3GPP TSG RAN WG1 #121	R1-2503235
St Julian’s, Malta, May 19th – 23rd, 2025
Agenda Item:	9.5.3
Source:	Futurewei
Title:	Discussion of the adaptation of common signal/channel transmissions
Document for:	Discussion and decision 

Conclusions
In this contribution we analyze and provide possible solutions for the adaptation of common signal/channel transmissions.

Proposal 1: The first slot of the first possible SSB burst (5ms SSB transmission window) is the first slot after the least multiple of the new periodicity after the last SSB transmission burst and later than m+d.

Proposal 2: Support separate configuration of totalNumberOfRA-Preambles and numberOfRA-PreamblesGroupA for additional PRACH resources, at least for 4-step RACH.

Proposal 3: When Msg1-FDM is not configured, reuse the corresponding value from the legacy RO configuration.

Proposal 4: When the 1-bit field in DCI 1_0 with C-RNTI is set to zero, NES capable UEs must not use additional PRACH resources.

Proposal 5: Do not support DCI to explicitly deactivate additional PRACH resources. Instead, rely on the existing 1-bit indication and higher-layer validity duration.

Proposal 6: Leave RA-RNTI ambiguity resolution (when legacy and additional ROs overlap) to RAN2. This aligns with past practice where implementation-specific resolutions were deemed sufficient.

Proposal 7: Leave the configuration of additional PRACH resources for 2-step RACH to RAN2. Given the short Rel-19 timeline, discussion should focus on finalizing support for 4-step RACH.

Proposal 8: R19 NES UEs must prioritize additional PRACH resources when available, falling back to legacy resources only upon failure. This reduces contention and protects legacy UE access latency.

Proposal 9: Time domain adaptation of paging should be left to RAN2 for further specification and implementation alignment, consistent with RAN2#129 agreements.

3GPP TSG-RAN WG1 Meeting #121	R1-2503269
St Julian’s, Malta, May 19th – 23rd, 2025
 
Agenda item:	9.5.3
Source:	Huawei, HiSilicon
Title:	On common channel/signal adaptation for eNES
Document for:	Discussion and Decision

Conclusions
The following observations and proposals are provided.
In TDD system, a valid PRACH Occasion for Type-1 RA needs to start at least a given number of symbols after a last SSB symbol on the PRACH slot, where the SSB position in time is given by SIB1 or RRCReconfiguration.
There are legacy valid ROs that are not mapped to SSB based on current spec. The legacy UE can not use these valid ROs.
In legacy PRACH configuration, totalNumberOfRA-Preambles should be a multiple of the number of SSBs per RACH occasion. And numberOfRA-PreamblesGroupA should be consistent with ssb-perRACH-OccasionAndCB-PreamblesPerSSB.

For DCI 2_9-based SSB burst periodicity adaptation, the reference time for applying the new periodicity is the beginning of the half frame, that appears after slot m+d , with transmission of SS/PBCH blocks assuming the old periodicity.
To address the inter-cell interference issue, the rate-matching pattern on a Rel-19 NES cell is based on all the candidate SSBs indicated by ssb-PositionsInBurst, of which periodicity is the minimum one among the configured values.
The PRACH occasion validation rules should be re-evaluated if SSB adaptation took place.
RAN1 to introduce indication on whether (periodic) CSI-RS resource is valid or not when it is overlapped with the adapted SSB in time domain. 
For PRACH adaptation indication, for idle/inactive UEs, additionally support the use of DCI 2_7  to indicate, using 1-bit, the availability of the additional PRACH resources. 
Adopt TP#1 to clarify the relationship between legacy PRACH resources and additional PRACH resources.
---------------------------------------------------------------------Start of TP#1------------------------------------------------------------
8.1	 Random access preamble

For Type-1 random access procedure, a UE can be provided, by addl-RACH-Config-Adaptation [in RACH-ConfigCommon], parameters for determining time resources and frequency resources for PRACH transmission [4, TS 38.211]. When a PRACH occasion associated with addl-RACH-Config-Adaptation has same frequency resource and same time resource as a valid PRACH occasion [in the RACH-ConfigCommon] that is associated with SS/PBCH block index(es) and not associated with addl-RACH-Config-Adaptation, the former PRACH occasion is not valid and is not considered in the procedures in this clause. 
---------------------------------------------------------------------End of TP#1--------------------------------------------------------------

totalNumberOfRA-Preambles and numberOfRA-PreamblesGroupA can be configured separately for the additional PRACH resources to guarantee consistent setting as in legacy.
Validity time duration can be one SI modification period.
K=1 is supported.
If addl-RACH-Config-Adaptation is configured, additional PRACH availability indication can be carried by a DCI format 1_0 with CRC scrambled by P-RNTI with Short Messages Indicator set to 01.

3GPP TSG RAN WG1 meeting #121		                                   R1-2503317
St Julian's, Malta, May. 19th – May 23rd, 2025
Title: 	Discussion on common signal/channel for NES 
Source: 	ZTE Corporation, Sanechips
Agenda item:	9.5.3
Document for:	Discussion and decision

Conclusion
In this contribution, we have the following observations/proposals:
Proposal 1:	Support to introduce a fallback state (e.g., using original periodicity configured in ssb-PeriodicityServingCell) in the bit field for SSB adaptation in DCI format 2_9.
Proposal 2:	Support that the first SSB burst is based on the SSB configuration with same parameters as those before SSB adaptation with indicated additional SSB burst periodicity in DCI signaling.
Proposal 3:	Support the legacy Rel-15 ROs are used for ‘additional RO validation before the SSB-RO mapping’.
Proposal 4:	Do not support explicit deactivation for additional PRACH resources.
Proposal 5:	Support UEs would regard the additional PRACH resources are deactivated by default before receiving an activation command in the DCI signaling.
Proposal 6:	Discuss the two aspects for C-RNTI DCI based additional PRACH resources adaptation:
•	Which types of additional PRACH resources the C-RNTI DCI can adapt (e.g., CBRA-based PRACH resources or CFRA-based PRACH resources)
•	Which semi-static signaling for configured additional PRACH resources the C-RNTI DCI can adapt. (e.g., additional PRACH resources in SIB1 or additional PRACH resources in RRC signaling).
Proposal 7:	Support reusing the existing bit fields for adaptation of PRACH in time domain in C-RNTI DCI.
Proposal 8:	Consider the legacy application delay of C-RNTI DCI as a starting point for the application delay of C-RNTI DCI.
Proposal 9:	The first applicable PRACH resources should be the first additional PRACH resources satisfying the application delay of C-RNTI.
Proposal 10:	The validity time duration for C-RNTI DCI-based PRACH adaptation can be considered.
Proposal 11:	Support Option 3: PEI bits for legacy POs and additional Rel-19 POs are always or not multiplexed in the same DCI 2_7 are supported via gNB configuration.

3GPP TSG RAN WG1 #121                     		                                                     R1-2503367
St Julian’s, Malta, May 19th – 23rd, 2025
Source: 	vivo
Title:	Remaining issues on adaptation of common signal/channel transmissions
Agenda Item:	9.5.3
Document for:	Discussion and Decision

Conclusion
In this contribution, the following proposals are summarized as follows: 
Proposal 1: For adaptation of SSB in time-domain, SSB burst periodicity adaptation on an SCell is applicable to Scenario 2, Scenario 2A, Scenario 3A, Scenario 3B defined in AI 9.5.1.
Proposal 2: The first possible SSB burst is determined by the indicated SSB burst periodicity and corresponding SMTC.
Proposal 3: The additional RO is invalid by a legacy RO in which the additional RO is within the same configuration of RACH-ConfigCommon in SIB1 of the legacy RO.
Proposal 4: For additional RO configured in RACH-ConfigCommon, the total number for CBRA and CFRA is 64.
Proposal 5: Do not support additional RO configured in RACH-ConfiguredDedicated.
Proposal 6: Whether the additional RO is activated by DCI format 1_0 with P-RNTI or not, the availability of additional RO is according to the indication in DCI format 1_0 with C-RNTI.
Proposal 7: Adopt TP1 of TS 38212.
----------------------------------------------------Start of TP1 of TS 38212-------------------------------------------------
7.3.1.2.1	Format 1_0
< Unchanged parts are omitted >
-	PRACH resource indicator - 0 or 1 bit 
-	1 bit if the UE is configured with higher layer parameter addl-RACH-Config-Adaptation XYZ. This field indicates the availability of the PRACH resource configured by addl-RACH-Config-Adaptation XYZ according to Table 7.3.1.2.1-5. If higher layer parameter occassions is configured in RACH-ConfiguredDedicated and the value of the "Random Access Preamble index" is not all zeros, this field is reserved.

-	0 bit otherwise.
< Unchanged parts are omitted >
----------------------------------------------------End of TP1 of TS 38212-----------------------------------------------------

3GPP TSG RAN WG1 Meeting #121	R1-2503414  St Julian’s, Malta, May 19th – 23th, 2025

Agenda item:		9.5.3
Source:	Nokia, Nokia Shanghai Bell
Title:	Adaptation of Common Signal Channel Transmissions
Document for:		Discussion and Decision

Conclusions
In this contribution, we have the following observations and proposals:
Proposal-1: RAN1 considers the scenarios for SSB burst periodicity adaptation at least with Scenario #3B in AI 9.5.1. 
Observation-1: Further clarifications to DCI format 2_9 would be required if the same DCI could indicate both SSB adaptation and cell DTX/DRX. 
Observation-2: When the DCI 2_9 formats with different RNTI are received in the same slot, R19 UEs will decode both indications and will be able to process them within the same time delay.
Proposal-2: Configurability of the sfn-SSB-offset for the SSBs with adapted burst periodicity can be revisited.
Proposal-3: RAN1 to discuss and decide how adaptation of SSB periodicity affects rate matching operation and CSI measurements and reporting. 
Proposal-4: RAN1 to clarify whether Rel-19 additional ROs could be used for 2-step PRACH procedure and, if yes, how. 
Proposal-5: PRACH adaptation applied to CFRA should also be investigated, if time allows, however no CFRA-specific PRACH adaptation solutions should be considered.
Proposal-6: RAN1 to support the inclusion of 16 in the list of 4 candidate values for K. 
Proposal-7: RAN1 to support default value of K, when this parameter is not configured, and PRACH mask is configured, as K=1. 
Proposal-8: The configuration of the additional PRACH resources shall be provided in the same RACH-ConfigCommon irrespective of the Parent IE in SIB1, used to configure the legacy PRACH resources. Signaling structural details, e.g., which IE would go in RACH-ConfigGeneric, are left to RAN2. 
Proposal-9: RAN1 to also consider the addition of one 1 bit in SIB1 to indicate whether additional ROs can be assumed by the UE as available for PRACH at the time of SIB1 acquisition.
Proposal-10: RAN1 to confirm that no further discussion is needed for the 1-bit field indication in DCI format 1_0 with P-RNTI used for PRACH adaptation indication.
Proposal-11: For PRACH adaptation, when availability of additional ROs is indicated via DCI 1_0 with C-RNTI, PRACH mask applies to either additional ROs or legacy ROs, depending on which one satisfies the conditions for the mask to be applicable, e.g., number of SSB per RO smaller than 1.
Proposal-12: Support the following TP for Clause 8.1 of TS 38.213, as per Editor CR available in R1-2503167.

 

3GPP TSG RAN WG1 #121 Meeting		             		R1-2503418
St Julian’s, Malta, May 19th – 23rd, 2025	
Agenda item:	9.5.3
Source:	NEC
Title:	Discussion on adaptation of common signal/channel transmissions 
Document for:	Discussion 

Conclusion
From the discussion, we have the following proposals:
Proposal 1: For determining PRACH occasion validity, valid PDCCH monitoring occasions, and PDSCH rate matching around SSBs, the UE shall use the lowest  SSB burst periodicity value among all configured SSB burst periodicities for the SCell, irrespective of the dynamically indicated SSB burst periodicity via DCI.
Proposal 2: It is recommended that the SSB burst periodicity configured via legacy signalling (e.g., in ServingCellConfigCommon) corresponds to the lowest SSB burst periodicity intended for the SCell operation.
Proposal 3: Support RRC configuration of a time offset parameter associated with each configured SSB burst periodicity for an SCell. The UE uses the configured offset corresponding to the DCI-indicated periodicity to determine the exact timing occasions for SSB burst transmission starting from the first valid occasion no earlier than slot m+d.
Proposal 4: Support CSI report configuration associated with both of CD-SSB and NCD-SSB (with SSB adaptation) or one of CD-SSB and NCD-SSB based on configuration.
Proposal 5: Support separate configuration of featureCombinationPreamblesList for the additional PRACH resources configured within RACH-ConfigCommon.
Proposal 6: Support gNB to configure one or more values of PRACH validity duration for additional PRACH resources. One of the PRACH validity duration is indicated by the DCI indication for PRACH adaptation which should be used by UE to determine the available PRACH resources.
Proposal 7: If UE receives a PDCCH order and the PDCCH order can indicate availability of additional PRACH resources, the UE selects the PRACH resources for PRACH transmission according to
If additional PRACH resources are not indicated as available, then UE selects the legacy PRACH resources for PRACH transmission
If additional PRACH resources are indicated as available, then UE selects the additional PRACH resources for PRACH transmission
Proposal 8: UE applies the values of Random Access Preamble index and PRACH Mask index to the PRACH resource type (additional vs legacy) selected by UE for PRACH transmission.

