Mobility Enhancement Rel-18

 RAN1#110-bis-e

9.12   Further NR mobility enhancements

Please refer to RP-222332 for detailed scope of the WI on further NR mobility enhancements.

 

R1-2210695        Session notes for 9.12 (Further NR mobility enhancements)              Ad-Hoc Chair (CMCC)

 

R1-2210265        RAN1 Work Plan for Rel-18 Further NR Mobility Enhancements WI               MediaTek Inc., Apple

9.12.1     L1 enhancements for inter-cell beam management

Including L1 measurement and reporting, beam indication, and dynamic switch mechanism among candidate serving cells (including SpCell and SCell).

 

R1-2208679        L1 enhancements to inter-cell beam management  Ericsson

·         Proposal 1         RAN1 develops beam indication and beam measurement for L1/L2 mobility that is independent of inter-cell beam management.

·         Proposal 2         Further consider if L1/L2 mobility should be designed for a specific TCI framework.

·         Proposal 3         The beam indication for L1/L2 mobility does not rely on RRC configuration of target TCI states.

·         Proposal 4         The beam indication can contain a QCL source for subsequent DL receptions.

·         Proposal 5         The beam indication contains a TA value for the target cell.

·         Proposal 6         The beam indication contains ID if the active DL and UL BWPs for the target cells.

·         Proposal 7         The L1/L2 mobility beam indication is carried by MAC CE.

·         Proposal 8         The beam measurement reports to assist L1/L2 mobility include measurement information on serving  and target cells.

·         Proposal 9         The beam measurements for L1/L2 mobility should require only a minimum of configuration.

·         Proposal 10       The configuration of beam measurements for L1/L2 mobility should not require that the NW specifies which PCIs should be measured.

·         Proposal 11       The beam reporting for L1/L2 mobility is performed over MAC.

·         Proposal 12       Study simplified event-driven reporting to assist L1/L2 mobility over MAC.

·         Proposal 13       The intra-frequency measurements used for L1/L2 mobility have the same requirements as the intra-frequency measurements.

·         Proposal 14       The inter-frequency measurements used for L1/L2 mobility have the same requirements as the inter-frequency measurements.

·         Proposal 15       Send an LS to RAN4 describing the accuracy requirements for the measurements used for L1/L2 mobility.

·         Proposal 16       The UE can be configured to store the QCL properties of a subset of the RSs it has reported for a limited period.

Decision: The document is noted.

 

R1-2209923        Discussion on L1 enhancements for inter-cell mobility         NTT DOCOMO, INC.

·        Proposal 1: For candidate cells on the same frequency as serving cell, the dynamic beam indication from those candidate cells used in Rel-17 ICBM can be also supported in Rel-18 L1/L2 inter-cell mobility.

·        Proposal 2: Study enhancement to support inter-frequency L1 beam measurement/reporting.

·        Proposal 3: Study event triggered L1 beam measurement/reporting.

·        Proposal 4: Study filtered L1 cell/beam/beam-group measurement/reporting and its interaction with legacy L3 measurement/reporting.

·        Proposal 5: New L1/L2 signaling is needed to indicate cell switch for Rel-18 L1/L2 inter-cell mobility. DCI based indication is preferred.

o   Support both single cell switch and cell group switch.

o   At least the cell/cell group ID of target cell/cell group should be indicated.

·        Proposal 6: For beam indication of target cell, beam indication method in Rel-17 ICBM is starting point.

Decision: The document is noted.

 

R1-2208406         L1 enhancements for inter-cell beam management      Huawei, HiSilicon

R1-2208500         Discussion on L1 enhancements for L1/L2-based inter-cell mobility      Nokia, Nokia Shanghai Bell

R1-2208509         L1 enhancements for inter-cell beam management      ZTE

R1-2208570         Discussion on L1 enhancements for inter-cell beam management           Spreadtrum Communications

R1-2208664         Discussion on L1 enhancements for L1/L2 mobility   vivo

R1-2208747         L1 enhancements for inter-cell beam management      Lenovo

R1-2208805         Discussions on Inter-cell beam management enhancement       OPPO

R1-2208884         On Intercell beam management enhancement for NR mobility enhancement               Google

R1-2208905         Enhancements on inter-cell beam management for mobility     LG Electronics

R1-2208958         On L1 enhancements for inter-cell beam management CATT

R1-2209024         Views on L1 enhancements for inter-cell beam management    Fujitsu

R1-2209073         L1 Enhancements for Inter-cell Beam Management   Intel Corporation

R1-2209203         L1 enhancements for inter-cell beam management      InterDigital, Inc.

R1-2209268         Discussion on L1 enhancements and Dynamic switch mechanism          xiaomi

R1-2209359         Discussion on L1 enhancements for inter-cell beam management           CMCC

R1-2209428         Discussion on L1 enhancements for inter-cell beam management           NEC

R1-2209498         L1 enhancements for inter-cell beam management      MediaTek Inc.

R1-2209603         On L1 enhancements for inter-cell mobility  Apple

R1-2209754         On L1 enhancements for inter-cell beam management Samsung

R1-2210008         L1 Enhancements for Inter-Cell Beam Management   Qualcomm Incorporated

 

[110bis-e-R18-Mobility-01] – Yosuke (Fujitsu)

Email discussion on L1 enhancements for inter-cell beam management by October 19

-        Check points: October 14, October 19

R1-2210414        FL summary 1 on L1 enhancements for inter-cell beam management               Moderator (Fujitsu)

From Oct 12th GTW session

Agreement

·        For Rel-18 L1/L2 mobility, L1 intra-frequency measurement for candidate cell is supported

o   At least the following aspects are for RAN1 further study:

§  RAN1 assumes Rel-17 ICBM CSI measurement as starting point.

§  Whether and how to apply relaxation for the restrictions imposed on the Rel-17 intra-frequency L1 non-serving cell measurement defined in 9.13.2 of TS38.133, where RAN4 impact is foreseen, e.g.

