R1-2509111
discussion
Numerology and frame structure for 6GR air interface
From Apple
Summary
Apple presents 7 proposals on numerology, channel bandwidth, and frame structure for the 6G Radio (6GR) air interface, focusing on simplifying TDD operation and establishing UE capabilities for the ~7GHz range by capping the maximum UE channel bandwidth at 200MHz and relying on carrier aggregation for wider bandwidths.
Position
Apple proposes that maximum UE channel bandwidth for around 7GHz be limited to 200MHz, requiring a 400MHz network channel to support this through 200MHz+200MHz intra-band CA with separate UL/DL capabilities. They require postponing the discussion on subcarrier spacing for around 15GHz until spectrum availability and delay spread analysis are clarified. Apple proposes that the slot remains the scheduling unit and opposes supporting a floating frame structure that crosses the slot boundary for Day-1 6GR. They require using the NR frame structure as a baseline but with the simplification that dynamic TDD is not supported, TDD configurations are limited to a few cell-specifically indicated patterns similar to LTE, and SBFD symbol link direction is RRC-configured.
Key proposals
- Proposal 1 (Sec 2.2): For around 7GHz, support Max CBW 200MHz at UE; a 400MHz CBW NW shall support 200MHz+200MHz CA if UE is capable, with separate capabilities for UL and DL CA.
- Proposal 2 (Sec 2.2): Postpone discussion on SCS for around 15GHz until spectrum availability is clear and further analysis is made on delay spread in that range.
- Proposal 3 (Sec 3): Slot is considered as the scheduling unit.
- Proposal 4 (Sec 3): Do not support a floating frame structure with crossing the slot boundary for Day-1 6GR air interface.
- Proposal 5 (Sec 3): NR frame structure is considered as baseline in 6GR with a simplification: do not support dynamic TDD.
- Proposal 6 (Sec 3): Limit TDD configurations to just a few configurations (similar to LTE), with cell-specific indication as baseline.
- Proposal 7 (Sec 3): If SBFD is considered as a symbol type for 6G day-1, the link direction in SBFD symbols is RRC-configured.