R1-2603261
discussion
FL summary #1 for AI/ML in beam management
From Samsung
Summary
This document summarizes the remaining issues and proposals for AI/ML-based beam management in NR Rel-19, specifically focusing on UE-side model performance monitoring, inference reporting, and processing timelines. It addresses critical specification gaps regarding PUCCH payload sizes for RS-PAI, PDSCH rate-matching around virtual CSI-RS resources, and CPU/APU occupation rules. The document records agreements reached in RAN1#124bis, including the adoption of zero-padding for small RS-PAI payloads and corrections to CPU occupation timelines for data collection.
Position
Samsung supports the majority view on zero-padding RS-PAI payloads to 3 bits for PUCCH transmission, arguing that padding after CSI multiplexing reduces overhead compared to per-report padding. They propose relaxing the configuration restriction for Set A resources to allow different time domain behaviors, enhancing flexibility for AI/ML inference configurations. Samsung requires clarification that CSI-RS resources configured only in Set A are not used for PDSCH rate-matching, thereby preventing unnecessary resource waste. They also support correcting the CPU occupation timeline for UE-side data collection to accurately include periodic CSI reports for beam management. Furthermore, Samsung argues for clarifying the determination of updated AI/ML CSI reports based on CPU and APU availability to ensure higher-priority reports are processed correctly.
Key proposals
- Proposal 2.1.1 (Sec 2.1): Adopt zero-padding for RS-PAI payloads on PUCCH to 3 bits when the configured payload size is 1 or 2 bits, ensuring compatibility with existing PUCCH formats.
- Proposal 2.1 (Sec 2.1): Clarify that for P-CSI and SP-CSI on PUCCH, the parameter nroftransmissionOccasion-r19 shall not be set to values resulting in 1 or 2-bit RS-PAI payloads, preventing unspecified behavior.
- Proposal 1 (Sec 2.1): Define UE behavior for monitoring reports when the linked inference report is stopped, requiring the UE to drop the monitoring report if the inference report is not activated.
- Proposal 2.2.1-A (Sec 2.2): Clarify that CSI-RS resources configured only in Set A (for inference) are not used for PDSCH rate-matching, allowing these resources to be reused for data transmission.
- Proposal 2.2.1-B (Sec 2.2): Specify that NZP CSI-RS resources in Set A are not rate-matched when CSI-ResourcePeriodicityAndOffset is absent, enabling resource utilization during non-transmission occasions.
- Proposal 3 (Sec 2.2): Define that if a CSI-ReportConfig changes from applicable to inapplicable, the UE shall transmit a CSI report containing an invalid value rather than dropping it.
- Proposal 1 (Sec 2.2): Relax the configuration restriction requiring all resources in Set A to have the same time domain behavior, allowing mixed periodicities.
- Proposal 2.3.1 (Sec 2.3): Correct the CPU occupation time definition for UE-side data collection for beam management to accurately reflect periodic CSI report support.
- Proposal 2 (Sec 2.3): Clarify that the maximum value Z and Z' among both M (legacy) and Mx (AI/ML) updated CSI reports are used to determine reference time locations Zref and Z'ref.
- Proposal 3 (Sec 2.3): Clarify CPU/APU determination for updated AI/ML CSI reports, ensuring higher-priority reports are not skipped if lower-priority ones are updated due to PU pool constraints.
- Proposal 4 (Sec 2.3): Specify the CSI computation time for model monitoring CSI reports (RS-PAI) to resolve undefined processing timelines.
- Proposal 2.2 (Sec 2.2): Support virtual resource block mapping of PDSCH where rate matching is performed only if CSI-ResourcePeriodicityAndOffset is configured for NZP CSI-RS in Set A.
- Proposal 1 (Sec 2.2): Endorse text proposals to align RRC parameter notations between TS 38.212/38.214 and TS 38.331.
- Proposal 2.1.1 (Online): Reiterate support for zero-padding RS-PAI to 3 bits for P/SP CSI reporting on PUCCH.
- Proposal 2.2.1-A (Online): Reiterate support for clarifying that CSI-RS only in Set A is not used for PDSCH rate-matching.