·        SFN offset alignment compared with serving cell

·        BWP setting, i.e. non-serving cell SSB should be covered by serving cell active BWP

·        Introduction of symbol level gap or SMTC for larger Rx timing difference (i.e. larger than CP length)

§  Commonality with intra-frequency L3 measurement

§  Commonality with L1 inter-frequency measurement for measurement configuration

·        Send an LS to RAN4 (CC RAN2)

o   RAN1 to ask RAN4 if the restriction on e.g., SFN offset alignment, BWP setting and Rx timing difference, etc, described in 9.13.2 of TS38.133 for intra-frequency L1 non-serving measurement can be relaxed or not.

o   RAN1 assumes Rel-17 ICBM CSI measurement as starting point.

Agreement

·        For Rel-18 L1/L2 mobility,

o   SSB is supported for L1 intra-frequency measurement

o   SSB is supported for L1 inter-frequency measurement if inter-frequency L1 measurements are supported

·        Further study the following L1 measurement RS for candidate cell

o   CSI-RS for tracking, beam management, CSI and mobility, CSI-IM, which is for L1 intra-frequency and L1 inter-frequency (if supported)

Agreement

·        For candidate cell measurement for Rel-18 L1/L2 mobility,

o   L1-RSRP is supported for intra-frequency candidate cell measurement.

o   Further study the following measurement quantities for candidate cell measurement

§  L1-RSRP for inter-frequency (if supported)

§  L1-SINR for intra-frequency and inter-frequency (if supported)

·        FFS: to assess the use case and the benefit of UL measurement instead of/in addition to DL L1 measurement, which includes:

o   How the UL measurement result is used, e.g. handover decision

o   Signals/channels used for UL measurement, e.g. SRS

o   Spec impact including other WGs, e.g. definition of gNB measurement, interface to transfer RS configuration or measurement results

o   Note: The next discussion will take place based on companies’ contribution in future meeting.

 

R1-2210612        FL summary 2 on L1 enhancements for inter-cell beam management               Moderator (Fujitsu)

From Oct 17th GTW session

Agreement

Agreement

Agreement

RAN1 to further study if the beam indication of candidate cell(s) L1/L2 mobility should be designed for a specific TCI framework below, and their potential RAN1 spec impact.

·        Option A:  Beam indication for Rel-18 L1/L2 mobility is designed based on Rel-17 TCI framework mechanism

·        Option B: Beam indication for Rel-18 L1/L2 mobility is designed based on Rel-15 TCI framework mechanism

·        Option C: Beam indication for Rel-18 L1/L2 mobility is designed based on both Rel-15 and Rel-17 TCI framework mechanisms

 

R1-2210675        FL summary 3 on L1 enhancements for inter-cell beam management               Moderator (Fujitsu)

Agreement

Send an LS to RAN2/RAN3 asking the clarification on intra-/inter-DU scenario:

·        RAN1 has started the discussion on the configuration for L1 measurement and TCI states for candidate cells. Regarding the following RAN2 agreements captured in RAN2 LS (R1-2208331/R2-2209257), it is not clear for RAN1 which kind of information/configuration for candidate cell(s) are available at a serving cell for inter-DU case for Rel-18 L1/L2 mobility. Thus, companies have different understanding on the implication of the sentence “as much commonality as reasonable” in the LS.

o   The design for intra-DU and inter-DU L1/L2-based mobility should share as much commonality as reasonable. FFS which aspects need to be different.

·        RAN1 respectfully asks RAN2 and RAN3 if the serving DU knows the measurement RS configuration and TCI state configuration of cells served by another DU.

Agreement

Send an LS to RAN2, 3 and 4 to inform them of the agreements under A.I 9.12.1 and A.I. 9.12.2.

If the LS related proposal under A.I 9.12.1 and 9.12.2 are agreed, the contents are also included.

(See post meeting email discussion)

 

 

Decision: As per email decision posted on Oct 20th,

Agreement

From RAN1 perspective, the following scenarios can be considered for Rel-18 L1/L2 mobility for beam indication timing. This will be updated depending on further RAN1 assessment and RAN2 decision on the time chart

·        Scenario 1: Beam indication before cell switch command

·        Scenario 2: Beam indication together with cell switch command

·       Scenario 3: Beam indication after cell switch command

Interested companies are encouraged to further study the validity of the scenarios and the potential spec impact.

 

Agreement

Interested companies are encouraged to perform technical analysis of the cell switch command from a RAN1 point of view, e.g.

·        Necessary information included in the command, which is relevant for RAN1 discussion

·        Necessary number of bits for the information

·        L1 impact or concern to use DCI or MAC CE for L1/L2 cell switch command

Agreement

RAN1 to further study the potential RAN1 enhancements and spec impact to perform at least the following procedures prior to the reception of L1/L2 cell switch command aiming at the reduction of handover delay / interruption

·        DL synchronization for candidate cell(s)

·        TRS tracking for candidate cell(s)

·        CSI acquisition for candidate cell(s)

·        Activation/Selection of TCI states for candidate cell(s), if feasible

·        Note: Uplink synchronization aspect will not be discussed under this A.I.

·       FFS: Whether the above procedures prior to the reception of L1/L2 cell switch command can be performed on candidate cell when it is deactivated SCell (if defined in RAN2)

Detailed discussion will be commenced after receiving RAN2 LS.

 

9.12.22     Timing advance management to reduce latency

R1-2208383        Latency Reduction and Target TA Determination for L1/L2 Mobility               FUTUREWEI

·        Proposal 1: Before cell switch command is received, if the RSRP of a candidate cell is above a threshold, the UE starts acquiring, tracking and storing the candidate’s DL timing information including RSTD and MIB.

·        Proposal 2: Upon receiving the cell switching command, the UE applies the stored most recent RSTD and MIB to achieve the DL synchronization of the target cell.

·        Proposal 3: Support RACH-less access to the target during the mobility.

·        Proposal 4: Upon reception of target access command, UE indication of the SSB/CSI-RS selected as the target beam is supported for mobility RACH-less access. Indication methods and details are FFS.

