R1-2509337
discussion
Views on 6GR air interface
From CSCN
Summary
CSCN presents 8 numbered proposals across 6 discussion sections (plus introduction/conclusions), advocating for native TN-NTN harmonization in the 6G air interface from day 1. The contribution argues that 5G's treatment of NTN as a separate supplement caused commercial deployment barriers and WG workload duplication, which 6G should avoid by incorporating NTN characteristics into fundamental physical layer designs.
Position
CSCN requires unified TN-NTN physical layer designs from 6G day 1 across frame structure, waveform, channel coding, modulation, initial access, physical layer control, data scheduling, duplexing, and HARQ operation, arguing that 5G's sequential design approach caused commercial NTN deployment barriers and unnecessary WG workload duplication. They propose developing NTN operation without GNSS and/or ephemeris assistance to maximize TN ecosystem leverage and reduce reliance on non-3GPP system information. CSCN proposes that sync signal design and SSB structure should natively incorporate large/varying Doppler and propagation delay characteristics rather than treating these as NTN-specific add-ons, and proposes extending the number of SSB indexes beyond periodicity extension to support advanced MIMO in TN and multi-beam per cell in NTN. They require coverage targets for NTN to be discussed alongside TN taking into account different frequency bands and orbital altitudes, and propose studying initial access reliability schemes including adaptable RACH occasion (RO), paging occasion (PO), and Type0 PDCCH CSS monitoring occasion (MO) designs. CSCN requires interference mitigation to be a fundamental design requirement covering TN-NTN coexistence, inter-orbit, and inter-satellite cases, and additionally discusses on-board energy efficiency techniques and lightweight AI/ML deployment for regenerative satellite payloads.
Key proposals
- Proposal 1 (Introduction): Unified TN-NTN designs should be supported in 6G day1 for key aspects including frame structure, waveform, channel coding, modulation, initial access, physical layer control, data scheduling, duplexing, and HARQ operation.
- Proposal 2 (Introduction): NTN without GNSS and/or ephemeris assistance should be developed in 6G day 1.
- Proposal 3 (Sec 2.1): Diverse device types should inherently be capable of operating in TN as well as NTN systems with configurable parameters.
- Proposal 4 (Sec 2.2): The design of sync signals and SSB structure should be included in the aspects for supporting NTN to inherently incorporate NTN characteristics.
- Proposal 5 (Sec 2.2): Paging enhancement should be added to the considerations for supporting NTN.
- Proposal 6 (Sec 2.3): Coverage targets for NTN should also be discussed along with TN.
- Proposal 7 (Sec 2.3): Potential schemes should be studied for achieving satisfactory coverage performance and enhancing reliability, especially during the initial access stage; beam hopping, sync signal periodicity extension, and adaptable designs should be supported in 6GR; same mechanisms for improving link-level coverage performance should be considered for TN and NTN, while allowing configurable parameters to accommodate NTN characteristics.
- Proposal 8 (Sec 2.4): Interference mitigation capabilities shall be incorporated as fundamental design requirements for integrated air interface, involving TN-NTN, inter-orbit, and inter-satellite cases.