3GPP TSG RAN WG1 #121                                                       R1-2503521
St Julian’s, Malta, May 19th – 23th, 2025

Agenda Item:	9.5.3
Source:	Spreadtrum, UNISOC
Title: 	Discussion on adaptation of common signal/channel transmission
Document for:	Discussion and decision

Conclusion
We have the following proposals.
Proposal 1: New RRC signaling is not needed for indication of offset of SSB within the periodicity for the additional SSB periodicity and the same configuration parameters can configured for SSB before adaptation and after adaptation.
Proposal 2: The following working assumption can be confirmed.
Proposal 3: For the cell with RedCap specific initial UL BWP, which initial UL BWP is applicable for the one bit indicating additional PRACH resources need to be clarified.
Proposal 4: For PRACH adaptation indication, support the use of DCI 2_7 for idle/inactive UEs. 
Proposal 5: DCI cannot be used to explicitly deactivate the additional PRACH resources.

3GPP TSG RAN WG1 #121		R1-2503572
St Julian's, Malta, 19th – 23rd May, 2025
Agenda item:	9.5.3
Source:	Samsung
Title:	Adaptation of common signal/channel transmissions
Document for:	Discussion and decision

Conclusion
There is no RAN1 consensus to support time domain adaptation for CD-SSB in Rel-19 for SCell

Agreement
For adaptation of SSB in time-domain, support the following to adapt SSB burst periodicity for an SCell
UE is configured with SSB burst periodicity using legacy signalling for the SCell 
UE is configured with X additional SSB burst periodicity for the SCell
FFS: Value of X
SSB occasions with larger periodicity are subset of the SSB occasions with shorter periodicity
FFS: Whether there is specification impact
Note: This does not impact the discussion on OD-SSB
For switching the periodicity, down-select between 
(MAC-CE) 
MAC-CE details for SSB burst periodicity adaptation is up to RAN2.
(DCI)
Alt 1-3: DCI based signalling is used

Agreement
For adaption of PRACH in time-domain, for a connected mode UE, support a 1-bit field in DCI 1_0 with C-RNTI used to trigger PRACH (i.e. PDCCH order) to indicate whether the additional PRACH resource(s) is available for the triggered PRACH. 
FFS: UE behaviour (e.g. applicable resources for PRACH mask index) when it is indicated of additional PRACH resource(s)
FFS: Details on how to reuse existing bit for the 1-bit indication

Agreement
For DCI-based adaptation for additional PRACH resources, DCI 1_0 with P-RNTI indicates the availability information for additional PRACH resource from a reference point and for a validity time duration
FFS: Validity time duration for availability is configured by higher layer signaling or predefined
FFS: Location of the reference point defined in the specification
FFS: Value/granularity of the validity time duration.
FFS: Whether DCI can be used to explicitly deactivate the additional PRACH resources

Agreement
For DCI-based adaptation for additional PRACH resources, support optional semi-static signalling of a single PRACH mask to identify the subset of the additional PRACH resources 
The mask is applicable at unit of 
Alt 1: PRACH association period 
Alt 2: PRACH association pattern period
Alt 3: SFN level
The PRACH association period is determined based on valid additional ROs only.
The mask is applied after valid RO determination and SSB-RO mapping.
Note: The existing behaviour in TS 38.213 "An association pattern period includes one or more association periods and is determined so that a pattern between PRACH occasions and SS/PBCH block indexes repeats at most every 160 msec." is not impacted due to application of the mask.
This is applicable at least for adaptation for DCI 1_0 with P-RNTI 
The DCI does not indicate PRACH mask selection
FFS: how the mask is identified 
Option 1: The PRACH mask is from a PRACH mask table
Pre-defined table with N=[4 or 8 or 16] rows
The semi-static signalling indicates a PRACH mask index 
Option 2: The PRACH mask is based on configuration parameters e.g. bitmap at SFN-level, periodic time domain window, …

Agreement
Separate configuration of Msg1-FDM for the additional PRACH resources at least for 4-step RACH is supported
UE is not expected to be configured such that there are more than 8 FDM-ed valid ROs (legacy + additional ROs)
FFS: When there is no configuration of Msg1-FDM
Separate configuration of number of SSB per RO is supported

Agreement
Study the following options for the reference point (for the availability information of additional PRACH resources indicated by DCI 1_0 with P-RNTI in a PF) for RRC idle/inactive mode UE and RRC connected mode UE, 
Option 1: SFN of the first PF from the next I-DRX cycle 
Option 2: SFN of the first PF from the current I-DRX cycle 
Option 3: From the first frame of the first PRACH association period after UE receives the DCI
Option 4: From the first frame of the current SI modification period 
Option 5: From the first frame of the next SI modification period

Agreement
For adaptation of SSB in time-domain, for adapting SSB burst periodicity for an SCell
Support group common DCI signalling for switching the SSB burst periodicity using DCI format 2_9 with [cellDTRX-RNTI]
FFS: which scenario(s) is this applicable for (e.g. as defined in 9.5.1)
Note: Above does not prevent RAN2 from designing a MAC CE based on OD-SSB feature and also used for SSB burst adaptation

RAN1#120bis agreements
Agreement
For adaptation of PRACH in time-domain, at least for 4-step RACH, at least for DCI 1_0 with P-RNTI, 
Support configuration of the additional PRACH resources within [the same] RACH-ConfigCommon in SIB1 used to configure the legacy PRACH resources 
the legacy PRACH resources used for ‘additional RO validation before the SSB-RO mapping’ are configured in the RACH-ConfigCommon

Agreement
For DCI-based adaptation for additional PRACH resources, the following 1-bit field is used for adaptation indication in DCI format 1_0 with P-RNTI 
Use one bit from the Bits 5-8 within the Short Message field (from upper layers)
Send LS to RAN2 to confirm the use of this bit.
Above applies for cell that transmits the DCI for connected UEs and IDLE/INACTIVE mode UEs

Agreement
For DCI-based adaptation for additional PRACH resources, for the availability information of additional PRACH resources indicated by DCI 1_0 with P-RNTI 
the validity duration is configured via higher layer signalling.

Agreement
For DCI-based adaptation for additional PRACH resources, PRACH mask that identifies the subset of the additional PRACH resources is applicable at unit of
PRACH association period 
This PRACH mask applies to every [configured] K SSB RO association pattern period(s)

Agreement
For adaptation of SSB in time-domain, for DCI 2_9-based SSB burst periodicity adaptation for an SCell, 
The DCI is scrambled a new RNTI, 
Same search space and DCI size as that of cell DTX/DRX DCI if gNB configures both

Agreement
For DCI 2_9-based SSB burst periodicity adaptation for an SCell
the starting location of the information block for SSB burst periodicity indication for a SCell within the DCI format 2_9 is configured using a new RRC parameter 
the length of the information block is given by ceil(log2(1+X)), where UE is configured with X additional SSB burst periodicities for the SCell

Agreement
For adaptation of SSB in time-domain, UE can be configured with X (<=Xmax) additional SSB burst periodicities for an SCell.
Xmax=2

Agreement
Separate configuration of the following parameters for the additional PRACH resources at least for 4-step RACH is supported
CB-PreamblesPerSSB

Agreement
LS on DCI-based PRACH adaptation endorsed with the ACTION part modified compared to draft LS in R1-2503085 as follows:
ACTION: RAN1 respectfully asks RAN2 to confirm whether the use of above bit is feasible.
Final LS in R1-2503086.

Agreement
For adaptation of PRACH in time-domain, for a connected mode UE, 
One of the reserved bits of PDCCH order (DCI 1_0 with C-RNTI) is used for the new DCI field that indicates the availability of additional PRACH resources.

Working Assumption
When a UE receives in slot  on the active DL BWP of a first serving cell a PDCCH providing DCI format 2_9 that indicates a change in SSB burst periodicity of the SSB transmission on a second serving cell, the UE assumes SSB is transmitted on the second serving cell according to the indicated SSB burst periodicity from the beginning of the first slot containing the first [actually] transmitted SSB within the first [possible] SSB burst according to the indicated SSB burst periodicity that is no earlier than the slot  of the first serving cell where  is a number of slots for the SCS of the active DL BWP of the first serving cell [in Table 11.5-1 of TS 38.213].
FFS: how to determine the first [possible] SSB burst

Agreement
For DCI-based adaptation for additional PRACH resources, the PRACH mask to identify the subset of the additional PRACH resources is given by:
Option 1-2:  Semi-static signalling of a PRACH mask index and a value of K (number of association pattern periods)
For K: one from up to four candidate values {2,4,8, [1 or 16]}

Agreement
For DCI-based adaptation for additional PRACH resources, the reference point for the availability of additional PRACH resources indicated by DCI 1_0 with P-RNTI is the start of first frame of the current SI modification period where UE receives the DCI
The validity duration configured by higher layer signalling for the availability information of additional PRACH resources indicated by DCI 1_0 with P-RNTI is 
(Option 4) Multiple of SI modification period ({[1],2,[3],4,8,[],[],..})

3GPP TSG RAN WG1 #121			R1-2503716
St Julian's, Malta, May 19th – 23, 2025
Source:           Tejas Networks Ltd
Title:                    Adaptation of common signal/channel transmissions for network energy
                         saving
Agenda item:	 9.5.3	
Document for: Discussion and Decision

Conclusions


Define the reference point and time gap between the reference point and first possible SSB burst location to determine the start of the first possible SSB burst, after the DCI indicating new SSB burst periodicity value. 

Confirm the following working assumption made in RAN1#120-bis meeting

When a UE receives in slot m on the active DL BWP of a first serving cell a PDCCH providing DCI format 2_9 that indicates a change in SSB burst periodicity of the SSB transmission on a second serving cell, the UE assumes SSB is transmitted on the second serving cell according to the indicated SSB burst periodicity from the beginning of the first slot containing the first [actually] transmitted SSB within the first [possible] SSB burst according to the indicated SSB burst periodicity that is no earlier than the slot m+d of the first serving cell where d is a number of slots for the SCS of the active DL BWP of the first serving cell [in Table 11.5-1 of TS 38.213].

Support DCI based adaptation of SSB burst periodicity for scenario #3A and scenario #3B defined in agenda item 9.5.1.

The location of the K-APPs in the additional PRACH resource validity duration should be clarified.

For UE to identify the APPs that are masked by the base station within the additional PRACH resource validity duration can be indicated to the UE using two options
Using a bit map to identify the K-APPs within the additional PRACH resource validity duration.
Using start and end indication for the K-APPs assuming that K-APPs are continues in time within the additional PRACH resource validity duration.

About the validity of the additional PRACH resources indicated by the DCI format 1_0 scrambled with C-RNTI following options can be considered
For CBRA, UE assume that additional PRACH resources available till the UE successfully receive the contention resolution message. For CFRA, UE assume that additional PRACH resources are available till the UE successfully receive the RAR.
Additional PRACH resources are available for some validity duration indicated by higher layer parameters.
Combination of above two options can also be considered. 

On the time instance where a UE can start using the additional PRACH resources after the UE receive the availability indication of the additional PRACH resources using DCI format 1_0 scrambled with C-RNTI needs to be defined.

Whether to apply the PRACH mask indicated in the PDCCH order in addition to the PRACH mask defined in the RAN1#120-bis meeting, on the additional PRACH resources, need to be discussed.

A default value (considering that maximum number of FDM RACH resources not exceeding 8) can be considered when Msg1-FDM is not configured. The default value can be 1.

If additional PRACH configuration index is not configured then it will be assumed same as legacy PRACH configuration index.

3GPP TSG RAN WG1 #121	                           R1-2503799
St Julian’s, Malta, May 19th – 23rd, 2025

Source: 	CATT
Title:	Discussion on adaptation of common signal/channel transmissions
Agenda Item:	9.5.3
Document for:	Discussion and Decision

Conclusion
In this contribution, the potential spec impacts for adaptation of common signal/channel transmission are discussed. The observations and proposals are summarized as follows:
Proposal 1: Confirm the following working assumption: 
When a UE receives in slot  on the active DL BWP of a first serving cell a PDCCH providing DCI format 2_9 that indicates a change in SSB burst periodicity of the SSB transmission on a second serving cell, the UE assumes SSB is transmitted on the second serving cell according to the indicated SSB burst periodicity from the beginning of the first slot containing the first [actually] transmitted SSB within the first [possible] SSB burst according to the indicated SSB burst periodicity that is no earlier than the slot  of the first serving cell where  is a number of slots for the SCS of the active DL BWP of the first serving cell [in Table 11.5-1 of TS 38.213].
FFS: how to determine the first [possible] SSB burst
Proposal 2: The first SSB burst can be determined based on the offset between the first SSB in the last SSB burst before the application of the indicated SSB burst periodicity is applied, and the first SSB in the first SSB burst after the application of the indicated SSB burst periodicity is applied. 
The offset can be the shorter SSB burst periodicity between before and after SSB burst periodicity adaptation.
No additional RRC parameter is needed.
Proposal 3: The applied SSB burst periodicity can be configured to the UE by RRC signaling.
Proposal 4: The parameter Msg1-FDM for the additional PRACH resources should be always configured. 
Proposal 5: When the UE receives a PDCCH order indicating the additional RO resource(s) available, the UE can only use additional PRACH resource to initiate RACH.
Proposal 6: PEI bits for legacy POs and additional Rel-19 POs are not multiplexed in DCI 2_7.

3GPP TSG RAN WG1 #121	R1-2503837
Malta, MT, May 19th–May 23th, 2025

Source: 	CMCC
Title:	Discussion on adaptation of common signal/channel transmissions
Agenda item:	9.5.3
Document for:	Discussion/Decision

Conclusion 
In this contribution, we discussed the adaption of common signal/channels, include SSB adaptation in time domain, PRACH adaptation in time domain and Paging adaptation, and the following proposals are made:
Proposal 1: Confirm the following working assumption with further revision:
Working Assumption
When a UE receives in slot  on the active DL BWP of a first serving cell a PDCCH providing DCI format 2_9 that indicates a change in SSB burst periodicity of the SSB transmission on a second serving cell, the UE assumes SSB is transmitted on the second serving cell according to the indicated SSB burst periodicity from the beginning of the first slot containing the first [actually] transmitted SSB within the first [possible] SSB burst according to the indicated SSB burst periodicity that is no earlier than the slot  of the first serving cell where  is a number of slots for the SCS of the active DL BWP of the first serving cell [in Table 10.3-111.5-1 of TS 38.213].
FFS: how to determine the first [possible] SSB burst
The first possible SSB burst is determined based on two parameters, where one is to indicate SFN offset from a reference point and the other is to indicate half frame index.

