CE described in clause 6.1.3.47. The configured unified TCI states are initially deactivated upon (re-)configuration by upper layers and after reconfiguration with sync.

The MAC entity shall:

1> if the MAC entity receives a Unified TCI States Activation/Deactivation MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the Unified TCI States Activation/Deactivation MAC CE.

5.18.24 Update of Differential Koffset

The network may provide and update the Differential Koffset of a Serving Cell in a non-terrestrial network by sending the Differential Koffset MAC CE described in clause 6.1.3.57.

The MAC entity shall:

1> if the MAC entity receives a Differential Koffset MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the Differential Koffset MAC CE.

5.18.25 BFD-RS Indication MAC CE

The network may activate and deactivate the configured beam failure detection resources of a Serving Cell by sending the BFD-RS indication MAC CE described in clause 6.1.3.58.

The MAC entity shall:

1> if the MAC entity receives a BFD-RS indication MAC CE on a Serving Cell:

2> indicate to lower layers the information regarding the BFD-RS Indication MAC CE.

5.18.26 Restricted and recommended beam indication for IAB

Child IAB-DU Restricted Beam Indication MAC CE is used by an IAB-node to indicate to its child node spatial and frequency resources where simultaneous transmission/reception from the IAB-MT and transmission from the IAB-DU cells is restricted. IAB-MT Recommended Beam Indication MAC CE is used by an IAB-node to indicate to its parent node recommendations for such a restriction. Time resources where these restrictions/recommendations apply are indicated via RRC.

Upon reception of a Child IAB-DU Restricted Beam Indication MAC CE the IAB-node shall:

– apply the configuration signalled in the MAC CE to the time slots indicated in IAB-ResourceConfig (as specified in TS 38.331) which contains IAB-ResourceConfigID parameter which matches the Resource Configuration ID field of the MAC CE.

The MAC entity may:

1> if an IAB-MT Recommended Beam Indication query has not been triggered:

2> trigger an IAB-MT Recommended Beam Indication query for this Serving Cell.

If the MAC entity has UL resources allocated for new transmission the MAC entity shall:

1> for each IAB-MT Recommended Beam Indication query that has been triggered and not cancelled:

2> if the allocated UL resources can accommodate a IAB-MT Recommended Beam Indication MAC CE plus its subheader as a result of LCP as defined in clause 5.4.3.1:

3> instruct the Multiplexing and Assembly procedure to generate the IAB-MT Recommended Beam Indication MAC CE;

3> cancel this IAB-MT Recommended Beam Indication query.

5.18.27 DL TX power adjustment for IAB

DL TX Power Adjustment MAC CE is used by an IAB-node to indicate to its child node spatial and frequency resources where the DL TX power adjustment contained in the MAC CE applies. Desired DL TX Power Adjustment MAC CE is used by an IAB-node to indicate to its parent node recommendations for such a restriction. Time resources where these restrictions/recommendations apply are indicated via RRC.

Upon reception of a DL TX Power Adjustment MAC CE the IAB-node shall:

The MAC entity may:

1> if a Desired DL TX Power Adjustment query has not been triggered:

2> trigger a Desired DL TX Power Adjustment query for this Serving Cell.

If the MAC entity has UL resources allocated for new transmission the MAC entity shall:

1> for each Desired DL TX Power Adjustment query that has been triggered and not cancelled:

2> if the allocated UL resources can accommodate a Desired DL TX Power Adjustment MAC CE plus its subheader as a result of LCP as defined in clause 5.4.3.1:

3> instruct the Multiplexing and Assembly procedure to generate the Desired DL TX Power Adjustment MAC CE;

3> cancel this Desired DL TX Power Adjustment query.

5.18.28 UL PSD range adjustment for IAB

Desired IAB-MT PSD range MAC CE is used by an IAB-node to indicate to its parent node a recommendation of spatial and frequency resources where the desired PSD range, contained in the MAC CE (and provided to help with the node’s UL TX power control) could apply. Time resources where these recommendations apply are indicated via RRC.

The MAC entity may:

1> if a Desired IAB-MT PSD range query has not been triggered:

2> trigger a Desired IAB-MT PSD range query for this Serving Cell.

If the MAC entity has UL resources allocated for new transmission the MAC entity shall:

1> for each Desired IAB-MT PSD range query that has been triggered and not cancelled:

2> if the allocated UL resources can accommodate a Desired IAB-MT PSD range MAC CE plus its subheader as a result of LCP as defined in clause 5.4.3.1:

3> instruct the Multiplexing and Assembly procedure to generate the Desired IAB-MT PSD range MAC CE;

3> cancel this Desired IAB-MT PSD range query.

5.18.29 Timing case indication for IAB

Timing Case Indication MAC CE is used by an IAB-node to indicate to its child node timing modes which should apply to time resources indicated via RRC.

Upon reception of a Timing Case Indication MAC CE the IAB-node shall:

– apply the configuration signalled in the MAC CE to the time slots indicated in IAB-ResourceConfig which contains IAB-ResourceConfigID parameter (as specified in TS 38.331) which matches the Resource Configuration ID field of the MAC CE.