·        Observation 6: For intra-DU TRP switching, the TA of the target TRP for after switching can be obtained by UE adjusting the TA obtained before switch without using RACH.

·        Proposal 5: For intra-DU TRP switch, before the UL transmission to the target TRP started, the UE determines TA of the target TRP by adjusting the TA-update from the network with RSTD.

·        Proposal 6: For inter-DU L1/L2 mobility, support the network assisted target_TA determination performed at the UE by adjusting the Source_TA with RSTD and a network TA adjustment factor.

Decision: The document is noted.

 

R1-2208407         Timing advance management to reduce latency          Huawei, HiSilicon

R1-2208501         Discussion on timing advance management for L1/L2-based inter-cell mobility               Nokia, Nokia Shanghai Bell

R1-2208510         Enhancements on TA management to reduce latency ZTE

R1-2208571         Discussion on timing advance management to reduce latency  Spreadtrum Communications

R1-2208665         Discussion on TA management for L1/L2 moblity     vivo

R1-2208748         Timing advancement management for L1L2 mobility Lenovo

R1-2208806         Discussions on Timing Advance Management            OPPO

R1-2208885         On TA management for NR mobility enhancement    Google

R1-2208959         On timing advance management to reduce latency      CATT

R1-2209074         On Timing Advance Management  Intel Corporation

R1-2209204         Timing advance management to reduce latency          InterDigital, Inc.

R1-2209269         Discussion on Timing advance management xiaomi

R1-2209360         Discussion on timing advance management to reduce latency  CMCC

R1-2209499         UL Timing management to reduce handover latency  MediaTek Inc.

R1-2209542         Timing advance management to reduce latency          Ericsson

R1-2209604         Timing advance management to reduce mobility latency          Apple

R1-2209755         Non-serving cell TA management for NR mobility enhancement           Samsung

R1-2209924         Timing advance enhancement for inter-cell mobility  NTT DOCOMO, INC.

R1-2210009         TA management to reduce latency for L1/L2 based mobility    Qualcomm Incorporated

R1-2210200         Timing advance alignment with low latency Rakuten Symphony

 

[110bis-e-R18-Mobility-02] – Xin (CATT)

Email discussion on TA management by October 19

-        Check points: October 14, October 19

R1-2210390        Moderator summary on timing advance management: Round 1       Moderator (CATT)

From Oct 17th GTW session

Agreement

Support TA acquisition of candidate cell(s) before cell switch command is received in L1/L2 based mobility.

·        FFS: whether this can be applied to candidate cell when it is deactivated SCell (if defined in RAN2).

 

From Oct 19th GTW session

Agreement

On mechanism to acquire TA of the candidate cells, the following solutions can be further studied:

·        RACH-based solutions

o   e.g., PDCCH ordered RACH, UE-triggered RACH, higher layer triggered RACH from NW other than L3 HO cmd

·        RACH-less solutions

o   e.g., SRS based TA acquisition, Rx timing difference based, RACH-less mechanism as in LTE, UE based TA measurement (including UE based TA measurement with one TAC from serving cell)

Agreement

For TA acquisition of a candidate cell before cell switch command is received, study at least the following alternatives of associating TA/TAG to candidate cell:

·        Alt1: Associate TA/TAG and candidate cell implicitly, e.g.,

o   the association between TA/TAG and TCI states can be configured

·        Alt2: Associate TA/TAG and candidate cell explicitly, e.g.,

o   the association is provided as a part of candidate cell(s) configuration

o   the association between TA/TAG and SSB(s)/TRS(s) is provided as a part of candidate cell(s) configuration


 RAN1#111

9.12   Further NR mobility enhancements

Please refer to RP-222332 for detailed scope of the WI on further NR mobility enhancements.

 

R1-2212850        Session notes for 9.12 (Further NR mobility enhancements)              Ad-Hoc Chair (CMCC)

Endorsed and contents incorporated below.

 

[111-R18-Mobility] – Parisa (MediaTek)

To be used for sharing updates on online/offline schedule, details on what is to be discussed in online/offline sessions, tdoc number of the moderator summary for online session, etc

9.12.1     L1 enhancements for inter-cell beam management

Including L1 measurement and reporting, beam indication, dynamic switch mechanism among candidate serving cells (including SpCell and SCell), and discussions on RAN2 triggered issues in R1-2210810. For the RAN2 triggered issues, please capture the discussions in a separate section for better work management during the meeting.

 

R1-2210897         L1 enhancements for inter-cell beam management      Huawei, HiSilicon

R1-2210942         L1 enhancements for inter-cell beam management      ZTE

R1-2211028         Discussion on L1 enhancements for L1/L2 mobility   vivo

R1-2211053         L1 enhancements to inter-cell beam management       Ericsson

R1-2211083         Views on L1 enhancements for inter-cell beam management    Fujitsu

R1-2211130         On Intercell beam management enhancement for NR mobility enhancement               Google

R1-2211180         Discussion on L1 enhancements for inter-cell beam management           CATT

R1-2211250         Discussion on L1 enhancements for inter-cell beam management           Spreadtrum Communications

R1-2211297         L1 enhancements for inter-cell beam management      Lenovo

R1-2211306         Discussion on L1 enhancements for L1/L2-triggered mobility Nokia, Nokia Shanghai Bell

R1-2211322         L1 enhancements for inter-cell beam management      InterDigital, Inc.

R1-2211346         Discussion on L1 enhancements for inter-cell beam management           xiaomi

R1-2211418         L1 Enhancements for Inter-cell Beam Management   Intel Corporation

R1-2211440         Discussions on Inter-cell beam management enhancement       OPPO

R1-2211702         Discussion on L1 enhancements for inter-cell beam management           CMCC

R1-2211753         Discussion on L1 enhancements for inter-cell beam management           NEC

R1-2211832         L1 enhancements to inter-cell beam management       Apple

R1-2211873         Enhancements on inter-cell beam management for mobility     LG Electronics

R1-2212004         Discussion on L1 enhancements for inter-cell mobility             NTT DOCOMO, INC.