Proposal 2: RAN1 to further discuss the UE behavior with SSB adaptation under the following procedures:
UE behavior on rate matching of PDSCH
UE behavior on PDCCH monitoring
UE behavior on UL transmission

Proposal 3: Adopt the Text Proposals on SSB adaptation in Annex A.

Proposal 4: For validity duration of PRACH adaptation indicated by Paging DCI, support:
Option 1: 2 SI modification period (starting from the first frame of the current SI modification period), if the starting time for the availability of additional PRACH resources is when UE receives the DCI.
Option 2: 1 SI modification period, if the starting time for the availability of additional PRACH resources is the start of first frame of the next SI modification period where UE receives the DCI.

Proposal 5: RAN1 to further discuss the UE behavior on initial RACH procedure.

Proposal 6: For Paging adaptation, support RAN1 to further discuss:
Whether the existing procedure (e.g., SI update and RRC re-configuration) on indication method is enough or enhancement is needed.
Whether a unified design is needed for indication on common signal adaptation.

3GPP TSG RAN WG1 #120-bis		  R1-2503867
Malta, May 19th – 23rd, 2025

Agenda Item:	9.5.3
Source:	Panasonic
Title:	Discussion on adaptation of common signal/channel transmission
Document for:	Discussion/Decision

Conclusion
Based on the discussion, the following proposals are highlighted:
Proposal 1: Skipping/transmitting some SSB bursts non-uniformly with single SSB configuration can be realized by the functionality defined in on-demand SSB in 9.5.1.
Observation 1: The length of the information block is 2 bits. To indicate a total of three SSB burst periodicities which are allowed, 3 states are sufficient. Hence, 1 state will be reserved.
Proposal 2: The free state can possibly be used to indicate SSB OFF (in agenda 9.5.1).
Observation 2: When adaptation of SSB and Cell DTX/DRX are to be indicated at the same time, it is optimal to use the same DCI 2_9 to indicate both. The value of new RNTI can then be the same as existing cellDTRX-RNTI. When adaptation of SSB and Cell DTX/DRX are to be indicated at different timings, then the value of new-RNTI can be different than the existing cellDTRX-RNTI.
Proposal 3: Using a new configurable RNTI with DCI format 2_9 to indicate SSB adaptation is to be considered.
Observation 3: For L1-RSRP reporting, the SSB resource used as the reference must be within a certain time window relative to the reporting instance. The UE must measure the SSB resource within a specific time interval before the reporting trigger to ensure the measurement reflects current channel conditions.
Proposal 4: Impact of application delay to L1/L3 measurement to be considered while defining the timing constraints. 
Proposal 5: When SSB ON/OFF and SSB periodicity adaptation happens, such time restriction may or may not apply and UE behaviour in such cases may need to be addressed.
Observation 4: Overlap of additional PRACH resources and legacy PRACH resources can cause ambiguity for SSB-RO mapping in the overlapped resource in both time and frequency domains. 
Observation 5: In Case 2, for FR1, when gNB performs digital beamforming, it is possible for the gNB to apply proper receiving beam for time domain overlapped PRACH but FDMed between the additional PRACH resources for NES capable UEs and the PRACH resource for legacy UEs.
Observation 6: Case 2, for FR2, where gNB performs analog time domain beam sweeping, can cause difficulty for the gNB to receive PRACH from the two PRACH resources overlapping in time domain.
Proposal 6: Case 1 and Case 3 can be supported without any additional conditions.
Proposal 7: Case 2 may only be supported with additional conditions such as, only for FR1 or SSB-RO mapping of time domain overlapped ROs should follow one of the PRACH resources, e.g. legacy PRACH resource.
Observation 7: Condensing the ROs in time domain will allow gNB be to have longer sleep opportunities and lead to better NES gains. 
Observation 8: Condensed ROs can be achieved by confining the ROs within a configurable time window. 
Proposal 8: Configurable time window condensing ROs should be supported and should be indicated to the UEs via DCI or SIB1.
Proposal 9: The time window and PRACH configuration and adaptation parameters can be checked by the UE in SIB1 periodically (based on timer) or in an event triggered fashion. 
Observation 9: Even if DCI is checked for additional PRACH resources, SIB1 is further required to be received before random access procedure for UAC.
Proposal 10: SIB1 based mechanism should be supported i.e. the information on additional PRACH resources is in SIB1. Or UAC related information is sent in DCI and to omit SIB1 reception before random access procedure.
Observation 10: When DCI format 1_0 is used for indication of PRACH adaptation, there will be difference in operation between case of network triggered traffic and case of UE initiated traffic.
Observation 11: When network triggers traffic and DCI 1_0 with P-RNTI is received at the time of paging, UE is not required to receive any additional DCI (apart from information it received along with paging).
Observation 12: When UE has data traffic to be sent (UE initiated traffic) it must receive DCI 1_0 with P-RNTI (new paging DCI/P-RNTI) used for additional PRACH resources availability for certain period. There will be additional latency and additional UE power consumption to wake-up for reception of this DCI.
Proposal 11: To reduce latency and UE power consumption, information of PRACH adaptation in the DCI 1_0 with P-RNTI last received by the UE can still be valid. Alternatively, such adaptation information can be sent in the SIB1.
Observation 13: Once the DCI 1_0 with P-RNTI indicates the availability of additional PRACH resources, the resources are deemed to be valid as dictated by the validity time duration for availability as configured by the higher layer signaling.
Observation 14: There can be cases where the validity duration configured and sent to the UEs via higher layer signaling are longer and the network decides in between to deactivate the additional PRACH resources, since the additional PRACH resources may not be required under the given network load and circumstances.
Proposal 12: Explicit deactivation of additional PRACH resources using DCI is beneficial and needs to be considered.

3GPP TSG RAN WG1 #121		 R1-2503888
St Julian’s, Malta, May 19th – 23rd, 2025

Agenda item: 	9.5.3
Source: 	Xiaomi
Title:	Discussion on adaptation of common signal and channel transmissions
Document for:	Decision

1 

Conclusion
Based on the discussion and analyses in section 2, we have the following proposals:

Proposal 1: For adaptation of SSB in time domain, the mechanisms captured in current specification are applied to the following aspects:
The impact on DL RE mapping
The impact on UL transmission
The impact on initial access
UE’s assumption on SSB pattern
Proposal 2: For DCI format 2_9 carrying SSB periodicity adaptation indication, the number of PDCCH candidates and supported aggregation levels can be different from that of DCI format 2_9 scrambled by DTX/DRX RNTI. The following restrictions can be considered for the relevant search space configuration:
Aggregation level 4, 8 and 16 are supported.
Up to 2 PDCCH candidates are supported for each aggregation level.
Proposal 3: For adaptation of SSB in time-domain, it is applicable to an activated SCell.
Proposal 4: Confirm the following working assumption with modification.
Proposal 5: The adaptation of PRACH can be applied to CBRA and CFRA, including 4-step RACH and 2-step RACH.
Proposal 6: For the case same PRACH configuration index for additional and legacy PRACH resources, support option 1-2a with fixed N1 value.
Opt 1-2a: up to N1 additional value(s) of (x, y) 
N1 = 1
Proposal 7: For the case different PRACH configuration index for additional and legacy PRACH resources, the following option 1-5 is adopted:
Opt 1-5: No additional mechanism is selected.
Proposal 8: Only DCI format 1_0 with CRC scrambled by P-RNTI is used to carry PRACH adaptation indication.
Proposal 9: For DCI-based adaptation to indicate whether the additional PRACH resources provided by semi-static signalling are available or not, 1 bit in DCI format 1_0 with CRC scrambled by P-RNTI.
‘0’ indicates default PRACH resources are available
‘1’ indicates additional PRACH resources are available
Proposal 10: If the availability information for additional PRACH resource is introduced, the following should be adopted:
The reference time point is the first frame of the first PRACH association period after UE receives the DCI.
Proposal 11: Adopt the following text proposal on PRACH adaptation.


4 

3GPP TSG RAN WG1 #121		                                     R1-2503974 
St Julian’s, Malta, May 19th – 23th, 2025

Agenda Item:	9.3.1.5
Source:	InterDigital Inc.
Title:	Discussion on adaptation of common signal/channel transmissions
Document for:	Discussion 

Conclusion
In this contribution, the following proposals are made:
Proposal 1: Support DCI format 2_9 for adapting the SSB burst periodicity in Scenario #2 and Scenario #3B  
Proposal 2: Support the first actually transmitted SSB burst after the time gap as the first possible SSB burst upon reception of DCI format 2_9 indicating the adapted SSB periodicity
Proposal 3: A new SSB offset related to DCI-based adaptation of SSB burst periodicity is not introduced    
Proposal 4: Support reindexing the f_id in the calculation of RA-RNTI to begin with the FDMed legacy ROs followed by the FDMed additional ROs when both the legacy and additional ROs overlap in time domain 
Appendix: Agreements on adaptation of common signal/channel transmissions
RAN1#120bis Agreements

RAN1#120 Agreements

RAN1#119 Agreements

RAN1#118bis Agreeements

RAN1#118 Agreeements

RAN1#117 Agreeements

RAN1#116bis Agreeements

RAN1#116 Agreeements

3GPP TSG RAN WG1 #121	R1- 2504000
St Julian’s, Malta, May 19th – 23th, 2025	

Agenda Item:	9.5.3
Source: 	Fujitsu
Title:	Discussion on adaptation of common signal / channel transmissions
Document for:	Discussion/Decision

Conclusions
In this contribution, we discussed common signal/channel adaptation to achieve power saving for network. The following observations and proposals are provided.
Observation 1. As per the agreements reached in RAN2#129bis meeting, there is a one-to-one mapping between SSB burst periodicities and SMTC configurations.
Proposal 1. The first possible SSB burst after adaptation is determined based on the corresponding SMTC configuration. 
Proposal 2. PRACH adaptation for 2-step RACH is deprioritized.
Proposal 3. Confirm that the additional PRACH resources are configured within the same RACH-ConfigCommon as the legacy PRACH resources.
Proposal 4. Support separate configuration of totalNumberOfRA-Preambles.
Proposal 5. Support separate configuration of the following parameters for the additional PRACH resource configuration associated with feature combination.
startPreambleForThisPartition
numberOfPreamblesPerSSB-ForThisPartition
Proposal 6. The PDCCH order that indicates availability information of the additional PRACH resources can only be used to trigger PRACH transmission to the serving cell.
Observation 2. When the configuration of PRACH resources is absent in the CFRA field, CFRA shares the same ROs as those for CBRA, which are configured in RACH-ConfigCommon. 
Observation 3. Since the paging occasion for a connected mode UE to monitor within a modification period is determined by the UE itself, the NW may be unsure whether a connected mode UE has received the paging DCI or not. In this case, PDCCH order can be used to indicate the availability of the additional PRACH resources. 
Proposal 7. The PRACH resource indicator in the PDCCH order is used to indicate the current status of additional PRACH resources.
The value of ’1’ indicates that the additional PRACH resources are available from the first frame of the current modification period until the end of validity duration.
The value of ’0’ indicates that the current availability status remains unchanged.
Proposal 8. When the PDCCH order indicates additional PRACH resource(s) are available for the trigger PRACH, 
If the value of “random access preamble index” field is not all zeros, the indicated SSB index and PRACH mask index are applied to both legacy PRACH resources and additional PRACH resources.
If the PRACH mask index indicates a PRACH occasion that exists solely for additional PRACH resources or legacy PRACH resources, then it can only be applied to those specific resources.
If the value of “random access preamble index” field is all zeros, the SSB index field and PRACH mask index field are reserved, same as legacy.
Observation 4. Using DCI to deactivate the additional PRACH resources in the middle of the validity duration is beneficial for network energy saving. However, it may cause RACH failure if a UE misses the deactivation DCI and continues to transmit on the additional PRACH resources.
Proposal 9. Using DCI to explicitly deactivate the additional PRACH resources is not supported. 
Proposal 10. Support configuring one modification period as validity time duration. 
Observation 5. If the validity time duration is set to one modification period, this ensures that all the idle/inactive UEs camp on the NES cell during the periods when additional PRACH resources are available can receive the DCI indication.
Proposal 11. Remove the changes to the description of Short Message field in TS 38.212.
Observation 6. When the additional PRACH resources are configured to be FDMed with the legacy PRACH resources, the RA-RNTI issue occurs even if the UEs select different ROs, making the UEs unable to distinguish the RAR intended for them. 
Proposal 12. RAN1 to discuss how to address the RA-RNTI issue. The following approaches can be considered:
Reindex the frequency index (f_id) of additional PRACH resources by adding an offset relative to that of the legacy PRACH resources 
Introduce a new value of ul_carrier_id for additional PRACH resources. 

