R1-2601859
discussion
Discussion on bandwidth operation for 6GR
From NEC
Summary
This 3GPP RAN1 contribution from NEC (Tdoc R1-2601859) discusses bandwidth part (BWP) and multi-carrier operation for 6G radio (6GR), presenting 2 observations and 10 proposals. The document addresses the necessity, definition, initial access, and post-initial access operations of BWP, and also covers multi-carrier operation during initial access under a potential Single Cell Multiple Carrier (SCMC) framework.
Position
NEC proposes studying the introduction of BWP concept in 6GR for both DL and UL (Proposal 1), driven by the continued existence of mismatched UE/NW bandwidth capabilities and UE power consumption issues (Observation 1). They propose redefining BWP in 6GR to support non-continuous PRBs across multiple carriers and to decouple DL and UL BWP frequency locations/bandwidths, enabled by the consistent SCS per band and the potential SCMC framework (Proposal 2). NEC proposes relaxing the NR restriction that confines DL bandwidth to CORESET#0 during initial access (Proposal 3) and studies two alternatives for initial BWP operation: a single common pair or multiple pairs with UE selection (Proposal 4), with corresponding options for post-initial access BWP operation (Proposal 5). They propose studying multiple BWP switching schemes including low-power signal and timer-based triggers (Proposal 6), enhancing BWP switching reliability (Proposal 7), and relaxing common message scheduling restrictions tied to CORESET#0 RB numbers (Proposal 8). For multi-carrier operation, NEC proposes studying carrier assignment for common signaling under the SCMC framework (Proposal 9) and the relationship between initial BWPs and carriers (Proposal 10).
Key proposals
- Proposal 1 (Sec 2.1.1): RAN1 can study whether to introduce the concept of BWP in 6GR for DL and UL, respectively.
- Proposal 9 (Sec 2.2): If the Single Cell Multiple Carrier (SCMC) framework is introduced, RAN1 may need to further study which carrier can be used for common signaling during initial access (SSB, SIB1, OSI, paging, Msg1/2/3/4), considering factors like co-location, inter-band, device types, coverage, power efficiency, and load balance.
- Proposal 2 (Sec 2.1.2): RAN1 can study the definition and concept of BWP in 6GR considering aspects like frequency configuration reference with consistent SCS per band, whether PRBs in a BWP can be non-continuous and/or across multiple carriers, and decoupled frequency location/bandwidth for DL and UL BWPs.
- Proposal 4 (Sec 2.1.3): RAN1 can study two alternatives for initial BWP operation: Alt.1 (a single pair of common initial DL/UL BWPs for all UEs) and Alt.2 (multiple pairs of initial DL/UL BWPs configured by NW, with UE selecting one pair).
- Proposal 5 (Sec 2.1.4): RAN1 can study two options for BWP operation after initial access: Option 1 (use common initial BWP pair then configure a dedicated pair for high-throughput UEs) and Option 2 (UE selects initial BWP pair then a dedicated pair is configured/determined by UE for power saving).
- Proposal 6 (Sec 2.1.4): RAN1 can study which BWP switching schemes to adopt in 6GR: RRC (re)configuration, DCI indication, low-power signal, or timer expiry.
- Proposal 3 (Sec 2.1.3): In 6GR, it can be considered to relax the restriction on the operation DL bandwidth confined by CORESET#0 during initial access.
- Proposal 7 (Sec 2.1.4): RAN1 can study some mechanism to enhance the BWP switching reliability in 6GR.
- Proposal 8 (Sec 2.1.4): RAN1 can study some mechanism to relax the common message scheduling which is restricted by the number of RBs of CORESET#0 in NR.
- Proposal 10 (Sec 2.2): RAN1 can further study the relationship between initial DL/UL BWPs and DL/UL carriers for the SCMC framework, e.g., whether initial BWPs can be across multiple carriers.