R1-2600160
discussion
Requirements and Design for 6G NTN
From Huawei
Summary
This Huawei document for the 6G NR NTN study item presents 15 proposals and 11 observations addressing system design and evaluation methodology. It covers initial access, beam management, energy saving, HARQ/scheduling, and simulation assumptions for non-terrestrial networks in 6G.
Position
Huawei proposes that 6GR NTN should support boundary-less radio access through satellite switch with resynch without PCI change for regenerative payloads under (quasi) earth fixed cell deployment. They require beam-level PRACH and paging configurations in SIB to enable beam-specific operation, and usage of wide beams for common control channels with narrower beams for dedicated channels. Huawei proposes that beam management procedures should consider UE location, time, and elevation angle rather than relying solely on RSRP measurement and report across candidate beams, due to long latency and small RSRP variations in NTN scenarios. They argue the UV-plane-based projection method is unsuitable for multi-satellite deployment evaluation due to artificial beam distortions and non-uniform beam spacing in ECEF, and propose 3D hexagonal tessellation of Earth as the replacement system-level simulation methodology.
Key proposals
- Proposal 1 (Sec 2.1.1): Increasing SSB periodicity and SSB index in a 6GR-NTN cell at least in S/L band compared with NR-NTN should be considered to achieve 100% coverage ratio for a single satellite and to reduce common control overhead.
- Proposal 2 (Sec 2.1.2): RAN1 should study NTN-specific configurations, including beam-level PRACH and paging configurations, in the SIB to enable beam-specific operation for NTN.
- Proposal 3 (Sec 2.2.1): 6GR NTN should support satellite switch with resynch without PCI change for regenerative payloads considering (quasi) earth fixed cell deployment with LEO constellation.
- Proposal 5 (Sec 2.2.2): To balance the requirement between coverage ratio of a satellite and UE experienced throughput, 6GR-NTN should support usage of wide beams for common control channels and signals and narrower beams for dedicated control and data channels and signals.
- Proposal 6 (Sec 2.2.2): 6GR should support dynamic activation and deactivation of UE transmission and/or reception on a specific Narrow beam, via L1 signaling over Wide/Narrow beam.
- Proposal 8 (Sec 2.2.2): 6GR-NTN should support beam management procedures considering additional UE characteristics e.g. location, time, elevation angle.
- Proposal 9 (Sec 2.3): 6GR NTN should support beam-specific DTX/DRX mechanisms for network and UE energy saving purposes.
- Proposal 7 (Sec 2.2.2): For 6GR NTN design, the beam configuration (e.g. TCI state) should take into account varying UE-satellite zenith/azimuth angles of departure/arrival for earth fixed beam due to fast satellite movement.
- Proposal 10 (Sec 2.4): 6GR-NTN should consider paging of a UE in body loss/NLOS/satellite-misaligned scenarios with additional shielding loss.
- Proposal 11 (Sec 2.5.1): 6GR should consider enhanced HARQ feedback mechanisms to handle large RTT in NTN scenarios.
- Proposal 13 (Sec 3.1.1): The system level simulations for 6G-based NTN should consider a beam layout modelling methodology based on 3D hexagonal tessellation of Earth.
- Proposal 14 (Sec 3.1.2): The system level simulations for 6G-based NTN should consider dense/sparse (V)LEO constellation with massive beam footprints per satellite and uneven UE distribution across the service area.
- Proposal 15 (Sec 3.2): Adopt the evaluation assumptions in the attached spreadsheet.