3GPP TSG RAN WG1 #121	R1-2504017
St Julian’s, Malta, May 19th – 23rd, 2025

Agenda Item:	9.5.3
Source:	Ericsson
Title:	Adaptation of common signal/channel transmissions for NES
Document for:	Discussion 

Conclusion
In previous sections, the following observations were made: 
Observation 1	DCI 2_9 used for adapting the SSB periodicity on an SCell (active or deactivated) can be provided on the PCell. This is useful for RRM related actions such as SCell removal or scheduling decisions.
Observation 2	Additional limitations on SSB periodicity adaptation for SCells are not required.
Observation 3	Providing the adaptation indication in DCI 1_0 with SI-RNTI and P-RNTI allows UE reselecting/camping on a cell to obtain the indication in a quicker fashion.
Observation 4	The RA-RNTI ambiguity issue occurs only for Case 2. There is no ambiguity for Case 1 and Case 3 (i.e. when additional and legacy RACH resources do not overlap in time).
Observation 5	RAN2 has already agreed that Paging adaptations are configured semi-statically and updated via system information update notification.
Observation 6	Based on the RAN2 agreement that the maximum Ns is 8, the legacy DCI 2_7 structure, which also supports Ns = 8, can be reused for Rel-19 PEI.
Observation 7	Rel-19 PEI independently addresses the additional Rel-19 POs, including those overlapping with legacy POs. Rel-19 UEs only need to decode the Rel-19 PEI, even when some Rel-19 POs overlap with legacy POs.
Observation 8	Separation of additional Rel-19 PEI transmission occasions from legacy ones can be achieved through different PEI-PO-Offset and/or pei-SearchSpace configurations, including firstPDCCH-MonitoringOccasionOfPEI-O.
Observation 9	Multiplexing legacy and Rel-19 PEIs conserves network energy by eliminating unnecessary transmissions. When feasible, legacy and Rel-19 PEI bits can be combined in the same DCI 2_7, without impacting legacy UEs.
Observation 10	Multiplexing legacy and Rel-19 PEIs through network implementation, without introducing additional parameters, requires CN subgrouping and the same po-NumPerPEI, which may limit flexibility.
Observation 11	By introducing one or two parameters, flexible multiplexing of legacy and Rel-19 PEIs can be achieved using the legacy DCI 2_7 reserved bits, without enforcing CN subgrouping or requiring the same po-NumPerPEI for legacy and/or Rel-19 UEs.

Based on the discussion in the previous sections we propose the following:
Proposal 1	For DCI 2_9-based SSB burst periodicity adaptation for an SCell, existing search space configuration parameter for DCI 2_9-based monitoring and DCI 2_9 size configuration parameter is reused.
Proposal 2	Reuse the legacy DCI 2_9 application delay in table 11.5-1 of TS 38.213 for SSB adaptation.
Proposal 3	Introduce an optional SSB offset parameter as part of the RRC configuration for each additional SSB periodicity for SSB adaptation.
	If the optional SSB offset is not configured, the SSB offset given in SCellConfig is applied for the additional SSB periodicity.
Proposal 4	Support configuration of the additional PRACH resources within the same RACH-ConfigCommon in SIB1 used to configure the legacy PRACH resources.
Proposal 5	The value range for PRACH-Config Index parameter for PRACH configuration index for additional RACH configuration is same as legacy, i.e. INTEGER (0..255).
Proposal 6	Do not support adaptation of RACH in time domain for 2-step RA in Rel-19.
Proposal 7	Regarding short messages field description in 38.212, there is no need to change the text captured in endorsed editor CR for 38.212.
Proposal 8	Supported values for validity duration configured by higher layers include {2,4,8,16, 32, 64, 128, 256} x SI modification period.
Proposal 9	Additional DCI based mechanism to explicitly deactivate PRACH resources is not needed, as a timer-based mechanism is already supported.
Proposal 10	For PDCCH order, the additional RACH resources refer to the additional RACH resources configured via SIB1 and adaptable via P-RNTI (i.e. addl-RACH-Config-Adaptation).
Proposal 11	For adaption of PRACH in time-domain, for PDCCH order (of connected mode UE),
	The new 1-bit field is used for triggering RACH based on additional RACH resources only when Random Access Preamble index" is all zeros
Proposal 12	There is no need to change Table 7.3.1.2.1-5 regarding the 1-bit field for PDCCH order in endorsed editor CR for 38.212.
Proposal 13	For the DCI-based adaptation for additional PRACH resources, also support DCI format 1_0 with CRC scrambled by SI-RNTI to carry the adaptation indication.
Proposal 14	Select one of the following alternatives for addressing RA-RNTI ambiguity issue:
	Alt a) modifying RA-RNTI equation
	Alt b) reindex the f_id for additional valid ROs by adding the value of msg1-FDM of legacy ROs when the additional valid ROs and legacy ROs overlap in time domain
	Alt c) no special handling (e.g. leave it up to implementation)
Proposal 15	For Rel-19 PEI configuration support of multiplexing of legacy and Rel-19 PEIs, ask RAN2 to additionally introduce the following optional parameters: - Starting bit position within DCI 2_7 for Rel-19 paging indication field [default 0] - Starting bit position within DCI 2_7 for TRS info
 
 

3GPP TSG RAN WG1 #121		R1-2504032
St Julian’s, Malta, May 19th – 23th, 2025

Agenda Item:	9.5.3
Source:	Google
Title:	Adaptation of Common Signals
Document for:	Discussion/Decision

Conclusion
In this contribution, we provided discussion on adaptation of common signals. Based on the discussion, the following proposals are provided.
SSB time-domain adaptation
Proposal 1: For UE-dedicated signal, the rate matching pattern should be based on the updated periodicity for the SSB.
Proposal 2: For UE-dedicated signal, the rate matching pattern should be based on the initial periodicity for the SSB configured by RRC.
Proposal 3: With regard to SSB time-domain adaptation, a valid RO that overlaps with SSB should be considered as an unavailable RO
UE transmits the PRACH on the next available valid RO

PRACH time-domain adaptation
Proposal 4: For PDCCH-ordered PRACH, when the additional PRACH resource is available, the applicable resources are based on the additional PRACH resource 
Proposal 5: For CFRA, support the NW to configure whether the UE should select the RO from additional PRACH resources for NES or legacy PRACH resources.
Proposal 6: For initial transmission of CBRA, support the UE to select the PRACH resource set based on the measured RSRP
If the measured RSRP is above a threshold, UE selects the RO from the additional PRACH resources for NES; otherwise, UE selects the RO from legacy PRACH resources
Proposal 7: For retransmission of CBRA, support the UE to select the RO either from the additional PRACH resources for NES or legacy PRACH resources
UE maintains the power ramping counter
Proposal 8: With regard to UEs that support NES only and UEs that support both SBFD and NES, support to configure two additional PRACH resource sets for NES
The first set is not applicable to the SBFD symbols/slots and the second set is applicable to the SBFD symbols/slots

PO/PEI-O adaptation
Proposal 9: Support SSB-group-specific PO/PEI-O configuration
One PO/PEI-O may include the MOs associated one group of SSBs
Proposal 10: Support dynamic update of PO/PEI-O configuration, including
Activation/deactivation of PO/PEI-O
Activation/deactivation of MOs of a PO/PEI-O

3GPP TSG RAN WG1 #121			R1-2504038
St Julian’s, Malta, May 19th – 23th, 2025

Agenda item:	9.5.3
Source:	KT Corp.
Title:	Discussion on adaptation of common signal/channel transmissions
Document for:	Discussion and decision


1. 

Conclusion
We give our proposals in this contribution as follows:

Proposal 1: When the valid RACH occasion is not clarified by the SSB period adaptation, the RACH resource is not affected by the SSB period adaptation and follows the shortest SSB periodicity.

Proposal 2: Further clarification of the PDCCH collision with adapted SSBs is not needed. 

Proposal 3: Rate-matching for PDSCH around SSB that is newly transmitted is applied from time instance A when UE receives SSB adaptation signaling to shorter period. Rate-matching for PDSCH around SSB that is not transmitted any more is not applied from time instance B when UE receives SSB adaptation signaling to longer period.

Proposal 4: UE can be configured with multiple SSBs with adaptive periodicity and indication signal contains target SSB by the manner of content or RNTI (for DCI).

Proposal 5: Both MAC-CE and DCI can be used to indicate SSB period adaptation.

Proposal 6: For a cell supporting SSB adaptation operation, support at least Option 2 and further study whether to additionally support Option 1.
Option 1: A CSI report configuration is associated with both of SSB after and before adaptation.
Option 2: A CSI report configuration is associated with one of SSB after and before adaptation.

Proposal 7: For a cell supporting SSB adaptation operation and for L1 measurement based on adaptive SSB, further study whtheer periodic, semi-persistent, or aperiodic CSI report can be supported.
Semi-persistent, or aperiodic CSI report is supported along with adaptation.
Periodic CSI report is supported for the longest SSB period.

Proposal 8: For the additional PRACH resources by adaptation, only CBRA is supported.


5. 

3GPP TSG RAN WG1 #121																R1-2504052
St Julian’s, Malta, May 19th – 23th, 2025
Agenda Item:	9.5.3
Source:	China Telecom
Title:	Discussion on common channel signal adaptation
Document for:	Discussion and decision

Conclusions
In this contribution, we discuss NES and have following observations and proposals:
Observation 1：For DCI format 2_9 indicating the SSB adaptation, only if all the cells associated with the DCI configured with SSB adaptation and Cell DTX/DRX at the same time, it is meaningful to keep the size same as using the DCI to indicate Cell DTX/DRX.
Observation 2: For the cell configured with SSB adaptation and Cell DTX/DRX at the same time, the length of each block can be different.
Proposal 1: If gNB configures both SSB adaptation and Cell DTX/DRX at the same time, the length of DCI format 2_9 should be the maximum length for indicating Cell DTX/DRX and SSB adaptation independently.
Proposal 2: If Cell DTX/DRX and SSB adaptation are configured at the same time, for the cells only support one of the functions, the corresponding configured bits can be used for indicating the function as long as they is not configured for indicating the other function regardless of the scrambled RNTI type. 
Proposal 3: The first possible SSB should be the first SSB burst with new indicated SSB periodicity after the SSB burst with current periodicity when receiving the DCI format 2_9.
Proposal 4: Support number of association pattern periods K=16 for the PRACH mask to identify the subset of the additional PRACH resources
Proposal 5: For determining the additional PRACH resources for the adaptation of PRACH in time-domain, for Alt1 (same PRACH configuration index), Opt 1-2a should be prioritized with N1=1.
Proposal 6: Support Opt 1-5, i.e., no additional mechanism adapted, for determining the additional PRACH resources for the adaptation of PRACH in time-domain, for Alt2 (different PRACH configuration index).
Proposal 7: Not support to adopting the PRACH adaptation in time-domain with both same and different configuration index at the same time.   

3GPP TSG RAN WG1 #121	 R1-2504101
St Julian’s, Malta, May 19th – 23rd, 2025

Agenda Item:	9.5.3
Source:	HONOR
Title:	Discussion on adaptation of common signal/channel transmission
Document for:	Discussion and Decision

Conclusions
In this contribution, we discuss on adaptation of common signal/channel transmission with the following proposals.
Proposal 1: The first SSB burst is the first candidate position for SSB transmission with a periodicity of 20ms after d slots.
Proposal 2: Unify the numbering of legacy frequency domain ROs and additional frequency domain ROs according to their frequency domain positions to resolve the RA-RNTI ambiguity issue.

3GPP TSG RAN WG1 #121                                          R1-2504143
St Julian’s, Malta, May 19th – 23rd, 2025
Source: 	ETRI
Title:	Adaptation of common signal/channel transmissions
Agenda Item:	9.5.3   Adaptation of common signal/channel transmissions
Document for:	Discussion/Decision

Conclusion
In this contribution, we discuss our view on potential enhancements for time domain adaptation for SSB and PRACH. The following proposals are noted.
Proposal 1: When a DCI format 2_9 indicates a SSB periodicity for an SCell, the indicated periodicity is applied to all relevant SSBs in the SCell, regardless of which DL BWP is currently active.
Proposal 2: If combined with the OD-SSB feature, the SSB periodicity adaptation can be applied only to the AO-SSB.
Proposal 3: Allow UE to switch between legacy and additional PRACH resources across the initial PRACH transmission and its retransmission.
Proposal 4: Power ramping procedure remains consistent when UE switches PRACH resources between the initial transmission and the retransmission (i.e., the power ramping counter is not reset).
Proposal 5: For a case where legacy ROs and additional ROs are FDM-ed while occupying the same set of symbols, update the RA-RNTI equation based on one of the following options:
Option 1: Reinterpret f_id such that it is mapped over legacy ROs first, followed by additional ROs.
Option 2: Reflect the PRACH configuration ID in the RA-RNTI equation.

3GPP TSG RAN WG1 #121		                        R1-2504178
St Julian’s, Malta, May 19th-23th, 2025
Source: 	Transsion Holdings
Title:	Discussion on adaptive transmission of common signal or common channel
Agenda item:	9.5.3
Document for:	Discussion & Decision

Conclusions
In this contribution, some considerations on adaptation of common signal/channel are discussed, and the following proposals are made.
Proposal 1  For the first possible SSB burst, it may have the same half-frame index and SFN index as the SSB prior to the period change.
Proposal 2  Switching the SSB burst periodicity using DCI format 2_9 can be applied to all scenarios of AI 9.5.1.
Proposal 3  TotalNumberOfRA-Preambles and NumberOfRA-PreamblesGroupA can be configured separately for the additional PRACH resources at least for 4-step RACH.
Proposal 4  DCI 1_0 with P-RNTI can be used to explicitly deactivate the additional PRACH resources. 

