R1-2508696
discussion
Discussion on 6G frame structure
From ZTE
Summary
This ZTE contribution discusses 6G frame structure, numerology, and channel bandwidth, making 10 proposals and 3 observations. Key proposals cover NR-compatible numerology, UE support for 400MHz bandwidth around 7GHz, enhanced frame structure features including native SBFD and subband-based configuration, and larger maximum channel bandwidths across frequency ranges.
Position
ZTE proposes that MRSS between 5G and 6G be considered from day1 with compatible numerology and aligned resource grids including RB, slot, and symbol. They require that only normal CP be supported for communication, opposing shorter or longer CP types. For around 7GHz, ZTE argues UE should support 400MHz bandwidth per carrier via a single FFT operation (Option 1), presenting a technical case against carrier aggregation due to guard band overhead, complicated scheduling/HARQ, and SCell activation delays. They propose dropping dynamic slot format indication from NR while retaining cell-specific TDD configuration, flexible symbol, UE-specific TDD configuration, and concatenated TDD patterns. ZTE requires native SBFD support from day1 with subband-based frame structure configuration and a new mixed DL/UL symbol type for SBFD.
Key proposals
- Proposal 1 (Sec 2.1.2): MRSS between 5G and 6G should be considered in 6GR design, e.g. compatible numerology, and resource aligned in the time domain and frequency including RB, slot, and symbol.
- Proposal 2 (Sec 2.2): The other types of CP (e.g., shorter CP or longer CP than the normal CP) should not be supported.
- Proposal 3 (Sec 2.3): For around 7GHz, UE should support 400MHz bandwidth per carrier.
- Proposal 4 (Sec 2.3): 6GR should support a larger maximum channel bandwidth: 100MHz (for FDD) and 200MHz (for TDD) for sub-6GHz; 800MHz for 24.25GHz - 52.6GHz.
- Proposal 5 (Sec 2.4): The agreement reached in RAN1#122 should be updated to include 15GHz carrier frequency with note that it has not been confirmed by ITU-R/WRC, and to make the frequency range between upper bound of around 7GHz and FR2-1 more general to include both around 10GHz and around 15GHz.
- Proposal 6 (Sec 2.4): The following numerology and maximum channel bandwidth in UE side should be considered in 6G: sub-6GHz FDD 100MHz with 15kHz SCS; sub-6GHz TDD 200MHz with 30kHz SCS; around 7GHz 400MHz with 30kHz SCS; 24.25-52.6GHz 800MHz with 120kHz SCS.
- Proposal 7 (Sec 3.2.1): For the frame structure in 6GR, at least cell-specific TDD configuration, flexible symbol, UE-specific TDD configuration, and concatenated TDD patterns should be supported. Dynamic slot format indication can be dropped.
- Proposal 8 (Sec 3.2.2): Native SBFD should be considered in frame structure design from day1.
- Proposal 9 (Sec 3.2.2): For SBFD in 6GR, one UL subband and one or two DL subbands should be supported.
- Proposal 10 (Sec 3.2.2): RAN1 considers the following enhancement for frame structure in 6GR: subband based frame structure configuration and a new symbol type for SBFD.