R1-2508864
discussion
6GR energy efficiency
From Ericsson
Summary
Ericsson's 3GPP RAN1 technical document for 6GR Energy Efficiency contains 34 Observations and 30 Proposals, advocating a clean-slate framework that extends NR Rel-15 as the baseline while introducing lean time-domain designs (160 ms SSB periodicity), unified UE power models, and structured DRX/PDCCH monitoring to achieve substantial network and device energy savings.
Position
Ericsson proposes that 6GR adopt NR Rel-15 as the baseline for energy efficiency evaluations, explicitly excluding later NR network and UE energy saving features due to lack of widespread implementation. They require BS Category 1 power models from TR 38.864 as the 6G baseline, oppose introducing Low Power Radio (LPR) into BS power models without common understanding, and argue against specific BS model enhancements for multi-TRP, SBFD, or multi-carrier due to too many unknowns. They propose default SSB periodicity extended to 160 ms for network deep sleep, supported by clustered paging occasions, concentrated SIB broadcast, and differentiated GSCN raster subsets with different UE SSB periodicity assumptions per subset. They oppose using Cell DTX/DRX as a common tool for idle/inactive and connected mode time-domain adaptations, arguing it duplicates UE C-DRX functionality, and recommend RAN2 lead mechanisms for alignment of UL/DL transmissions. For UE energy saving, they propose a structured C-DRX framework with preconfigured PDCCH monitoring sets tied to DRX window types (e.g., OnDuration vs. drx-InactivityTimer) via RRC, eliminating DCI-based switching for each transition, and require OFDM-based WUS to replace Rel-16 DCP and Rel-17 PEI across all RRC states.
Key proposals
- Proposal 1 (Sec Introduction): Study and identify which NR techniques should be baseline in 6GR, studying if/how they can be improved, extended or simplified for larger gains at lower cost.
- Proposal 2 (Sec BS power model): The relative power levels and transition time/energy values agreed for BS Category 1 in TR 38.864 should be used as baseline for 6G evaluations.
- Proposal 6 (Sec Base station low power radio): BS power models are not updated to include LPR unless there is a common understanding of the LPR function.
- Proposal 8 (Sec UE power model): For UE power model, extend bandwidth scaling to cover all bandwidths from less than 10 MHz to larger than 100 MHz with a single power model, and UE active power after multiple scaling should not be lower than micro-sleep power.
- Proposal 11 (Sec Baseline settings): Adopt NR Rel-15 as baseline for 6GR network and UE energy efficiency evaluations.
- Proposal 12 (Sec Network load levels): Update BS load level definitions to Empty (L=0%), Low (0<L≤5%), Light (5<L≤15%), Medium (15<L≤35%).
- Proposal 13 (Sec Sparse transmission): 6GR should support default SSB periodicity of 160 ms to enable network deep sleep states while maintaining acceptable UE Idle mode performance.
- Proposal 17 (Sec Differentiated sync raster): Study a design with multiple GSCN raster subsets where the UE assumption on SSB periodicity for cell search can be different between subsets.
- Proposal 19 (Sec NW discontinuous UL/DL): Cell DTX/DRX should not be used as a common tool for time-domain adaptations of idle/inactive and connected mode transmissions/receptions.
- Proposal 22 (Sec Spatial/power/freq flexibility): SSB-less intra/inter-band SCells operation should be included as baseline functionality in 6GR.
- Proposal 23 (Sec Connected mode DRX): For 6GR, support low-overhead transitions between preconfigured PDCCH monitoring sets without requiring DCI-based signaling for each switch.
- Proposal 27 (Sec Wake up signal): The OFDM-based WUS in 6GR should replace the main functionality of Rel-16 DCP and Rel-17 PEI which provide limited gains.
- Proposal 29 (Sec Wake up signal): The 6GR WUS should be supported in all RRC states (Idle/Inactive, Connected) to provide energy saving benefits for different use cases and scenarios.
- Proposal 30 (Sec Enhanced Cross-slot): Further study Enhanced Cross-Slot Scheduling in 6GR considering impact on scheduling complexity and overlapping functionalities with other UE energy saving schemes (e.g., WUS).