3GPP TSG RAN WG1 #121		R1-2504194
St Julian’s, Malta, May 19th – 23th, 2025


Source:	OPPO
Title:	Discussion on adaptation of common signal/channel transmission
Agenda Item:	9.5.3
Document for:	Discussion and Decision

Conclusion
In this contribution, we provide our views on adaptation of common signal/channel transmission for Rel-19 NES. The following proposals are provided.
Observation 1:	when network has triggered PRACH adaptation via DCI, the network normally does not 	signal the paging DCI again to trigger another PRACH adaptation during the validity time 	duration.Otherwise, it would result in an endless adaptation. If the UE camps during the 	validity time duration, the UE is not able to know the additional PRACH occasions are 	made available. 
Observation 2:	RAN1 has agreed to introduce an indication in DCI 1-0 for PDCCH order to indicate 	whether only legacy RO is used or both legacy and additional RO can be used for PRACH 	transmission. But this was not clearly reflected by RAN1 agreement. Therefore in draft 	CR, editor formulated the spec as if the PDCCH order can activate the additional ROs 	forever.
Observation 3:	When network configures additionally legacy 2-step RACH, an R19 UE would follow this 	specification to invalid a MsgA-PUSCH occasion when it is overlapped with R19 additional 	RO, leading to a different understanding on the legacy MsgA-PUSCH occasion validation 	result. 

Proposal 1:	For the configured additional PRACH, the system information should also configure a 	default status and a corresponding applicable validity time duration. 
Proposal 2:	adopt TP#1 to address this issue.
--------------------- TP#1 ------------------
Clause 8.1
--- omit unrelated text----
Valid PRACH occasions associated with addl-RACH-Config-Adaptation, and additionally associated with prach-SubsetMask-Index-Adaptation, if provided, are activated for PRACH transmission based on an indication in a DCI format 1_0 with CRC scrambled by a P-RNTI [or a C-RNTI] [5, TS 38.212]. For activation by DCI format 1_0 with CRC scrambled by the P-RNTI, the PRACH occasions are available for a duration provided by validity-DurationForAddlRACHAdaptation, starting from the first frame of the SI modification period [12, TS 38.331] that includes a PDCCH monitoring occasion where the UE receives a PDCCH providing the DCI format 1_0 with CRC scrambled by the P-RNTI. For activation by a DCI format 1_0 with CRC scrambled by the C-RNTI, the PRACH occasions are available until the UE performs the PRACH transmission triggered by the DCI. 
---- omit unrelated text ----
----------------------- end of TP#1 --------------------
Proposal 3:	RAN1 needs to adopt that the R19 additional RO is invalid when it is overlapped with 	MsgA-PUSCH occasion. 
Proposal 4:	When UE determines the candidate SSB burst location, UE assumes the first SSB burst 	corresponding to different SSB periodicity are aligned starting from SFN#0.  

3GPP TSG RAN WG1 #121			                  R1-2504249
St. Julian’s, Malta, May 19th – 23rd, 2025

Agenda Item:	9.5.3
Source: 	LG Electronics
Title: 	Adaptation of common signal/channel transmissions
Document for:	Discussion and decision

Conclusions
Proposal #1: When DCI indicates SSB adaptation from periodicity #1 to periodicity #2, consider the following options for determining the SSB time domain location for SSB with periodicity #2.
Option 1: UE expects that SSB with periodicity #2 is transmitted at the earliest of the candidate occasions for SSB with periodicity #1 after the processing time for DCI.
Option 2: UE expects that SSB with periodicity #2 is transmitted from time instance A. Time instance A is the first “possible” SSB occasion with periodicity #2 which is at least after the processing time of DCI. The time domain location such as SFN offset and half frame index of “possible” SSB with periodicity #2 should be known to UE before the UE receives DCI.
Proposal #2: RO validation before SSB-to-RO mapping is performed based on the SSB burst periodicity using legacy signalling for the SCell, as in legacy.
Proposal #3: SSB-to-RO mapping is performed based on the SSB burst periodicity using legacy signalling for the SCell, as in legacy.
Proposal #4: After SSB-to-RO mapping, if an RO is collided with an SSB (which is transmitted with SSB burst periodicity configured by addl-ssb-Periodicity) or located within  symbols after a last symbol of the SSB, UE does not transmit PRACH within the RO.
Proposal #5: If at least one RE for a PDCCH candidate overlaps with at least one RE of a candidate SSB which is transmitted with SSB burst periodicity configured by addl-ssb-Periodicity, the UE is not required to monitor the PDCCH candidate.
Proposal #6: The UE shall assume that the PRBs containing SSB transmission resources are not available for PDSCH in the OFDM symbols where SSB is transmitted with SSB burst periodicity configured by addl-ssb-Periodicity.
Proposal #7: Support the following TP for TS 38.213.

Table 8.1-0: Mapping of mask index to association periods per Kmask association pattern periods

Proposal #8: Support to keep the original wording in TS 38.212 for Short Messages provided by editor for the case when addl-PRACH-Config-Adptation is configured.
Proposal #9: For multi-cell scenario (e.g., CA/DC), the following options can be considered to indicate additional PRACH resource adaptation in connected mode UEs:
Option 1: A DCI format 1_0 scrambled by P-RNTI of PCell can be used to additional PRACH resource adaptation for other cells (e.g., PSCell/SCell). In this case, more than 1 bit payload can be required for the DCI.
Option 2: If the additional PRACH resource adaptation is indicated by DCI format 1_0 scrambled by P-RNTI in the PCell, UE can interpret that the adaptation is also applied for PSCell/SCell.
Option 3: A DCI format 2_9 can be used to additional PRACH resource adaptation for multiple cells (e.g., PSCell/SCell).
Proposal #10: RAN1 to discuss whether to support indicating both SSB burst periodicity indication and additional PRACH resource availability at once via DCI format 2_9 with ssbPeriodicityIndicationSSB-RNTI. If supported, the following options can be considered.
Option 1: Interpret as the availability of additional PRACH resource is indicated when a specific SSB burst periodicity change is indicated
Option 2: PRACH resource indicator field can be added to the field for indicating SSB burst periodicity per cell in DCI format 2_9 to indicate the availability of additional PRACH resources independently for each cell.
Proposal #11: RAN1 to discuss the following options for enhancing the RA-RNTI formula when the default RO and additional RO are configured to be FDMed in a same slot/symbol.
Option 1: Reinterpret f_id in RA-RNTI formula such that f_id of the default RO(s) starts from 0 and f_id of the additional RO(s) starts from the number of FDMed default RO(s) (i.e., msg1-FDM configured for the default RO).
Option 2: Introduce a flag bit in RA-RNTI formula where flag=0 for the default RO while flag=1 for the additional RO  
Proposal #12: RAN1 to discuss whether valid PRACH occasion in following sentence from TS 38.213 can include the additional PRACH resources which is indicated as available by the DCI
For a set of symbols of a slot corresponding to a valid PRACH occasion and Ngap symbols before the valid PRACH occasion, as described in clause 8.1, the UE does not receive PDCCH, PDSCH, or CSI-RS in the slot if a reception would overlap with any symbol from the set of symbols. The UE does not expect the set of symbols of the slot to be indicated as downlink by tdd-UL-DL-ConfigurationCommon or tdd-UL-DL-ConfigurationDedicated.
Proposal #13: When PRACH is triggered with DCI format 1_0 with C-RNTI and additional PRACH resource(s) are indicated to be available, the following options can be considered to select RO
Option 1: The UE select the closest RO (legacy RO or additional RO) after applying PRACH mask index to transmit PRACH after receiving the DCI.
Option 2: If PRACH configuration index for the additional PRACH resources is same as the legacy PRACH resources, the UE select the closest RO (legacy RO or additional RO) after applying PRACH mask index to transmit PRACH after receiving the DCI. Otherwise (i.e., different PRACH configuration index) the UE will prioritize select the additional RO.
Proposal #14: To address the issue that PEI-enabled NES UEs require to monitor both PEI and PO to check whether additional ROs are activated or not, consider the following options:
Option 1: Support indicating the additional PRACH resource adaptation using the DCI format scrambled by PEI-RNTI
Option 2: Introduce 1-bit flag in DCI format scrambled with PEI-RNTI to indicate PO monitoring for the additional PRACH resource adaptation
Proposal#15: When additional PRACH resources (i.e., NES ROs) are configured for the NES-capable UE,
Consider the following options for initial PRACH transmission attempt in one random access procedure:
Option 1: Always select NES ROs as a high priority
Option 2: Select ROs based on the per-configured priority between default ROs and NES ROs 
Consider the following alternatives for PRACH transmission re-attempt in one random access procedure
Alt 1: Always use ROs of the same type (i.e., default RO or NES RO) as the earlier PRACH transmission for the rest of the random access procedure
Alt 2: First use ROs of the same type as the earlier PRACH transmission for a certain number of times, and if certain conditions are met, then use ROs of the other type for the rest of the random access procedure
FFS: how to handle the case when first used RO is no longer available at the time the UE attempts to retransmit PRACH

3GPP TSG RAN WG1 #121			           R1-2504264
Malta, MT, May 19th – May 23rd, 2025
Agenda Item: 9.5.3
Source: MediaTek Inc.
Title: Adaptation of common signal/channel transmissions
Document for: Discussion and decision 

Conclusion

Observation 1: The time required to update the SSB measurement schedule may be longer than that needed for L1 signaling processing. Therefore, the application delay for SSB measurement adaptation should consider RAN4 requirements.

Proposal 1:  Send the LS to RAN4, requesting the appropriate application delay for SSB measurement procedure update.

Observation 2: Since the SMTC configuration is constant per intra-frequency, UEs schedule measurements uniformly. Misaligned measurement offsets from SSB adaptation complicate accurate scheduling, as shown in Figure 1.


Figure 1. Different measurement offsets caused by using DCI update the SSB periodicity.

Proposal 2: The updated SSB periodicity should maintain the same SMTC offset as the legacy SSB configuration. 


Figure 2. Maintain the same offset after updating the periodicity of SSB by DCI.

Proposal 3: For interactions between SSB adaptation and PRACH, we propose using a longer application delay to determine and update valid PRACH occasions. The longer application delay, similar to that used for SSB adaptation, provides the UE with additional time to recalculate validity of PRACH occasions.

Proposal 4: The following modification is recommended:
The spec with modification:
For SSB burst periodicity adaptation by DCI 2_9, the UE is not expected to transmit PRACH in a valid PRACH occasion if the occasion precedes a SS/PBCH block in the PRACH slot and does not start at least after a last SS/PBCH block reception symbol where  is provided in of TS 38.213 and the SS/PBCH block is the SS/PBCH block that is transmitted in response to SSB burst periodicity indication in DCI 2_9.

3GPP TSG RAN WG1 #121							 R1-2504327
St Julian’s, Malta, May 19th – 23th, 2025

Agenda item: 	9.5.3
Source: 	Apple
Title:	On adaptation of common signal/channel for NES enhancements
Document for:	Discussion/Decision
 

Conclusion
In this contribution, we discussed on the signaling and adaptation mechanisms for common SSB, PRACH and Paging for Rel-19 NES enhancements, the following proposal are made: 
SSB adaptation 
Proposal 1: UE expects SSB is transmitted according to the indicated periodicity and an offset starting from a slot after a sufficient time gap after the indication signaling, where
Alt 1: The offset can be explicitly configured, and ensures that the adapted SSB pattern falls into the smtc configuration selected for the indicated periodicity 
Alt 2: The offset is determined according to the smtc configuration, such that the adapted SSB pattern falls into the smtc configuration selected for the indicated periodicity

PRACH adaptation 
Proposal 2: Adopt the TP#1 in section 4.1 to delete the change in the Short Message field introduced in TS 38.212.
Proposal 3: When UE receives a DCI with C-RNTI to trigger PDCCH-ordered PRACH with 1-bit indicating the additional PRACH resources is available for the triggered PRACH, is is up to UE implementation to select between legacy or additional PRACH resources whichever comes first. 
Proposal 4: For the value range of the validity duration, integer values from 2 to 8 can be supported. 
Proposal 5: Support introducing an additional 1-bit indication in SIB1 to indicate whether the additional PRACH resources are available in the current Sl modification period, for UEs accessing the network to utilize the additional PRACH resources before receiving Paging DCI.
Proposal 6: Regarding the number of APs within the  APPs for the PRACH mask, discuss the following two options: 
Option 1: NW ensures that within the K_APP APPs, the number of APs can be divided by 2 or 4 or 8, according to the selected mask;
Option 2: The actual usable APPs are ceiled/floored accordingly.
Proposal 7: For RA-RNTI ambiguity issue, consider the following alternatives: 
Alt 1: Introduce a k_offset for the additional PRACH resources, i.e. RA-RNTI = 1 + s_id + 14 x t_id + 14 x 80 x f_id + 14 x 80 x8 x ul_carrier_id + 14 x 80x 8 x 2 x k_offset 
Alt 2: f_id for the additional PRACH resources is the index of the PRACH occasion in the frequency domain plus the number of FDMed legacy ROs.
FFS whether this applies only to the additional PRACH resources overlapped in time domain with legacy PRACH resources or applied to all additional PRACH resources. 

Proposal 8: Adopt TP#2 for TS38.213.

 

3GPP TSG RAN WG1 #121   		                                                                       R1-2504400 St Julian, Malta, May 19th – 23rd, 2025
Agenda item:	9.5.3
Source: 	Qualcomm Incorporated
Title: 	Adaptation of common channel transmissions
Document for:	Discussion/Decision

Conclusion
The contribution has discussed our views on adaptation of signal/channel transmissions. In particular, we make the following observations and proposals:
SSB adaptation in time domain
Observation 1: The current specifications mean that DCI adaptation of SSB periodicity is only limited to scenario 3B defined in agenda item 9.5.1. No specification change on application scenarios is necessary.
Proposal 1: The first SSB burst according to the indicated SSB burst periodicity that is no earlier than the slot  of the first serving cell is the last SSB burst according to the recent SSB burst periodicity.
Proposal 2: The working assumption on timeline of SSB burst periodicity can be confirmed as long as the value of d is the one defined for cell DTX/DRX. Furthermore, it does not preclude RAN4 to discuss additional time on top of d for SSB processing at UE.
Proposal 3: For SSB burst periodicity adaptation by DCI 2_9, the UE is not expected to transmit PRACH in a valid PRACH occasion if the occasion precedes a SS/PBCH block in the PRACH slot and does not start at least  symbols after a last SS/PBCH block reception symbol where  is provided in Table 8.1-2 of TS 38.213 and the SS/PBCH block is the SS/PBCH block that is transmitted in response to SSB burst periodicity indication in DCI 2_9.
Proposal 4: Adopt the following update to Clause 10 of TS 38.213 for PDCCH monitoring.


