R1-2409659
LS out
Draft reply LS on applicable functionality reporting for beam management UE-sided model
From vivo
vivo's prior position on
5
at
RAN1#118bis
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Advocates for mandatory associated IDs as essential for AI/ML training-inference consistency and FG-specific granularity in functionality definition, while opposing providing inference configuration in early steps.
Summary
This document is a Liaison Statement from RAN1 to RAN2 regarding the applicable functionality reporting for UE-sided AI/ML models in beam management for Release 19. It provides technical answers to ten specific questions from RAN2 concerning the role of network-side additional conditions, associated IDs, and inference configuration steps, containing no new proposals but clarifying existing RAN1 agreements and working assumptions.
Position
vivo argues that it is not feasible for the UE to determine applicable functionalities without NW-side providing associated IDs first, emphasizing that ensuring consistency of NW-side additional conditions across training and inference is crucial to avoid unpredictable performance degradation. They require that associated IDs in Step 3 be separate from inference configuration, which is reserved for Step 5 within the CSI framework (including report configuration and Set A/Set B). vivo supports the position that inference configuration in Step 3 is unnecessary because it does not activate functionality immediately; instead, activation depends on the time-domain type of the beam report, utilizing existing MAC CE or DCI signaling for semi-persistent or aperiodic reports. They propose that Step 4 reporting should include associated IDs supported by the UE and potentially cell IDs to align understanding of training data sources. Finally, vivo presents a working assumption that associated IDs should be configurable within the CSI framework, while leaving the definition of similar properties for DL Tx beams and alternative signaling methods as FFS.
Key proposals
- Answer to Q3 (Sec 1): Clarifies that while functionality definitions follow legacy FG definitions, the configuration of associated IDs can be FG-specific, and UEs cannot assume NW-side additional conditions are identical across different FGs linked to the same ID.
- Answer to Q4-1 (Sec 1): States it is not feasible for the UE to determine applicable functionalities without NW-side providing associated IDs first, as consistency of NW-side additional conditions across training and inference is crucial to prevent performance degradation.
- Answer to Q4-2 (Sec 1): Argues that while other information (e.g., preferred Set B patterns) may be transmitted in Step 3, it is not inference configuration, and the detailed information is subject to further RAN1 discussion.
- Answer to Q4-3 (Sec 1): Asserts that associated IDs in Step 3 are separate from inference configuration.
- Answer to Q4-4 (Sec 1): Reiterates that detailed information in Step 3, such as interested/preferred Set B patterns, is under RAN1 discussion and is distinct from inference configuration.
- Answer to Q5 (Sec 1): Specifies that Step 4 applicable functionality reporting must at least contain associated IDs supported by the UE, and may include cell IDs linked to those IDs to align UE and gNB understanding.
- Answer to Q6 (Sec 1): Defines Step 5 inference configuration content as CSI framework configuration (report configuration, Set B/Set A) and the associated ID for interference.
- Answer to Q7 (Sec 1): Confirms that providing inference configuration in Step 3 does not activate functionality immediately, making it unnecessary to provide such configuration in Step 3.
- Answer to Q8 (Sec 1): Clarifies that configuration in Step 5 does not immediately activate functionality; activation depends on the time-domain type of the beam report (periodic requires no further signaling, while semi-persistent/aperiodic requires MAC CE or DCI).
- Answer to Q9 (Sec 1): Confirms that multiple applicable functionalities can be activated simultaneously, as current specifications already allow simultaneous processing of multiple beam reports.
- Answer to Q10 (Sec 1): States that extra L1/L2 signaling for functionality activation/deactivation is not needed, as current signaling for beam report activation/deactivation is sufficient.
- Working Assumption (Sec 1): Proposes that for UE-sided models in beam management, support for associated ID is required, with the associated ID at least configurable within the CSI framework.
- FFS Item (Sec 1): Identifies as Further Study (FFS) the details of how to configure/indicate the associated ID via other signals or procedures, and how to define similar properties of a DL Tx beam or beam set/list associated with the same ID.