R1-2509133
discussion
Discussion on waveform for 6GR air interface
From Ofinno
Summary
This Ofinno contribution (R1-2509133) presents 12 proposals and 17 observations on 6G waveform design, confirming NR CP-OFDM/DFT-s-OFDM as the baseline while advocating for advanced PAPR reduction techniques, UE power boosting, dynamic waveform switching, and consideration of DFT-s-OFDM for downlink. The document systematically addresses uplink enhancements (PAPR reduction, power class, MPR, dynamic switching, multilayer DFT-s-OFDM, MRSS), downlink enhancements (DFT-s-OFDM as additional waveform, MRSS), and suitability of OFDM-based waveforms for high Doppler/delay spread scenarios.
Position
Ofinno proposes confirming both CP-OFDM and DFT-s-OFDM as the baseline uplink waveforms for 6GR and CP-OFDM as the baseline downlink waveform. For uplink coverage enhancement, they propose considering FDSS and FDSS-SE as candidate PAPR reduction techniques for DFT-s-OFDM with at least π/2-BPSK and QPSK modulation, studying reduced MPR values, and requiring PC2 (26 dBm) as a mandatory UE power class for bands above 2 GHz from Day 1. They propose studying DFT-s-OFDM as a potential additional downlink waveform for unicast PDSCH, UE-specific PDCCH, and associated reference signals using at least π/2-BPSK and QPSK to improve coverage and network energy efficiency in both TN and NTN deployments. They propose supporting dynamic waveform switching between DFT-s-OFDM and CP-OFDM from Day 1 and evaluating DFT-s-OFDM for multilayer uplink transmission using MPR as a criterion. They argue that CP-OFDM and DFT-s-OFDM are suitable for most practical 6G deployment scenarios, including high-speed up to 500 km/h, and that sensing-specific waveforms for extreme Doppler/delay spread should be studied separately under agenda item 11.14.
Key proposals
- Proposal 1 (Sec 3): Confirm that CP-OFDM and DFT-s-OFDM waveforms as defined in 5G NR are supported for 6GR for uplink.
- Proposal 2 (Sec 3.1): Consider frequency domain spectrum shaping (FDSS) as a candidate scheme for PAPR reduction for DFT-s-OFDM with at least /2-BPSK and QPSK.
- Proposal 3 (Sec 3.1): Consider FDSS with spectrum extension (FDSS-SE) as a candidate scheme for PAPR reduction for DFT-s-OFDM with at least /2-BPSK and QPSK.
- Proposal 5 (Sec 3.2): Consider high UE power class (e.g., 26 dBm) as a mandatory feature or at least mandatory for higher bands (e.g., above 2 GHz) in 6GR from Day 1.
- Proposal 6 (Sec 3.2): Study the possibility of reducing MPR in 6GR.
- Proposal 7 (Sec 3.3): Support dynamic switching between DFT-s-OFDM and CP-OFDM in 6GR from Day 1.
- Proposal 8 (Sec 3.4): Consider UE power output capability (e.g., MPR) as a criterion for evaluating DFT-s-OFDM for multilayer uplink transmission.
- Proposal 9 (Sec 4): Confirm that CP-OFDM waveform as defined in 5G NR is supported for 6GR for downlink.
- Proposal 10 (Sec 4.1): Consider DFT-s-OFDM as potential additional waveform for downlink.
- Proposal 11 (Sec 4.1): Consider at least /2-BPSK and QPSK as modulation schemes for DFT-s-OFDM waveform in downlink.
- Proposal 12 (Sec 4.1): Target channels/signals for DFT-s-OFDM can be unicast PDSCH, UE specific PDCCH, and relevant reference signals (e.g., DMRS, CSI-RS).
- Proposal 4 (Sec 3.1): Consider both FDSS and FDSS-SE for at least data channel (e.g., PUSCH).