R1-2212068         On L1 enhancements for inter-cell beam management Samsung

R1-2212140         L1 Enhancements for Inter-Cell Beam Management   Qualcomm Incorporated

R1-2212235         L1 enhancements for inter-cell beam management      MediaTek Inc.

 

R1-2212741        FL summary 1 on L1 enhancements for inter-cell beam management               Moderator (Fujitsu)

From Nov 15th session

Agreement

·        For Rel-18 LTM, L1 inter-frequency measurement is supported from RAN1 point of view.

Agreement

·        Regarding the potential RAN1 enhancements to reduce the handover delay / interruption for Rel-18 LTM

o   Support at least DL synchronization for candidate cell(s) based on at least SSB before cell switch command

§  Further study the necessary mechanism, e.g. signaling and UE capability

Agreement 

For L1 measurement report for Rel-18 L1/L2 mobility, if UE event triggered report for L1 measurement is supported based on further study

·        At least the following aspects may be considered

o   How to define UE event and exact definition of events,

o   Report container

o   Resource allocation/assignment for UE event triggered report

o   Necessity of indication to gNB when the condition UE event is met, and how

o   Necessity to define the condition to start/stop the reporting,

o   Contents of the report/reporting format, PCI, RS ID, measurement result etc.

o   The interaction with filtered L1 measurement results (if supported)

o   Support of simultaneous configuration of both UE event triggered and any of periodic/semi-persistence/aperiodic reporting, and solutions when both of them are configured.

o   Report destination, whether the report is sent to serving cell only or can be sent to one or more candidate cell(s).

o   Benefit when L3 measurement is involved

 

R1-2212858        FL summary 2 on L1 enhancements for inter-cell beam management               Moderator (Fujitsu)

From Nov 17th session

Agreement

Send an LS to RAN2, 3 and 4 to inform them of the agreements under A.I 9.12.1 and A.I. 9.12.2 at RAN1#111.

 

Agreement

For candidate cell measurement for Rel-18 LTM,

·        SSB based L1-RSRP is supported for intra-frequency measurement

·        SSB based L1-RSRP is supported for inter-frequency measurement from RAN1 point of view

·        FFS: L1-SINR, CSI-RS based L1-RSRP

 

Agreement

The beam indication of candidate cell(s) for Rel-18 LTM should be designed based on the following:

·        Beam indication for Rel-18 LTM is designed based on Rel-17 unified TCI framework, if both serving cell and candidate cell support Rel-17 unified TCI framework

·        FFS: whether/how to design mechanism for Beam indication for Rel-18 LTM when at least one from serving cell and candidate cell supports only Rel-15 TCI framework.

·        Note: How and whether to indicate the new serving cell(s) and timing for beam indication are separately discussed

Agreement

For gNB scheduled L1 measurement report for Rel-18 LTM, report as UCI is supported

 

Agreement

 

R1-2212947        DRAFT LS on RAN1 agreements for L1/L2-based inter-cell mobility               Fujitsu, CATT

Decision: As per decision on Nov 18th, the draft LS is endorsed. Final LS is approved in R1-2212948.

 

 

Final FL summary in R1-2212946.

9.12.22     Timing advance management to reduce latency

R1-2210853         Comparison of TA acquisition schemes for L1/L2 Mobility     FUTUREWEI

R1-2210898         Timing advance management to reduce latency          Huawei, HiSilicon

R1-2210943         Enhancements on TA management to reduce latency ZTE

R1-2211029         Discussion on TA management for L1/L2 Mobility    vivo

R1-2211131         On TA management for NR mobility enhancement    Google

R1-2211181         Discussion on timing advance management to reduce latency  CATT

R1-2211251         Discussion on timing advance management to reduce latency  Spreadtrum Communications

R1-2211298         Timing advancement management for L1L2 mobility Lenovo

R1-2211307         Discussion on timing advance management for L1/L2-triggered mobility               Nokia, Nokia Shanghai Bell

R1-2211323         Timing advance management to reduce latency          InterDigital, Inc.

R1-2211347         Discussion on Timing advance management xiaomi

R1-2211419         On Timing Advance Management  Intel Corporation

R1-2211441         Discussions on Timing Advance Management            OPPO

R1-2211553         Timing advance management for L1/L2 Mobility       Ericsson

R1-2211703         Discussion on timing advance management to reduce latency  CMCC

R1-2211833         Timing advance management to reduce latency          Apple

R1-2212005         Timing advance enhancement for inter-cell mobility  NTT DOCOMO, INC.

R1-2212069         Candidate cell TA acquisition for NR L1/L2 mobility enhancement       Samsung

R1-2212141         TA management to reduce latency for L1/L2 based mobility    Qualcomm Incorporated

R1-2212239         UL Timing management to reduce handover latency  MediaTek Inc.

R1-2212321         Reduced latency for inter-cell beam management       Rakuten Symphony

 

R1-2212689        Moderator summary on Timing advance management: Round 1      Moderator (CATT)

From Nov 15th session

Agreement

On mechanism to acquire TA of the candidate cell(s) in Rel-18 LTM, at least support PDCCH ordered RACH.

·           The PDCCH order is only triggered by source cell

·           FFS: the details including content of DCI, RACH resource configuration, RAR transmission mechanism, etc.

·           Note: any other RACH-based solutions are for discussion separately

Agreement (made in RAN1#110b-e)

Support TA acquisition of candidate cell(s) before cell switch command is received in L1/L2 based mobility.

·        FFS: whether this can be applied to candidate cell when it is deactivated SCell (if defined in RAN2)

 

R1-2212815        Moderator summary on Timing advance management: Round 2      Moderator (CATT)

From Nov 16th session

Agreement

For PDCCH ordered RACH in LTM, at least the following enhancements are supported

·        Introduce indication of candidate cell and/or RO of candidate cell in DCI

·        configuration of RACH resource for candidate cell(s) is provided prior to the PDCCH order

·        FFS: whether/how to transmit RAR

 

R1-2212863        Moderator summary on Timing advance management: Round 3      Moderator (CATT)

From Nov 17th session

Agreement

On whether RAR is needed for PDCCH ordered RACH for a candidate cell in LTM, the following alternatives are considered for further study

 

Agreement


 RAN1#112

9.12   Further NR mobility enhancements

Please refer to RP-223520 for detailed scope of the WI on further NR mobility enhancements.