Proposal 5: Adopt the following update to Clause 5.1.4 of TS 38.214 for PDSCH resource mapping.


PRACH adaptation in time domain
Proposal 6: For DCI 1_0 with C-RNTI triggering PRACH transmission, support configuration of the additional PRACH resources within RACH- ConfigDedicated used to configure the legacy dedicated PRACH resources for PDCCH triggered RACH 
the legacy PRACH resources used for ‘additional RO validation before the SSB-RO mapping’ are configured in the RACH- ConfigDedicated
Proposal 7: The additional PRACH resources that overlap, even partially, in both time and frequency with the legacy ROs that are not mapped to SSBs are considered valid.
Proposal 8: Support an additional value of 1 for the parameter K (the number of association pattern periods over which the masking is defined) in addition to the agreed values {2, 4, 8}.
Proposal 9: The PRACH mask index indicated in DCI 1_0 triggering CFRA is common for both the legacy PRACH resources and the associated additional PRACH resources.
Proposal 10: The PRACH availability indication in the PDCCH order can indicate the availability of additional PRACH resources configured in the common RACH configuration for the following cases if the additional PRACH resources are not indicated as being available by DCI 1_0 with P-RNTI.
Case 1: The UE is not configured with a dedicated RACH configuration
Case 2: The UE is configured with a dedicated RACH configuration which does not include the dedicated additional PRACH resource configuration.
Proposal 11: In addition to paging DCI, consider supporting adaptation based on DCI format 2_7 for UE supporting PEI.
Proposal 12: Rel-19 UE should prioritize the transmission over the additional PRACH resources when they are indicated as available for transmission.
Proposal 13: Discuss Rel-19 UE PRACH power control when additional PRACH resources are available for transmission.
Proposal 14: To avoid RA-RNTI ambiguity when valid legacy and additional ROs overlap in time domain, consider one of the following options:
Option 1: Enhance RA-RNTI computation formula for the additional ROs.
Option 2: No change to RA-RNTI computation formula. Interpret the frequency domain index for ROs including both legacy ROs and additional ROs when they are overlapped in time.

Paging adaptation in time domain
Observation 2: The same DCI 2_7 can carry early paging indication for both legacy and additional POs by concatenating a bitmap for the additional POs to the bitmap indicated for the legacy UE including early indication of legacy POs and any TRS availability indication. 

Proposal 15: Adopt the following update to TS 38.212: 

3GPP TSG RAN WG1 #121	R1-2504468
St Julian’s, Malta, May 19th – 23rd, 2025
Source:	Sharp
Title:	Discussion on adaptation of common signal/channel transmissions
Agenda Item:	9.5.3
Document for:	Discussion and Decision

Conclusion
In this contribution, we have the following observations and proposals:
Proposal 1: Support 1-bit field in DCI 1_0 with C-RNTI used to trigger PRACH indicates:
1: NW indicates to the UE to use additional PRACH resources
The UE determines the applicable ROs for sending PRACH by applying the mask index only to the additional ROs.
0: NW indicates to the UE to use legacy PRACH resources
The UE determines the applicable ROs for sending PRACH by applying the mask index only to the legacy ROs.
Observation 1: Considering the RAN1#120 agreement “UE is not expected to be configured such that there are more than 8 FDM-ed valid ROs (legacy + additional ROs),” if f_id in the RA-RNTI calculation for RACH based on additional RO is reindexed continuously from legacy RO, it doesn’t exceed the value range on the current spec.
Proposal 2: Support reindexing f_id in the RA-RNTI calculation for RACH based on additional RO when it is overlapped with legacy RO (Option 2).
Observation 2: Considering the agreement from RAN2#129bis “not apply time-domain RACH adaptation to RACH resources for MSG1-based SI request,” preambles for other purpose can be reduced in additional PRACH resources.
Proposal 3: Support separate configuration of totalNumberOfRA-Preambles for the additional PRACH resources at least for 4-step RACH.
Proposal 4: When there is no configuration of Msg1-FDM for additional PRACH resources, the number of FDMed ROs for additional PRACH resources is indicated by Msg1-FDM for legacy PRACH resources.
Proposal 5: Adopt the following TP in section 8.1 of TS38.213

3GPP TSG RAN WG1 #121			R1-2504507
St Julian’s, Malta, May 19th – 23rd, 2025

Source:	NTT DOCOMO, INC.
Title:	Discussion on adaptation of common signal/channel transmissions
Agenda Item:	9.5.3
Document for: 	Discussion and Decision

Conclusion
In this contribution, we provided the following observations and proposals of adaptation of common signal/channel transmissions for network energy saving.
Proposal 1:
For the determination of the first [possible] SSB burst,
Support that UE does not expect that SFN-offset of SSB before and after SSB adaptation is applied is changed.
Proposal 2:
For adaptation of PRACH in time-domain, at least for 4-step RACH, at least for DCI 1_0 with P-RNTI,
we support on configuration of the additional PRACH resources within the same RACH-ConfigCommon in SIB1 used to configure the legacy PRACH resources.
Proposal 3:
For DCI format 1_0 with CRC scrambled by C-RNTI
Support additional PRACH resource availability is indicated only for CBRA (ra-preambleindex = 0)
The mask [table/configuration] to apply for additional PRACH resources is the same as discussed for the case of P-RNTI and the mask is semi-statically configured.
Proposal 4:
For the validation duration,
Support the determination of integer multiple can include 1.
Proposal 5:
For the determination of candidate value of , 
We support to have 16 or larger value for network energy saving perspectives.
Proposal 6
For indication of association periods (APs) for subset of additional PRACH resources within every K association pattern period (APP), 
We support on the last half/quarter/eight/sixteenth of the APs in K APPs.

3GPP TSG RAN WG1 #121	R1-2504547
St. Julian’s, Malta, May 19th – 23rd, 2025


Agenda item:	9.5.3
Source: 	Lenovo
Title: 	Adaptation of common signals and channels
Document for:	Discussion and decision

Conclusion
In summary, we have following observations and proposals:
Proposal 1: Consider multiple SSB transmissions (with different index) within the same slot of a half-frame to limit the time the gNB needs to transmit signals for enhanced energy saving.
Observation 1: Even though there is a mismatch between an actual SSB transmission periodicity and legacy UE’s assumption, legacy UEs would not select a SSB not being transmitted based on measurement. 
Proposal 2: Support SSB transmission with multiple SSB periodicities for multiple SSB subsets, each SSB periodicity applicable to each SSB subset. 
Proposal 3: Further discussion about application of the PRACH mask index for the additional resource can be left to RAN2.

3GPP TSG RAN WG1 Meeting #121	  R1-2504604
St Julian’s, Malta, May 19th – 23th, 2025

Agenda Item:		9.5.3
Source:		CEWiT
Title:			Discussion on adaptation of common signal and channel transmissions.
Document for:		Discussion 

Conclusion
In this contribution, we discussed the techniques required for NES and the following proposals are made, 

Proposal 1: Time domain adaptation of the continuously transmitted number of SSBs within an SSB burst is supported
Proposal 2: Support configuration of time offset per SSB burst periodicity for an Scell to determine the exact timing of the first possible SSB burst
Proposal 3: For SSB time-domain adaptation, support to consider collision handling rules between SSB and ROs.
Proposal 4: Support explicit deactivation of additional PRACH resources using DCI.
Proposal 5: Support SIB1 based adaptation in addition to DCI based adaptation to indicate the information on additional PRACH resources.

3GPP TSG-RAN WG1#121	R1-2504757
St. Julian’s, Malta, May 19-23, 2025

Agenda Item:	9.5.3
Source:	Moderator (Ericsson)
Title:	Summary#1 of AI 9.5.3 for R19 NES
Document for:	Discussion

Conclusion
There is no RAN1 consensus to support time domain adaptation for CD-SSB in Rel-19 for SCell

Agreement
For adaptation of SSB in time-domain, support the following to adapt SSB burst periodicity for an SCell
UE is configured with SSB burst periodicity using legacy signalling for the SCell 
UE is configured with X additional SSB burst periodicity for the SCell
FFS: Value of X
SSB occasions with larger periodicity are subset of the SSB occasions with shorter periodicity
FFS: Whether there is specification impact
Note: This does not impact the discussion on OD-SSB
For switching the periodicity, down-select between 
(MAC-CE) 
MAC-CE details for SSB burst periodicity adaptation is up to RAN2.
(DCI)
Alt 1-3: DCI based signalling is used

Agreement
For adaption of PRACH in time-domain, for a connected mode UE, support a 1-bit field in DCI 1_0 with C-RNTI used to trigger PRACH (i.e. PDCCH order) to indicate whether the additional PRACH resource(s) is available for the triggered PRACH. 
FFS: UE behaviour (e.g. applicable resources for PRACH mask index) when it is indicated of additional PRACH resource(s)
FFS: Details on how to reuse existing bit for the 1-bit indication

Agreement
For DCI-based adaptation for additional PRACH resources, DCI 1_0 with P-RNTI indicates the availability information for additional PRACH resource from a reference point and for a validity time duration
FFS: Validity time duration for availability is configured by higher layer signaling or predefined
FFS: Location of the reference point defined in the specification
FFS: Value/granularity of the validity time duration.
FFS: Whether DCI can be used to explicitly deactivate the additional PRACH resources

Agreement
For DCI-based adaptation for additional PRACH resources, support optional semi-static signalling of a single PRACH mask to identify the subset of the additional PRACH resources 
The mask is applicable at unit of 
Alt 1: PRACH association period 
Alt 2: PRACH association pattern period
Alt 3: SFN level
The PRACH association period is determined based on valid additional ROs only.
The mask is applied after valid RO determination and SSB-RO mapping.
Note: The existing behaviour in TS 38.213 "An association pattern period includes one or more association periods and is determined so that a pattern between PRACH occasions and SS/PBCH block indexes repeats at most every 160 msec." is not impacted due to application of the mask.
This is applicable at least for adaptation for DCI 1_0 with P-RNTI 
The DCI does not indicate PRACH mask selection
FFS: how the mask is identified 
Option 1: The PRACH mask is from a PRACH mask table
Pre-defined table with N=[4 or 8 or 16] rows
The semi-static signalling indicates a PRACH mask index 
Option 2: The PRACH mask is based on configuration parameters e.g. bitmap at SFN-level, periodic time domain window, …

Agreement
Separate configuration of Msg1-FDM for the additional PRACH resources at least for 4-step RACH is supported
UE is not expected to be configured such that there are more than 8 FDM-ed valid ROs (legacy + additional ROs)
FFS: When there is no configuration of Msg1-FDM
Separate configuration of number of SSB per RO is supported

Agreement
Study the following options for the reference point (for the availability information of additional PRACH resources indicated by DCI 1_0 with P-RNTI in a PF) for RRC idle/inactive mode UE and RRC connected mode UE, 
Option 1: SFN of the first PF from the next I-DRX cycle 
Option 2: SFN of the first PF from the current I-DRX cycle 
Option 3: From the first frame of the first PRACH association period after UE receives the DCI
Option 4: From the first frame of the current SI modification period 
Option 5: From the first frame of the next SI modification period

Agreement
For adaptation of SSB in time-domain, for adapting SSB burst periodicity for an SCell
Support group common DCI signalling for switching the SSB burst periodicity using DCI format 2_9 with [cellDTRX-RNTI]
FFS: which scenario(s) is this applicable for (e.g. as defined in 9.5.1)
Note: Above does not prevent RAN2 from designing a MAC CE based on OD-SSB feature and also used for SSB burst adaptation

RAN1#120bis
Agreement
For adaptation of PRACH in time-domain, at least for 4-step RACH, at least for DCI 1_0 with P-RNTI, 
Support configuration of the additional PRACH resources within [the same] RACH-ConfigCommon in SIB1 used to configure the legacy PRACH resources 
the legacy PRACH resources used for ‘additional RO validation before the SSB-RO mapping’ are configured in the RACH-ConfigCommon
Agreement
For DCI-based adaptation for additional PRACH resources, the following 1-bit field is used for adaptation indication in DCI format 1_0 with P-RNTI 
Use one bit from the Bits 5-8 within the Short Message field (from upper layers)
Send LS to RAN2 to confirm the use of this bit.
Above applies for cell that transmits the DCI for connected UEs and IDLE/INACTIVE mode UEs

Agreement
For DCI-based adaptation for additional PRACH resources, for the availability information of additional PRACH resources indicated by DCI 1_0 with P-RNTI 
the validity duration is configured via higher layer signalling.

Agreement
For DCI-based adaptation for additional PRACH resources, PRACH mask that identifies the subset of the additional PRACH resources is applicable at unit of
PRACH association period 
This PRACH mask applies to every [configured] K SSB RO association pattern period(s)

Agreement
For adaptation of SSB in time-domain, for DCI 2_9-based SSB burst periodicity adaptation for an SCell, 
The DCI is scrambled a new RNTI, 
Same search space and DCI size as that of cell DTX/DRX DCI if gNB configures both

Agreement
For DCI 2_9-based SSB burst periodicity adaptation for an SCell
the starting location of the information block for SSB burst periodicity indication for a SCell within the DCI format 2_9 is configured using a new RRC parameter 
the length of the information block is given by ceil(log2(1+X)), where UE is configured with X additional SSB burst periodicities for the SCell

Agreement
For adaptation of SSB in time-domain, UE can be configured with X (<=Xmax) additional SSB burst periodicities for an SCell.
Xmax=2

Agreement
Separate configuration of the following parameters for the additional PRACH resources at least for 4-step RACH is supported
CB-PreamblesPerSSB

Agreement
LS on DCI-based PRACH adaptation endorsed with the ACTION part modified compared to draft LS in R1-2503085 as follows:
ACTION: RAN1 respectfully asks RAN2 to confirm whether the use of above bit is feasible.
Final LS in R1-2503086.

