R1-2600051
discussion
6G Synchronization Acquisition and Beam Measurement
From FUTUREWEI
Summary
This 3GPP RAN1 contribution from Futurewei for 6G Radio proposes energy-efficient designs for synchronization, system information, and paging. It presents 5 proposals and 15 observations focusing on longer periodicities for SSB/SIB1, on-demand sync signal/SIB1 mechanisms for standalone cells, clustered paging frame provisioning, and adoption of OFDM-based DL WUS as a baseline UE energy saving mechanism.
Position
Futurewei proposes extending 5G NR network energy saving techniques for 6G by removing backward compatibility constraints, specifically replacing frequent SSB/SIB1 transmissions with infrequent periodic transmissions up to 160ms for any SSB type (CD-SSB and NCD-SSB). They propose a light Sync Signal structure with sequence-based design for indicating UL WUS configuration, beam/Sync Signal index, and LSBs of SFN, arguing this enables on-demand request of MIB/SIB1 in standalone cells and allows the BS to use a low-power transmitter. For paging, they propose clustering/grouping of legacy Paging Frames in time domain via frequency domain multiplexing to align cell DTX/DRX with UE DRX. They require adoption from day one of duty-cycled operations and DL WUS of OFDM-based sequence with at least Rel-17 PEI functionality replacement, citing that DL WUS coverage comparable to a 6GR control channel is achievable when using the standard 6GR UE Noise Figure rather than relying on OOK waveform limitations.
Key proposals
- Proposal 1 (Sec 3): Consider the longer periodicity for Sync Signal (+PBCH) and SIB1 combined with light Sync Signal(s) and on-demand Sync Signal/SIB1 (in any cell type and for UEs in any RRC state) for network energy saving with minimal impact on UE cell search complexity and access latency.
- Proposal 2 (Sec 3): Consider network energy efficiency by adoption of on-demand Sync signal/SIB1 request in standalone cells utilizing sequence-based indication of UL-WUS configuration, beam/Sync Signal index, and/or LSBs of SFN, and UL WUS design based on limited number of sequences and UL WUS listening occasions.
- Proposal 3 (Sec 4): Consider realizing aligned design of cell DTX/DRX and UE duty cycled operations (i.e., IDRX and/or eDRX) using clustered provisioning of cell-common signaling, e.g., with frequency domain multiplexing, for improved network energy saving without sacrificing UEs performance (e.g., paging latency) and power saving.
- Proposal 4 (Sec 4): Consider PFs clustering/grouping combined with grouping information indication by DL-WUS and/or paging messages multiplexing in frequency domain as an approach for aligned Cell DTX/DRX and UE DRX.
- Proposal 5 (Sec 4): Consider the adoption from day one of duty-cycled based operations (iDRX and eDRX) and DL WUS of OFDM based sequence with at least PEI functionality replacement as baseline UE energy saving mechanisms in 6G.