 

R1-2302068        Session notes for 9.12 (Further NR mobility enhancements)              Ad-Hoc Chair (CMCC)

 

[112-R18-Mobility] – Yosuke (Fujitsu)

To be used for sharing updates on online/offline schedule, details on what is to be discussed in online/offline sessions, tdoc number of the moderator summary for online session, etc

9.12.1     L1 enhancements for inter-cell beam management

Including L1 measurement and reporting, beam indication, dynamic switch mechanism among candidate serving cells (including SpCell and SCell), and discussions on RAN2 triggered issues in R1-2210810. For the RAN2 triggered issues, please capture the discussions in a separate section for better work management during the meeting.

 

R1-2300056         L1 enhancements for inter-cell beam management      FUTUREWEI

R1-2300128         L1 enhancements for inter-cell beam management      Huawei, HiSilicon

R1-2300145         FL plan on L1 enhancements for LTM at RAN1#112 Moderator (Fujitsu)

R1-2300188         L1 enhancements for inter-cell beam management      ZTE

R1-2300239         Discussion on L1 enhancements for inter-cell beam management           Spreadtrum Communications

R1-2300311         Discussions on Inter-cell beam management enhancement       OPPO

R1-2300335         L1 enhancements to inter-cell beam management       Ericsson

R1-2300384         Layer-1 Enhancements for L1/L2-triggered Mobility Nokia, Nokia Shanghai Bell

R1-2300474         Discussion on L1 enhancements for L1L2 mobility    vivo

R1-2300488         Discussion on L1 enhancements for inter-cell beam management           FGI

R1-2300517         L1 enhancements for inter-cell beam management      Lenovo

R1-2300536         Enhancements on inter-cell beam management for mobility     LG Electronics

R1-2300557         Discussion on L1 enhancements for inter-cell beam management in LTM               Xiaomi

R1-2300662         Further discussions on L1 enhancements for inter-cell beam management               CATT

R1-2300757         Views on L1 enhancements for inter-cell beam management    Fujitsu

R1-2300769         Discussion on L1 enhancements for inter-cell beam management           NEC

R1-2300891         Discussion on L1 enhancements for inter-cell beam management           Sony

R1-2300967         L1 Enhancements for Inter-cell Beam Management   Intel Corporation

R1-2301024         Discussion on L1 enhancements for inter-cell beam management           CMCC

R1-2301161         Discussion on inter-cell beam management  Rakuten Mobile, Inc

R1-2301167         Discussion on L1 enhancements for inter-cell beam management           Google

R1-2301169         L1 enhancements for inter-cell beam management      InterDigital Communications

R1-2301208         Discussion on L1 measurement configuration for LTM             Panasonic

R1-2301287         On L1 enhancements for inter-cell beam management Samsung

R1-2301369         L1 Enhancements to Inter-Cell Beam Management    Apple

R1-2301436         L1 Enhancements for Inter-Cell Beam Management   Qualcomm Incorporated

R1-2301514         Discussion on L1 enhancements for inter-cell mobility             NTT DOCOMO, INC.

R1-2301576         L1 enhancements for inter-cell beam management      MediaTek Inc.

 

R1-2300146        FL summary 1 on L1 enhancements for inter-cell beam management               Moderator (Fujitsu)

From Tuesday session

Agreement

·        RAN1 shares the same understanding as RAN2 on agreement:

o   The LTM mobility trigger information is conveyed in a MAC CE

·        The same MAC CE is used for the LTM triggering.

Agreement

The agreement on scenario 2 (Beam indication together with cell switch command) at RAN1#111 is further clarified as the following:

·        Beam indication for the target cell(s) is conveyed in the MAC CE used for LTM triggering for scenario 2

 

R1-2302001        FL summary 2 on L1 enhancements for inter-cell beam management               Moderator (Fujitsu)

From Wednesday session

Agreement

For L1-RSRP measurement RS configuration

·        For SSB based L1-RSRP measurement:

o   As a starting point, at least the following information needs to be provided to a UE, e.g.

§  For intra- and inter- frequency: PCI or logical ID (e.g., as being defined in R17 ICBM), time domain (e.g. SMTC or periodicity and SSB position in burst)

§  For inter-frequency: frequency domain location (e.g. center frequency), SCS

§  FFS: transmission power (for pathloss calculation)

o   Note: other parameters included in the configuration can be further discussed

o   Including above agreement into the LS

·        The detailed design of RRC structure is up to RAN2, and send an LS to RAN2 to request to work on the RRC structure design on the measurement configuration.

o   Following RAN1 understanding will be provided in the LS

§  RAN1 has discussed the following configuration options for L1 measurement configurations for SSB till RAN1#112:

·        Option 1) Configurations for L1 measurement RS is provided under ServingCellConfig for the serving cells

o   is useful to reuses the mechanism for Rel-17 ICBM and necessary information to support inter-frequency measurement will be added there.

·        Option 2) Configurations for L1 measurement RS is provided separately from ServingCellConfig for the serving cells and CellGroupConfig for the candidate cells

o   is useful to avoid the duplicated configurations for L1 measurement RSs, [and avoid UE to process configurations for L1 measurement RS provided under CellGroupConfig for the candidate cells]

·        Option 3) Configurations for L1 measurement RS is provided under CellGroupConfig for the candidate cells

o   can achieve the similar benefit as Option 2) by directly referring to the candidate cell configurations.

§  Note RAN2 has a full flexibility to design the whole RRC structure design.

§  RAN1 believes this is RAN2 expert region, and respectfully asks RAN2 to finalize the RRC structure design after RAN1 finalizes the discussion on RRC parameters.

