R1-2600146
discussion
Bandwidth operation for 6GR
From Huawei
Summary
This document contains 5 observations and 10 proposals from Huawei on bandwidth part (BWP) operation for 6G Radio, covering initial access design, post-access bandwidth expansion, simplified BWP operation, and energy-saving mechanisms.
Position
Huawei proposes supporting BWP operation in 6GR for UEs with different bandwidth capabilities, reduced UE energy consumption, and flexible spectrum usage. For initial access, Huawei proposes studying a single initial DL BWP containing SSB/SIB confined within the UE minimum bandwidth capability and a single initial UL BWP with relaxed center frequency alignment restrictions to avoid PUSCH fragmentation. They propose studying flexible DL/UL pairing mechanisms and efficient initial access for fragment spectrum using anchor/non-anchor CC concepts from NB-IoT, considering system overhead, RACH/paging capacity, and NW/UE energy saving. Huawei identifies lessons from NR BWP including complex parameter configuration, long switching delays due to full RF/BB parameter reloading, and DCI miss detection causing BS-UE active BWP misalignment, and proposes studying simplified BWP operation with reduced BWP-specific RRC parameters, faster switching via BWP groups, and robust switching mechanisms. For energy saving, they propose studying DCI-based BWP switching with modular operation for static power reduction, where BWP switching delay may include time to power on/off separate hardware modules, and joint NW/UE energy saving through integrating energy-saving techniques and ES-friendly configurations into specific BWPs.
Key proposals
- Proposal 1 (Sec 2): Support BWP operation in 6GR to meet the requirements of different scenarios, such as UEs with different BW capabilities, reduced UE energy consumption, flexible spectrum usage, etc.
- Proposal 2 (Sec 3.1): In 6GR, initial DL/UL BWP design should consider all UEs with different BW capability during initial access, e.g. initial DL/UL BWP is confined within the UE minimum bandwidth capability.
- Proposal 3 (Sec 3.1): Study a single initial DL BWP which contains SSB/SIB for UEs with different BW capability during initial access.
- Proposal 4 (Sec 3.1): Study a single initial UL BWP for UEs with different BW capability, and relaxation of the restriction on the alignment of the center frequencies of uplink BWP and downlink BWP to achieve flexible spectrum utilization during initial access.
- Proposal 5 (Sec 3.1): Study flexible DL and UL pairing mechanism during initial access.
- Proposal 6 (Sec 3.1): Study efficient initial access mechanism for fragment spectrum by taking into account system overhead (sync/SIB), NW/UE energy saving, and RACH/Paging capacity.
- Proposal 7 (Sec 3.2): After initial access, a larger initial DL/UL BWP can be activated according to UE BW capability: Case 1: If early indication of UE BW capability is not supported, the active time is after UE capability reporting; Case 2: If early indication of UE BW capability is supported, the active time is after RRCSetup/RRCResume/RRCRestablishment.
- Proposal 8 (Sec 3.3): Study at least the following technical directions for 6GR simplified BWP operation: Reduce the number of BWP-specific RRC parameters; Reduce BWP switching delay; Robust BWP switching mechanism to avoid misalignment of real active BWP between BS and UE.
- Proposal 9 (Sec 3.3): Study enhanced BWP mechanism of a virtual cell for non-contiguous spectrum aggregation.
- Proposal 10 (Sec 3.4): Study BWP operation for NW and UE energy saving: DCI-based BWP switching; For reducing UE static power, BWP switching delay may consider the time to turn on/off a separate module; How to achieve efficient joint energy saving for NW and UE, e.g. by integrating energy saving techniques and ES-friendly configurations.