Agreement
For adaptation of PRACH in time-domain, for a connected mode UE, 
One of the reserved bits of PDCCH order (DCI 1_0 with C-RNTI) is used for the new DCI field that indicates the availability of additional PRACH resources.

Working Assumption
When a UE receives in slot  on the active DL BWP of a first serving cell a PDCCH providing DCI format 2_9 that indicates a change in SSB burst periodicity of the SSB transmission on a second serving cell, the UE assumes SSB is transmitted on the second serving cell according to the indicated SSB burst periodicity from the beginning of the first slot containing the first [actually] transmitted SSB within the first [possible] SSB burst according to the indicated SSB burst periodicity that is no earlier than the slot  of the first serving cell where  is a number of slots for the SCS of the active DL BWP of the first serving cell [in Table 11.5-1 of TS 38.213].
FFS: how to determine the first [possible] SSB burst

Agreement
For DCI-based adaptation for additional PRACH resources, the PRACH mask to identify the subset of the additional PRACH resources is given by:
Option 1-2:  Semi-static signalling of a PRACH mask index and a value of K (number of association pattern periods)
For K: one from up to four candidate values {2,4,8, [1 or 16]}

Agreement
For DCI-based adaptation for additional PRACH resources, the reference point for the availability of additional PRACH resources indicated by DCI 1_0 with P-RNTI is the start of first frame of the current SI modification period where UE receives the DCI
The validity duration configured by higher layer signalling for the availability information of additional PRACH resources indicated by DCI 1_0 with P-RNTI is 
(Option 4) Multiple of SI modification period ({[1],2,[3],4,8,[],[],..})

Annex A (TPs related to PRACH Subset mask)
Below is TP from Nokia.



Proposal-12: Support the following TP for Clause 8.1 of TS 38.213, as per Editor CR available in R1-2503167.



Below is TP from Sharp.

Proposal 5: Adopt the following TP in section 8.1 of TS38.213

3GPP TSG-RAN WG1#121	R1-2504758
St. Julian’s, Malta, May 19-23, 2025

Agenda Item:	9.5.3
Source:	Moderator (Ericsson)
Title:	Summary#2 of AI 9.5.3 for R19 NES
Document for:	Discussion

Conclusion
There is no RAN1 consensus to support time domain adaptation for CD-SSB in Rel-19 for SCell

Agreement
For adaptation of SSB in time-domain, support the following to adapt SSB burst periodicity for an SCell
UE is configured with SSB burst periodicity using legacy signalling for the SCell 
UE is configured with X additional SSB burst periodicity for the SCell
FFS: Value of X
SSB occasions with larger periodicity are subset of the SSB occasions with shorter periodicity
FFS: Whether there is specification impact
Note: This does not impact the discussion on OD-SSB
For switching the periodicity, down-select between 
(MAC-CE) 
MAC-CE details for SSB burst periodicity adaptation is up to RAN2.
(DCI)
Alt 1-3: DCI based signalling is used

Agreement
For adaption of PRACH in time-domain, for a connected mode UE, support a 1-bit field in DCI 1_0 with C-RNTI used to trigger PRACH (i.e. PDCCH order) to indicate whether the additional PRACH resource(s) is available for the triggered PRACH. 
FFS: UE behaviour (e.g. applicable resources for PRACH mask index) when it is indicated of additional PRACH resource(s)
FFS: Details on how to reuse existing bit for the 1-bit indication

Agreement
For DCI-based adaptation for additional PRACH resources, DCI 1_0 with P-RNTI indicates the availability information for additional PRACH resource from a reference point and for a validity time duration
FFS: Validity time duration for availability is configured by higher layer signaling or predefined
FFS: Location of the reference point defined in the specification
FFS: Value/granularity of the validity time duration.
FFS: Whether DCI can be used to explicitly deactivate the additional PRACH resources

Agreement
For DCI-based adaptation for additional PRACH resources, support optional semi-static signalling of a single PRACH mask to identify the subset of the additional PRACH resources 
The mask is applicable at unit of 
Alt 1: PRACH association period 
Alt 2: PRACH association pattern period
Alt 3: SFN level
The PRACH association period is determined based on valid additional ROs only.
The mask is applied after valid RO determination and SSB-RO mapping.
Note: The existing behaviour in TS 38.213 "An association pattern period includes one or more association periods and is determined so that a pattern between PRACH occasions and SS/PBCH block indexes repeats at most every 160 msec." is not impacted due to application of the mask.
This is applicable at least for adaptation for DCI 1_0 with P-RNTI 
The DCI does not indicate PRACH mask selection
FFS: how the mask is identified 
Option 1: The PRACH mask is from a PRACH mask table
Pre-defined table with N=[4 or 8 or 16] rows
The semi-static signalling indicates a PRACH mask index 
Option 2: The PRACH mask is based on configuration parameters e.g. bitmap at SFN-level, periodic time domain window, …

Agreement
Separate configuration of Msg1-FDM for the additional PRACH resources at least for 4-step RACH is supported
UE is not expected to be configured such that there are more than 8 FDM-ed valid ROs (legacy + additional ROs)
FFS: When there is no configuration of Msg1-FDM
Separate configuration of number of SSB per RO is supported

Agreement
Study the following options for the reference point (for the availability information of additional PRACH resources indicated by DCI 1_0 with P-RNTI in a PF) for RRC idle/inactive mode UE and RRC connected mode UE, 
Option 1: SFN of the first PF from the next I-DRX cycle 
Option 2: SFN of the first PF from the current I-DRX cycle 
Option 3: From the first frame of the first PRACH association period after UE receives the DCI
Option 4: From the first frame of the current SI modification period 
Option 5: From the first frame of the next SI modification period

Agreement
For adaptation of SSB in time-domain, for adapting SSB burst periodicity for an SCell
Support group common DCI signalling for switching the SSB burst periodicity using DCI format 2_9 with [cellDTRX-RNTI]
FFS: which scenario(s) is this applicable for (e.g. as defined in 9.5.1)
Note: Above does not prevent RAN2 from designing a MAC CE based on OD-SSB feature and also used for SSB burst adaptation

RAN1#120bis
Agreement
For adaptation of PRACH in time-domain, at least for 4-step RACH, at least for DCI 1_0 with P-RNTI, 
Support configuration of the additional PRACH resources within [the same] RACH-ConfigCommon in SIB1 used to configure the legacy PRACH resources 
the legacy PRACH resources used for ‘additional RO validation before the SSB-RO mapping’ are configured in the RACH-ConfigCommon
Agreement
For DCI-based adaptation for additional PRACH resources, the following 1-bit field is used for adaptation indication in DCI format 1_0 with P-RNTI 
Use one bit from the Bits 5-8 within the Short Message field (from upper layers)
Send LS to RAN2 to confirm the use of this bit.
Above applies for cell that transmits the DCI for connected UEs and IDLE/INACTIVE mode UEs

Agreement
For DCI-based adaptation for additional PRACH resources, for the availability information of additional PRACH resources indicated by DCI 1_0 with P-RNTI 
the validity duration is configured via higher layer signalling.

Agreement
For DCI-based adaptation for additional PRACH resources, PRACH mask that identifies the subset of the additional PRACH resources is applicable at unit of
PRACH association period 
This PRACH mask applies to every [configured] K SSB RO association pattern period(s)

Agreement
For adaptation of SSB in time-domain, for DCI 2_9-based SSB burst periodicity adaptation for an SCell, 
The DCI is scrambled a new RNTI, 
Same search space and DCI size as that of cell DTX/DRX DCI if gNB configures both

Agreement
For DCI 2_9-based SSB burst periodicity adaptation for an SCell
the starting location of the information block for SSB burst periodicity indication for a SCell within the DCI format 2_9 is configured using a new RRC parameter 
the length of the information block is given by ceil(log2(1+X)), where UE is configured with X additional SSB burst periodicities for the SCell

Agreement
For adaptation of SSB in time-domain, UE can be configured with X (<=Xmax) additional SSB burst periodicities for an SCell.
Xmax=2

Agreement
Separate configuration of the following parameters for the additional PRACH resources at least for 4-step RACH is supported
CB-PreamblesPerSSB

Agreement
LS on DCI-based PRACH adaptation endorsed with the ACTION part modified compared to draft LS in R1-2503085 as follows:
ACTION: RAN1 respectfully asks RAN2 to confirm whether the use of above bit is feasible.
Final LS in R1-2503086.

Agreement
For adaptation of PRACH in time-domain, for a connected mode UE, 
One of the reserved bits of PDCCH order (DCI 1_0 with C-RNTI) is used for the new DCI field that indicates the availability of additional PRACH resources.

Working Assumption
When a UE receives in slot  on the active DL BWP of a first serving cell a PDCCH providing DCI format 2_9 that indicates a change in SSB burst periodicity of the SSB transmission on a second serving cell, the UE assumes SSB is transmitted on the second serving cell according to the indicated SSB burst periodicity from the beginning of the first slot containing the first [actually] transmitted SSB within the first [possible] SSB burst according to the indicated SSB burst periodicity that is no earlier than the slot  of the first serving cell where  is a number of slots for the SCS of the active DL BWP of the first serving cell [in Table 11.5-1 of TS 38.213].
FFS: how to determine the first [possible] SSB burst

Agreement
For DCI-based adaptation for additional PRACH resources, the PRACH mask to identify the subset of the additional PRACH resources is given by:
Option 1-2:  Semi-static signalling of a PRACH mask index and a value of K (number of association pattern periods)
For K: one from up to four candidate values {2,4,8, [1 or 16]}

Agreement
For DCI-based adaptation for additional PRACH resources, the reference point for the availability of additional PRACH resources indicated by DCI 1_0 with P-RNTI is the start of first frame of the current SI modification period where UE receives the DCI
The validity duration configured by higher layer signalling for the availability information of additional PRACH resources indicated by DCI 1_0 with P-RNTI is 
(Option 4) Multiple of SI modification period ({[1],2,[3],4,8,[],[],..})

Annex A (TPs related to PRACH Subset mask)
Below is TP from Nokia.



Proposal-12: Support the following TP for Clause 8.1 of TS 38.213, as per Editor CR available in R1-2503167.



Below is TP from Sharp.

Proposal 5: Adopt the following TP in section 8.1 of TS38.213

3GPP TSG-RAN WG1#121	R1-2504890
St. Julian’s, Malta, May 19-23, 2025

Agenda Item:	9.5.3
Source:	Moderator (Ericsson)
Title:	Summary#3 of AI 9.5.3 for R19 NES
Document for:	Discussion

Conclusion
There is no RAN1 consensus to support time domain adaptation for CD-SSB in Rel-19 for SCell

Agreement
For adaptation of SSB in time-domain, support the following to adapt SSB burst periodicity for an SCell
UE is configured with SSB burst periodicity using legacy signalling for the SCell 
UE is configured with X additional SSB burst periodicity for the SCell
FFS: Value of X
SSB occasions with larger periodicity are subset of the SSB occasions with shorter periodicity
FFS: Whether there is specification impact
Note: This does not impact the discussion on OD-SSB
For switching the periodicity, down-select between 
(MAC-CE) 
MAC-CE details for SSB burst periodicity adaptation is up to RAN2.
(DCI)
Alt 1-3: DCI based signalling is used

Agreement
For adaption of PRACH in time-domain, for a connected mode UE, support a 1-bit field in DCI 1_0 with C-RNTI used to trigger PRACH (i.e. PDCCH order) to indicate whether the additional PRACH resource(s) is available for the triggered PRACH. 
FFS: UE behaviour (e.g. applicable resources for PRACH mask index) when it is indicated of additional PRACH resource(s)
FFS: Details on how to reuse existing bit for the 1-bit indication

Agreement
For DCI-based adaptation for additional PRACH resources, DCI 1_0 with P-RNTI indicates the availability information for additional PRACH resource from a reference point and for a validity time duration
FFS: Validity time duration for availability is configured by higher layer signaling or predefined
FFS: Location of the reference point defined in the specification
FFS: Value/granularity of the validity time duration.
FFS: Whether DCI can be used to explicitly deactivate the additional PRACH resources

Agreement
For DCI-based adaptation for additional PRACH resources, support optional semi-static signalling of a single PRACH mask to identify the subset of the additional PRACH resources 
The mask is applicable at unit of 
Alt 1: PRACH association period 
Alt 2: PRACH association pattern period
Alt 3: SFN level
The PRACH association period is determined based on valid additional ROs only.
The mask is applied after valid RO determination and SSB-RO mapping.
Note: The existing behaviour in TS 38.213 "An association pattern period includes one or more association periods and is determined so that a pattern between PRACH occasions and SS/PBCH block indexes repeats at most every 160 msec." is not impacted due to application of the mask.
This is applicable at least for adaptation for DCI 1_0 with P-RNTI 
The DCI does not indicate PRACH mask selection
FFS: how the mask is identified 
Option 1: The PRACH mask is from a PRACH mask table
Pre-defined table with N=[4 or 8 or 16] rows
The semi-static signalling indicates a PRACH mask index 
Option 2: The PRACH mask is based on configuration parameters e.g. bitmap at SFN-level, periodic time domain window, …