§  It is noted that RAN1 foresees the necessity of similar discussions on TCI state pool for candidate cells and L1 measurement report configurations.

 

R1-2302002        FL summary 3 on L1 enhancements for inter-cell beam management               Moderator (Fujitsu)

From Thursday session

Agreement

Send an LS to RAN2,3,4 on the RAN1 agreements in this meeting

·        All agreements in AI 9.12.1 and 9.12.2 in RAN1#112 are included

·        The LS contents agreed in AI 9.12.1 (on L1 measurement configuration) and AI 9.12.2 (on RAR) are also included

 

R1-2302195        FL summary 4 on L1 enhancements for inter-cell beam management               Moderator (Fujitsu)

From Friday session

Agreement

·        At least for Rel-17 unified TCI framework based beam indication included in cell switch command (i.e. scenario 2), beam indication applies to signals/channels that follow or are configured to follow Rel-17 unified TCI at the target cell(s)

·        FFS: beam indication for mTRP case

 

R1-2302193        DRAFT LS on L1 measurement RS configuration and PDCCH ordered RACH for LTM              Moderator (Fujitsu), CATT

Decision: R1-2302193 is endorsed in principle by appending latest agreements. Final LS is approved in R1-2302194.

 

 

Final FL summary in R1-2302196.

9.12.22     Timing advance management to reduce latency

R1-2300057         Discussion of the merits of UE based  RACH-less TA acquisition for LTM               FUTUREWEI

R1-2300129         Timing advance management to reduce latency          Huawei, HiSilicon

R1-2300189         Enhancements on TA management to reduce latency ZTE

R1-2300240         Discussion on timing advance management to reduce latency  Spreadtrum Communications

R1-2300312         Discussions on Timing Advance Management            OPPO

R1-2300385         Timing Advance Management for L1/L2-triggered Mobility    Nokia, Nokia Shanghai Bell

R1-2300475         Discussion on TA management for L1L2 mobility     vivo

R1-2300490         Discussion on TA management for LTM      FGI

R1-2300518         Timing advancement management for L1L2 mobility Lenovo

R1-2300537         Enhancements on TA management for mobility          LG Electronics

R1-2300558         Discussion on Timing advance management Xiaomi

R1-2300663         Discussion on time advance management to reduce latency      CATT

R1-2300968         On Timing Advance Management  Intel Corporation

R1-2301025         Discussion on timing advance management to reduce latency  CMCC

R1-2301035         Discussion on TA management to reduce latency       KDDI Corporation

R1-2301095         Timing advance management for L1/L2 Mobility       Ericsson

R1-2301168         Discussion on timing advance management to reduce latency  Google

R1-2301170         Timing advance management to reduce latency          InterDigital Communications

R1-2301288         Candidate cell TA acquisition for NR L1/L2 mobility enhancement       Samsung

R1-2301370         Timing advance management for L1/L2 Mobility       Apple

R1-2301437         TA management to reduce latency for L1/L2 based mobility    Qualcomm Incorporated

R1-2301515         Timing advance enhancement for inter-cell mobility  NTT DOCOMO, INC.

R1-2301583         UL Timing management to reduce handover latency  MediaTek Inc.

 

R1-2301893        Moderator summary on Timing advance management for LTM: Round 1               Moderator (CATT)

From Tuesday session

Agreement

For Rel-18 LTM, Random Access Preamble indices and indication of RACH occasions with the associated SSB indices are configured for each candidate cell.

Note: the detailed signalling is left to RAN2.

 

Agreement

The PDCCH order from the source cell contains the indication of candidate cell.

·        The reserved bit(s) in DCI format 1_0 for PDCCH order can be used for indication of cell identity

 

R1-2302016        Moderator summary on Timing advance management for LTM: Round 2               Moderator (CATT)

From Wednesday session

Agreement

For PDCCH ordered-RACH for candidate cell(s), RAR reception can be configured/indicated

·        If reception of RAR is not configured/indicated (without RAR)

o   TA value of candidate cell is indicated in cell switch command

o   FFS: whether UE should re-transmit PRACH when reception of RAR is not configured/indicated

o   FFS: how UE determine the transmit power of subsequent PRACH triggered by PDCCH order

·        If reception of RAR is configured/indicated (with RAR), FFS

o   whether RAR is received from serving cell or candidate cell

§  if RAR is received from candidate cell, whether Type1-PDCCH CSS of the candidate cell is configured to the UE

o   content of RAR

·        FFS: signaling for configuration/indication of whether RAR needs to be received

·        UE can report the support combination of with RAR only and without RAR only, where support of one default scheme is the baseline UE approach for LTM

·        Send LS to RAN2 and RAN3 to check the feasibility about this agreement

·        Note: Definition of candidate cells is up to RAN2

 

 

R1-2302075        Moderator summary on Timing advance management for LTM: Round 3               Moderator (CATT)

From Thursday session

Agreement

·        For PDCCH-order based RACH for TA measurement for candidate cells, legacy CBRA is not supported

Agreement

On whether UE should initiate re-transmit PRACH when reception of RAR is not configured/indicated, down select one from the following alternatives.

·        Alt 1: UE autonomous re-transmission of PRACH is not allowed (e.g., by setting the number of allowed PRACH transmission to the minimum value of PreambleTransMax=1)

·        Alt 2: UE autonomous Re-transmission of PRACH is allowed,

o   The number of PRACH transmission will be defined e.g. set the times of RACH transmission to the minimum value of PreambleTransMax

Agreement

If reception of RAR is configured/indicated, RAR contains at least TA of candidate cell.

·        The maximum number of TA values memorized by UE is a UE capability

·        FFS: whether other parameters such as UE ID, candidate cell ID etc. is contained in RAR

Agreement

Whether RAR needs to be received is configured by RRC.

