R1-2601846
discussion
On WUS operation in different RRC states
From Nokia
Nokia's prior position on
10.6.1.2
at
RAN1#124
· AI-synthesized, paraphrased
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Proposes assuming duty-cycled 6GR WUS monitoring with predefined time occasions rather than continuous monitoring, arguing this is necessary to attain UE power benefit given the agreed power model. Proposes that WUS monitoring occasions be limited to one time occasion per paging cycle containing one or more continuous WUS monitoring occasions, as increasing monitoring occasions may negatively impact UE power savings. For connected mode, proposes retaining a basic duty-cycled C-DRX configuration and aligning 6GR WUS monitoring with the C-DRX configuration (Option 1-1), citing reduced RRM measurement cost in the 6G EE processing state. Proposes studying WUS usage within ACTIVE times (previously deprioritized in NR Rel-19) and extending WUS to support multiple PDCCH monitoring adaptation features including SSSG switching, early termination of PDCCH skipping, and SPS activation/deactivation, while striving to avoid overlapping functionality that occurred in 5G across Cell-DTX, DCP, and LP-WUS.
Summary
This 3GPP RAN1 document from Nokia presents 16 proposals and 10 observations concerning 6G DL WUS operation across RRC Idle/Inactive and Connected modes, with extensions to IoT. The contribution covers WUS monitoring configuration, EE processing state impacts on measurements, and PDCCH monitoring adaptation features, aiming to establish study assumptions for the 6GR physical layer design.
Position
Nokia proposes that 6GR DL WUS monitoring be duty-cycled with predefined time occasions and that PDCCH/PDSCH-based paging be supported as the triggered response. They argue that using EE processing state for serving and neighbor cell RRM measurements is feasible and significantly increases power saving gains, but they identify large residual CFO as a risk to measurement accuracy and propose assuming lower residual synchronization error. For connected mode, Nokia proposes limiting EE processing state applicability to at least SSB-based measurements outside active time, while questioning its use for CSI-RS processing due to computational complexity from multi-port channel matrix estimation and codebook searches. They require a streamlined 6G PDCCH monitoring adaptation feature suite that avoids functional overlaps seen in 5G (e.g., between Cell-DTX/UE-DRX, DCP/WUS, PDCCH skipping/SSSG switching) and propose studying WUS for triggering ACTIVE times with duration indication and SSSG switching. For IoT, they prioritize RRC IDLE/INACTIVE mode DL WUS study.
Key proposals
- Proposal 1 (Sec 2.1.1): For the 6GR study, assume that 6GR WUS monitoring is duty-cycled, with predefined time occasions.
- Proposal 6 (Sec 2.1.2.2): Assume that serving and neighbour cell measurements can be done in EE processing state.
- Proposal 9 (Sec 2.1.3.1): Feasibility and the benefit of 6GR WUS indicating the delivery of system information could be studied.
- Proposal 10 (Sec 2.1.3.2): RAN1 to investigate the benefit of using WUS operation to indicate the applied transmission approach for cell-common signalling.
- Proposal 11 (Sec 2.2.1): When operating in connected mode, the EE processing state is assumed for at least SSB based measurements outside active time.
- Proposal 14 (Sec 2.2.3.1): RAN1 strives for a 6G suite of PDCCH monitoring adaptation features that avoids overlapping functionality.
- Proposal 16 (Sec 2.3): RAN1 prioritizes the study of DL WUS for IoT RRC IDLE/INACTIVE mode use cases.
- Proposal 3 (Sec 2.1.1): For 6GR DL WUS study, assume that PDCCH and PDSCH based paging is supported, and that DL WUS can be used to trigger paging monitoring.
- Proposal 4 (Sec 2.1.1): In 6GR study of DL WUS consider support for larger number of sub-groups. Also consider that UE is able to monitor simultaneously multiple sequences.
- Proposal 7 (Sec 2.1.2.2): Consider assuming lower residual synchronization error for EE processing state.
- Proposal 12 (Sec 2.2.1): When operating in connected mode, RAN1 discuss the possible use of the EE processing state (or variation) for SSB-based measurements inside active time.
- Proposal 15 (Sec 2.2.3.1): RAN1 studies WUS for supporting additional PDCCH monitoring adaptation features, including triggering ACTIVE times with additional indication of ACTIVE time duration and triggering SSSG switching.