Agreement
Separate configuration of Msg1-FDM for the additional PRACH resources at least for 4-step RACH is supported
UE is not expected to be configured such that there are more than 8 FDM-ed valid ROs (legacy + additional ROs)
FFS: When there is no configuration of Msg1-FDM
Separate configuration of number of SSB per RO is supported

Agreement
Study the following options for the reference point (for the availability information of additional PRACH resources indicated by DCI 1_0 with P-RNTI in a PF) for RRC idle/inactive mode UE and RRC connected mode UE, 
Option 1: SFN of the first PF from the next I-DRX cycle 
Option 2: SFN of the first PF from the current I-DRX cycle 
Option 3: From the first frame of the first PRACH association period after UE receives the DCI
Option 4: From the first frame of the current SI modification period 
Option 5: From the first frame of the next SI modification period

Agreement
For adaptation of SSB in time-domain, for adapting SSB burst periodicity for an SCell
Support group common DCI signalling for switching the SSB burst periodicity using DCI format 2_9 with [cellDTRX-RNTI]
FFS: which scenario(s) is this applicable for (e.g. as defined in 9.5.1)
Note: Above does not prevent RAN2 from designing a MAC CE based on OD-SSB feature and also used for SSB burst adaptation

RAN1#120bis
Agreement
For adaptation of PRACH in time-domain, at least for 4-step RACH, at least for DCI 1_0 with P-RNTI, 
Support configuration of the additional PRACH resources within [the same] RACH-ConfigCommon in SIB1 used to configure the legacy PRACH resources 
the legacy PRACH resources used for ‘additional RO validation before the SSB-RO mapping’ are configured in the RACH-ConfigCommon
Agreement
For DCI-based adaptation for additional PRACH resources, the following 1-bit field is used for adaptation indication in DCI format 1_0 with P-RNTI 
Use one bit from the Bits 5-8 within the Short Message field (from upper layers)
Send LS to RAN2 to confirm the use of this bit.
Above applies for cell that transmits the DCI for connected UEs and IDLE/INACTIVE mode UEs

Agreement
For DCI-based adaptation for additional PRACH resources, for the availability information of additional PRACH resources indicated by DCI 1_0 with P-RNTI 
the validity duration is configured via higher layer signalling.

Agreement
For DCI-based adaptation for additional PRACH resources, PRACH mask that identifies the subset of the additional PRACH resources is applicable at unit of
PRACH association period 
This PRACH mask applies to every [configured] K SSB RO association pattern period(s)

Agreement
For adaptation of SSB in time-domain, for DCI 2_9-based SSB burst periodicity adaptation for an SCell, 
The DCI is scrambled a new RNTI, 
Same search space and DCI size as that of cell DTX/DRX DCI if gNB configures both

Agreement
For DCI 2_9-based SSB burst periodicity adaptation for an SCell
the starting location of the information block for SSB burst periodicity indication for a SCell within the DCI format 2_9 is configured using a new RRC parameter 
the length of the information block is given by ceil(log2(1+X)), where UE is configured with X additional SSB burst periodicities for the SCell

Agreement
For adaptation of SSB in time-domain, UE can be configured with X (<=Xmax) additional SSB burst periodicities for an SCell.
Xmax=2

Agreement
Separate configuration of the following parameters for the additional PRACH resources at least for 4-step RACH is supported
CB-PreamblesPerSSB

Agreement
LS on DCI-based PRACH adaptation endorsed with the ACTION part modified compared to draft LS in R1-2503085 as follows:
ACTION: RAN1 respectfully asks RAN2 to confirm whether the use of above bit is feasible.
Final LS in R1-2503086.

Agreement
For adaptation of PRACH in time-domain, for a connected mode UE, 
One of the reserved bits of PDCCH order (DCI 1_0 with C-RNTI) is used for the new DCI field that indicates the availability of additional PRACH resources.

Working Assumption
When a UE receives in slot  on the active DL BWP of a first serving cell a PDCCH providing DCI format 2_9 that indicates a change in SSB burst periodicity of the SSB transmission on a second serving cell, the UE assumes SSB is transmitted on the second serving cell according to the indicated SSB burst periodicity from the beginning of the first slot containing the first [actually] transmitted SSB within the first [possible] SSB burst according to the indicated SSB burst periodicity that is no earlier than the slot  of the first serving cell where  is a number of slots for the SCS of the active DL BWP of the first serving cell [in Table 11.5-1 of TS 38.213].
FFS: how to determine the first [possible] SSB burst

Agreement
For DCI-based adaptation for additional PRACH resources, the PRACH mask to identify the subset of the additional PRACH resources is given by:
Option 1-2:  Semi-static signalling of a PRACH mask index and a value of K (number of association pattern periods)
For K: one from up to four candidate values {2,4,8, [1 or 16]}

Agreement
For DCI-based adaptation for additional PRACH resources, the reference point for the availability of additional PRACH resources indicated by DCI 1_0 with P-RNTI is the start of first frame of the current SI modification period where UE receives the DCI
The validity duration configured by higher layer signalling for the availability information of additional PRACH resources indicated by DCI 1_0 with P-RNTI is 
(Option 4) Multiple of SI modification period ({[1],2,[3],4,8,[],[],..})

Annex A (TPs related to PRACH Subset mask)
Below is TP from Nokia.



Proposal-12: Support the following TP for Clause 8.1 of TS 38.213, as per Editor CR available in R1-2503167.



Below is TP from Sharp.

Proposal 5: Adopt the following TP in section 8.1 of TS38.213

3GPP TSG-RAN WG1#121	R1-2504937
St. Julian’s, Malta, May 19-23, 2025

Agenda Item:	9.5.3
Source:	Moderator (Ericsson)
Title:	Final Summary of AI 9.5.3 for R19 NES
Document for:	Discussion

Conclusion
There is no RAN1 consensus to support time domain adaptation for CD-SSB in Rel-19 for SCell

Agreement
For adaptation of SSB in time-domain, support the following to adapt SSB burst periodicity for an SCell
UE is configured with SSB burst periodicity using legacy signalling for the SCell 
UE is configured with X additional SSB burst periodicity for the SCell
FFS: Value of X
SSB occasions with larger periodicity are subset of the SSB occasions with shorter periodicity
FFS: Whether there is specification impact
Note: This does not impact the discussion on OD-SSB
For switching the periodicity, down-select between 
(MAC-CE) 
MAC-CE details for SSB burst periodicity adaptation is up to RAN2.
(DCI)
Alt 1-3: DCI based signalling is used

Agreement
For adaption of PRACH in time-domain, for a connected mode UE, support a 1-bit field in DCI 1_0 with C-RNTI used to trigger PRACH (i.e. PDCCH order) to indicate whether the additional PRACH resource(s) is available for the triggered PRACH. 
FFS: UE behaviour (e.g. applicable resources for PRACH mask index) when it is indicated of additional PRACH resource(s)
FFS: Details on how to reuse existing bit for the 1-bit indication

Agreement
For DCI-based adaptation for additional PRACH resources, DCI 1_0 with P-RNTI indicates the availability information for additional PRACH resource from a reference point and for a validity time duration
FFS: Validity time duration for availability is configured by higher layer signaling or predefined
FFS: Location of the reference point defined in the specification
FFS: Value/granularity of the validity time duration.
FFS: Whether DCI can be used to explicitly deactivate the additional PRACH resources

Agreement
For DCI-based adaptation for additional PRACH resources, support optional semi-static signalling of a single PRACH mask to identify the subset of the additional PRACH resources 
The mask is applicable at unit of 
Alt 1: PRACH association period 
Alt 2: PRACH association pattern period
Alt 3: SFN level
The PRACH association period is determined based on valid additional ROs only.
The mask is applied after valid RO determination and SSB-RO mapping.
Note: The existing behaviour in TS 38.213 "An association pattern period includes one or more association periods and is determined so that a pattern between PRACH occasions and SS/PBCH block indexes repeats at most every 160 msec." is not impacted due to application of the mask.
This is applicable at least for adaptation for DCI 1_0 with P-RNTI 
The DCI does not indicate PRACH mask selection
FFS: how the mask is identified 
Option 1: The PRACH mask is from a PRACH mask table
Pre-defined table with N=[4 or 8 or 16] rows
The semi-static signalling indicates a PRACH mask index 
Option 2: The PRACH mask is based on configuration parameters e.g. bitmap at SFN-level, periodic time domain window, …

Agreement
Separate configuration of Msg1-FDM for the additional PRACH resources at least for 4-step RACH is supported
UE is not expected to be configured such that there are more than 8 FDM-ed valid ROs (legacy + additional ROs)
FFS: When there is no configuration of Msg1-FDM
Separate configuration of number of SSB per RO is supported

Agreement
Study the following options for the reference point (for the availability information of additional PRACH resources indicated by DCI 1_0 with P-RNTI in a PF) for RRC idle/inactive mode UE and RRC connected mode UE, 
Option 1: SFN of the first PF from the next I-DRX cycle 
Option 2: SFN of the first PF from the current I-DRX cycle 
Option 3: From the first frame of the first PRACH association period after UE receives the DCI
Option 4: From the first frame of the current SI modification period 
Option 5: From the first frame of the next SI modification period

Agreement
For adaptation of SSB in time-domain, for adapting SSB burst periodicity for an SCell
Support group common DCI signalling for switching the SSB burst periodicity using DCI format 2_9 with [cellDTRX-RNTI]
FFS: which scenario(s) is this applicable for (e.g. as defined in 9.5.1)
Note: Above does not prevent RAN2 from designing a MAC CE based on OD-SSB feature and also used for SSB burst adaptation

RAN1#120bis
Agreement
For adaptation of PRACH in time-domain, at least for 4-step RACH, at least for DCI 1_0 with P-RNTI, 
Support configuration of the additional PRACH resources within [the same] RACH-ConfigCommon in SIB1 used to configure the legacy PRACH resources 
the legacy PRACH resources used for ‘additional RO validation before the SSB-RO mapping’ are configured in the RACH-ConfigCommon
Agreement
For DCI-based adaptation for additional PRACH resources, the following 1-bit field is used for adaptation indication in DCI format 1_0 with P-RNTI 
Use one bit from the Bits 5-8 within the Short Message field (from upper layers)
Send LS to RAN2 to confirm the use of this bit.
Above applies for cell that transmits the DCI for connected UEs and IDLE/INACTIVE mode UEs

Agreement
For DCI-based adaptation for additional PRACH resources, for the availability information of additional PRACH resources indicated by DCI 1_0 with P-RNTI 
the validity duration is configured via higher layer signalling.

Agreement
For DCI-based adaptation for additional PRACH resources, PRACH mask that identifies the subset of the additional PRACH resources is applicable at unit of
PRACH association period 
This PRACH mask applies to every [configured] K SSB RO association pattern period(s)

Agreement
For adaptation of SSB in time-domain, for DCI 2_9-based SSB burst periodicity adaptation for an SCell, 
The DCI is scrambled a new RNTI, 
Same search space and DCI size as that of cell DTX/DRX DCI if gNB configures both

Agreement
For DCI 2_9-based SSB burst periodicity adaptation for an SCell
the starting location of the information block for SSB burst periodicity indication for a SCell within the DCI format 2_9 is configured using a new RRC parameter 
the length of the information block is given by ceil(log2(1+X)), where UE is configured with X additional SSB burst periodicities for the SCell

Agreement
For adaptation of SSB in time-domain, UE can be configured with X (<=Xmax) additional SSB burst periodicities for an SCell.
Xmax=2

Agreement
Separate configuration of the following parameters for the additional PRACH resources at least for 4-step RACH is supported
CB-PreamblesPerSSB

Agreement
LS on DCI-based PRACH adaptation endorsed with the ACTION part modified compared to draft LS in R1-2503085 as follows:
ACTION: RAN1 respectfully asks RAN2 to confirm whether the use of above bit is feasible.
Final LS in R1-2503086.

Agreement
For adaptation of PRACH in time-domain, for a connected mode UE, 
One of the reserved bits of PDCCH order (DCI 1_0 with C-RNTI) is used for the new DCI field that indicates the availability of additional PRACH resources.

Working Assumption
When a UE receives in slot  on the active DL BWP of a first serving cell a PDCCH providing DCI format 2_9 that indicates a change in SSB burst periodicity of the SSB transmission on a second serving cell, the UE assumes SSB is transmitted on the second serving cell according to the indicated SSB burst periodicity from the beginning of the first slot containing the first [actually] transmitted SSB within the first [possible] SSB burst according to the indicated SSB burst periodicity that is no earlier than the slot  of the first serving cell where  is a number of slots for the SCS of the active DL BWP of the first serving cell [in Table 11.5-1 of TS 38.213].
FFS: how to determine the first [possible] SSB burst

Agreement
For DCI-based adaptation for additional PRACH resources, the PRACH mask to identify the subset of the additional PRACH resources is given by:
Option 1-2:  Semi-static signalling of a PRACH mask index and a value of K (number of association pattern periods)
For K: one from up to four candidate values {2,4,8, [1 or 16]}

Agreement
For DCI-based adaptation for additional PRACH resources, the reference point for the availability of additional PRACH resources indicated by DCI 1_0 with P-RNTI is the start of first frame of the current SI modification period where UE receives the DCI
The validity duration configured by higher layer signalling for the availability information of additional PRACH resources indicated by DCI 1_0 with P-RNTI is 
(Option 4) Multiple of SI modification period ({[1],2,[3],4,8,[],[],..})

Annex A (TPs related to PRACH Subset mask)
Below is TP from Nokia.



Proposal-12: Support the following TP for Clause 8.1 of TS 38.213, as per Editor CR available in R1-2503167.



Below is TP from Sharp.

Proposal 5: Adopt the following TP in section 8.1 of TS38.213