 

 

R1-2302165        Moderator summary on Timing advance management for LTM: Round 4               Moderator (CATT)

From Friday session

Agreement

Study at least the following issues on PDCCH-order based PRACH for candidate cell that is not UL serving cell, i.e. without PUCCH/PUSCH configured

·        Whether gap between the DCI and PRACH longer than timeline defined in spec is needed

·        Any impact/interruption on UL Tx of serving CCs due to the PRACH Tx

Working Assumption

UE-based TA measurement (UE derives TA based on Rx timing difference between current serving cell and candidate cell as well as TA value for the current serving cell) is supported.

·        Corresponding UE capability is to be introduced to support UE-based TA measurement

·        For a UE reports support of this capability, configuration of UE-based TA measurement is supported

·        FFS: other impacts on RAN1 spec


 RAN1#112-bis-e

9.10   Further NR mobility enhancements

Please refer to RP-223520 for detailed scope of the WI on further NR mobility enhancements.

 

R1-2304173        Session notes for 9.10 (Further NR mobility enhancements)              Ad-Hoc Chair (CMCC)

9.10.1     L1 enhancements for inter-cell beam management

Including L1 measurement and reporting, beam indication, dynamic switch mechanism among candidate serving cells (including SpCell and SCell), and discussions on RAN2 triggered issues in R1-2210810. For the RAN2 triggered issues, please capture the discussions in a separate section for better work management during the meeting.

 

R1-2302315         L1 enhancements for inter-cell beam management      FUTUREWEI

R1-2302368         L1 enhancements for inter-cell beam management      Huawei, HiSilicon

R1-2302410         FL plan on L1 enhancements for LTM at RAN1#112bis-e        Moderator (Fujitsu, MediaTek)

R1-2302413         L1 enhancements to inter-cell beam management       Ericsson

R1-2302423         L1 enhancements for inter-cell beam management      ZTE

R1-2302504         Discussion on L1 enhancements for L1/L2 mobility   vivo

R1-2302568         Discussions on Inter-cell beam management enhancement       OPPO

R1-2302619         Discussion on L1 enhancements for inter-cell beam management           Spreadtrum Communications

R1-2302730         L1 enhancements for inter-cell beam management      Lenovo

R1-2302752         Discussion on L1 enhancements for inter-cell beam management           NEC

R1-2302819         L1 Enhancements for Inter-cell Beam Management   Intel Corporation

R1-2302830         Layer-1 Enhancements for L1/L2-triggered Mobility Nokia, Nokia Shanghai Bell

R1-2302860         Discussion on L1 enhancements for inter-cell beam management           Sony

R1-2302867         Discussion on L1 enhancements for L1L2-triggered mobility   Panasonic

R1-2302870         Discussion on L1 enhancements for inter-cell beam management           CATT

R1-2302914         Views on L1 enhancements for inter-cell beam management    Fujitsu

R1-2302966         Discussion on L1 enhancements for inter-cell beam management           Xiaomi

R1-2303082         Enhancements on inter-cell beam management for mobility     LG Electronics

R1-2303148         On L1 enhancements for inter-cell beam management Samsung

R1-2303253         Discussion on L1 enhancements for inter-cell beam management           CMCC

R1-2303288         Discussion on L1 enhancements for inter-cell mobility             KDDI Corporation

R1-2303331         L1 enhancements for inter-cell beam management      MediaTek Inc.

R1-2303410         Discussion on L1 enhancements for inter-cell beam management           FGI

R1-2303455         Discussion on L1 enhancements for inter-cell beam management           InterDigital, Inc.

R1-2303503         L1 enhancements to inter-cell beam management       Apple

R1-2303518         Discussion on L1 enhancements for inter-cell beam management           Google

R1-2303610         L1 Enhancements for Inter-Cell Beam Management   Qualcomm Incorporated

R1-2303727         Discussion on L1 enhancements for inter-cell mobility             NTT DOCOMO, INC.

 

[112bis-e-R18-Mobility-01] – Yosuke (Fujitsu)

Email discussion on L1 enhancements for inter-cell beam management by April 26 - extended till April 28th

-        Check points: April 21, April 26

R1-2303021        FL summary 1 on L1 enhancements for inter-cell beam management               Moderator (Fujitsu, MediaTek)

Presented in April 17th GTW session.

 

R1-2303022        FL summary 2 on L1 enhancements for inter-cell beam management               Moderator (Fujitsu, MediaTek)

From April 19th GTW session

Agreement

·        Adopt Alt.2 for beam indication of target cell(s) and TCI state activation for candidate cell(s) (if supported) ,

o   Alt. 1: By indicating RS identifier, i.e. mapping between RS identifier and Rel-17 unified TCI state is done by a UE

o   Alt. 2: By indicating Rel-17 TCI state index

 

R1-2304090        FL summary 3 on L1 enhancements for inter-cell beam management               Moderator (Fujitsu, MediaTek)

From April 21st GTW session

Agreement

From RAN1 point of view, at least the following information can be included in the cell switch command, which is conveyed by MAC CE

·        FFS: C-RNTI

FFS: the presence of each field (i.e. always present or configurable)

 

 

R1-2304091        FL summary 4 on L1 enhancements for inter-cell beam management               Moderator (Fujitsu, MediaTek)

From April 25th GTW session

Agreement

For the beam selection for SSB based L1-RSRP measurement report,

·        Beam selection is performed across the L cells from configured (or activated, if introduced) cells, i.e. M beams for each of the L cells

o   FFS: How to select the L cells and M beams per cells is up to UE

·        M x L beams are reported in a single report instance

o   Max values of M and L are based on UE capability, and at least M x L=4 is supported as a UE capability, other UE capabilities are FFS

§  FFS if UE is allowed to report less than M x L beams

o   The values of M and L are configured to the UE in the reporting configuration

·        FFS: The following configurability is introduced in the report configuration

o   1) Whether serving cell is always selected in the L cell selection performed by the UE, and applicable when a UE is configured with L>=2

o   2) at least one of the inter-frequency cells is always selected in the L cell selection performed by the UE, and applicable when a UE is configured with L>=2 and at least one cell in inter-frequency

Agreement

For the Rel-17 unified TCI based beam indication in Rel-18 LTM, at least Alt 1 is supported:

FFS: signalling details for TCI state activation

FFS: For Alt 1, whether/how TCI state activation for candidate cell(s) is allowed

Note: If scenarios 1 and 3 are to be supported other beam indication/TCI activation timing relationships are not precluded.

