R1-2601862
discussion
Discussion on NTN specific requirements and design for GNSS based operation
From NEC
Summary
This NEC contribution contains 2 Observations and 2 Proposals across sections on NTN LOS MIMO and Mobility/Ephemeris Optimization. It argues for leveraging polarization diversity as a viable MIMO technique in strong LOS satellite channels and proposes studying ephemeris compression to address VLEO constellation overhead.
Position
NEC proposes studying LOS MIMO techniques for NTN that specifically leverage the polarization domain, arguing that LHCP/RHCP orthogonally polarized signals can be separated even in strong LOS environments to create parallel channels independent of multipath scattering. They propose studying ephemeris information compression and prediction techniques for 6G NTN, contending that legacy uncompressed satellite ephemeris broadcast in SIBs is unsustainable for VLEO constellations due to prolonged broadcast times, impractically high update frequencies, and conflict with network energy-saving goals. They present VLEO (100–400 km altitudes) as requiring ultra-rapid handovers (<5 minute visibility) with intense signaling demands and more complex uplink synchronization due to larger Doppler shifts and shorter variable propagation delays.
Key proposals
- Observation 1 (Sec 2): Significant polarization diversity potential exists in satellite communication links, independent of multipath scattering, due to antenna design and propagation effects.
- Proposal 1 (Sec 2): Study LOS MIMO techniques for NTN, specifically focusing on leveraging the polarization domain.
- Proposal 2 (Sec 3): Study ephemeris information compression and prediction techniques to support new applications in 6G NTN.
- Observation 1 (Sec 4): Significant polarization diversity potential exists in satellite communication links, independent of multipath scattering, due to antenna design and propagation effects.
- Proposal 1 (Sec 4): Study LOS MIMO techniques for NTN, specifically focusing on leveraging the polarization domain.
- Proposal 2 (Sec 4): Study ephemeris information compression and prediction techniques to support new applications in 6G NTN.