R1-2508563
discussion
Feature Lead summary #2 on 6G waveform
From Nokia
Summary
This is the moderator's Feature Lead summary #2 on 6G waveform from RAN1#123 (Nokia), compiling 44 Tdocs containing 287 observations and 285 proposals across 41 pages. The document covers DL/UL PAPR reduction, other waveforms, and Rank > 1 for UL DFT-s-OFDM, with offline/online discussion questions and company comments.
Position
Nokia serves as moderator/Feature Lead, compiling consensus questions and proposals rather than advocating a single position. However, their own contributions reveal specific stances: (1) They propose deprioritizing DL DFT-s-OFDM study, arguing PAPR is comparable to CP-OFDM with transparent techniques and no meaningful NES/coverage gain exists. (2) They propose deprioritizing Zak-OTFS, stating CP-OFDM outperforms it with realistic channel estimation. (3) They support FDSS and FDSS-SE with transparent filtering for 6G UL. (4) They require CP-OFDM for all number of layers in UL and question the potential of UL DFT-s-OFDM for >1 layer, proposing specific net gain evaluation for power-limited vs non-limited UEs. (5) They propose high power class and power boosting features as 6G baseline, with dynamic waveform switching via DCI in the first release. (6) They define evaluation methodology using net gains assuming similar spectral efficiency and bandwidth for compared methods.
Key proposals
- Proposal 3 (Sec 8.4): RAN1 to study adopting Downlink DFT-s-OFDM for low data rate MBB in TN as part of NES and coverage (from Lenovo).
- Proposal 18 (Sec 8.4): RAN1 to consider the following system level configuration for multi-layer UL waveforms study.
- Proposal 1 (from Nokia, Sec 7): CP-OFDM as defined in 5G NR is supported for 6G DL; DFT-s-OFDM or any other OFDM-based waveform will be studied as potential additional waveform.
- Proposal 3 (from Nokia, Sec 3): RAN1 to deprioritize DFT-s-OFDM study for DL (PAPR comparable to CP-OFDM with transparent techniques, no meaningful NES/coverage gain).
- Proposal 6 (from LG, Sec 3): DFT-s-OFDM supported as additional basis for 6GR in DL, at least for single UE-dedicated PDSCH.
- Proposal 7 (from LG, Sec 3): For DL low-PAPR proposals, primary evaluation criterion is Net Gain = Tx power gain - link loss @ Target KPI.
- Proposal 18 (from Nokia, Sec 6): RAN1 to consider system level configuration for multi-layer UL waveforms study (UMA, 21 cells, 10-50 UEs/cell, full buffer).
- Proposal 19 (from Nokia, Sec 6): RAN1 to consider link level configuration for multi-layer UL waveforms study (3.5/7 GHz, 2 or 4 UE ports, CDL-A30).
- Proposal 7 (from Nokia, Sec 5): FDSS and FDSS-SE are supported in 6G Radio.
- Proposal 8 (from Nokia, Sec 5): Transparent filtering approach is assumed for FDSS and FDSS-SE.
- Proposal 1 (from Huawei, Sec 4): Take Tables 1-4 as start point for low PAPR waveform enhancement evaluations.
- Proposal 4 (from Nokia, Sec 5): RAN1 to deprioritize studying Zak-OTFS (CP-OFDM outperforms with realistic assumptions).
- Proposal 6 (from NEC, Sec 3): Support of low PAPR waveforms like DFT-s-OFDM for 6G DL transmissions.
- Proposal 1 (from Ericsson, Sec 3): RAN1 to deprioritize study of DFT-s-OFDM for DL due to lack of significant advantage versus CP-OFDM.
- Proposal 9 (from vivo, Sec 3): Transparent solutions are the baseline of DL low-PAPR waveform for coverage/NES motivation.