 

 

Decision: As per email decision posted on April 27th,

Agreement

·        Periodic and semi-persistent report on PUCCH are also supported for gNB scheduled L1-measurement reporting.

 

Agreement

·        RRC parameter ss-PBCH-BlockPower for candidate cells is included in the LTM configuration.

o   UE needs the parameter to (at least) perform RACH towards candidate cells

o   Note: how to capture this parameter and RRC structure are up to RAN2

Agreement

Companies are encouraged to study the beam application time for Rel-18 LTM, which may be different from that without serving cell change

·        Definition of the beam application time

·        The exact value(s), condition and UE capability

·        Consider the interaction with the application of the candidate RRC configuration.

Conclusion

Whether active DL and UL BWP of the target Cell/SpCell field, within the cell switch command, is always present or not is left to RAN2 decision.

 

Working Assumption

On the presence of beam indication within cell switch command, at least for scenario 2, following is supported:

·        A field to indicate 1 joint or 1 pair of UL and DL unified TCI State index for the target cell field is always present in the cell switch command.

Note: If scenarios 1 and 3 are agreed to be supported in R18 LTM other solutions may be considered.

 

Agreement

 

 

R1-2304275        DRAFT LS on beam indication of target cell(s) and time gap between a PDCCH order and the corresponding PRACH transmission for LTM            Fujitsu, MediaTek, CATT

Decision: As per email decision posted on April 28th, the draft LS R1-2304275 is endorsed in principle. Final LS is approved in R1-2304276.

 

 

R1-2304274         Final FL summary on L1 enhancements for inter-cell beam management               Moderator (Fujitsu, MediaTek)

9.10.22     Timing advance management to reduce latency

R1-2302316         On TA acquisition schemes of UE based RACH-less and early RACH with RAR               FUTUREWEI

R1-2302369         Timing advance management to reduce latency          Huawei, HiSilicon

R1-2302414         Timing advance management for L1/L2 Mobility       Ericsson

R1-2302424         Enhancements on TA management to reduce latency ZTE

R1-2302505         Discussion on TA management for L1/L2 mobility    vivo

R1-2302569         Discussions on Timing Advance Management            OPPO

R1-2302620         Discussion on timing advance management to reduce latency  Spreadtrum Communications

R1-2302731         Timing advancement management for L1L2 mobility Lenovo

R1-2302814         On Timing Advance Management  Intel Corporation

R1-2302831         Timing Advance Management for L1/L2-triggered Mobility    Nokia, Nokia Shanghai Bell

R1-2302869         Discussion on time advance management to reduce latency      CATT

R1-2302967         Discussion on Timing advance management xiaomi

R1-2303083         Enhancements on TA management for mobility          LG Electronics

R1-2303149         Candidate cell TA acquisition for NR L1/L2 mobility enhancement       Samsung

R1-2303254         Discussion on timing advance management to reduce latency  CMCC

R1-2303260         Discussion on Timing advance management to reduce latency CAICT

R1-2303290         Discussion on Timing advance management to reduce latency KDDI Corporation

R1-2303362         UL Timing management to reduce handover latency  MediaTek Inc.

R1-2303381         Discussion on TA management for L1/L2 mobility    Transsion Holdings

R1-2303456         Discussion on timing advance management to reduce latency  InterDigital, Inc.

R1-2303504         Timing advance management for L1/L2 Mobility       Apple

R1-2303519         Discussion on timing advance management to reduce latency  Google

R1-2303611         TA management to reduce latency for L1/L2 based mobility    Qualcomm Incorporated

R1-2303728         Timing advance enhancement for inter-cell mobility  NTT DOCOMO, INC.

R1-2303782         Discussion on TA management to reduce latency       ITRI

 

[112bis-e-R18-Mobility-02] – Xin (CATT)

Email discussion on TA management by April 26th

-        Check points: April 21, April 26

R1-2303984        Moderator summary on Timing advance management for LTM: Round 1               Moderator (CATT)

From April 17th GTW session

Agreement

For PDCCH ordered-RACH, if reception of RAR is not configured, UE autonomous re-transmission of PRACH is not allowed, regardless of the configuration of PreambleTransMax.

 

Agreement

When reception of RAR is configured, support RAR is received from serving cell at least in intra-DU case.

 

 

R1-2304060        Moderator summary on Timing advance management for LTM: Round 2               Moderator (CATT)

From April 19th GTW session

Agreement

When reception of RAR is configured, support RAR is received from serving cell in inter-DU case.

·        FFS: RA response window related issues

Agreement

For PDCCH ordered RACH mechanism in R18 LTM, when reception of RAR is configured,

·        the UE stores(remembers/maintains/handles) a TA for at least one candidate cell,

·        storing(remembering/maintaining/handling) corresponding TAs for more than one candidate cell is up to UE capability,

o   detailed number of candidate cell is up to UE capability.

 

R1-2304069        Moderator summary on Timing advance management for LTM: Round 3               Moderator (CATT)

From April 21st GTW session

Agreement

For PDCCH-order based PRACH for candidate cell study the following issues:

·        whether/how prioritizations for transmission power reduction for a PRACH transmission to a LTM candidate cell is performed

·        whether/how prioritizations for prioritization of a PARCH transmission to a LTM candidate cell compared to an overlapped (in time and frequency) serving cell UL transmission

 

R1-2304135        Moderator summary on Timing advance management for LTM: Round 4               Moderator (CATT)

From April 25th GTW session

Agreement

For PDCCH ordered-RACH, if reception of RAR is not configured

 

Agreement

Send LS to RAN4 with the following info

 

LS: See the approved LS in R1-2304276 under 9.10.1.