R1-2601852
discussion
On waveform for sensing in 6GR
From Nokia
Summary
This Nokia contribution to the 6G sensing study proposes reusing 5G NR baseline OFDM waveforms (CP-OFDM for DL, DFT-s-OFDM and CP-OFDM for UL) for sensing, with studies on enhancements including pulse waveforms like FMCW. It presents preliminary evaluation results showing CP-OFDM outperforms OTFS and DFT-s-OFDM in detection performance while all three perform equally well in range and Doppler estimation, and contains 3 observations and 7 proposals covering waveform selection, frame structure impacts, evaluation assumptions, and KPIs.
Position
Nokia proposes that the RAN1-#122 agreements on baseline waveforms for 6G communications (CP-OFDM for DL, CP-OFDM and DFT-s-OFDM for UL) apply directly to 6G sensing, reusing CP-OFDM as the DL basis waveform and both CP-OFDM and DFT-s-OFDM as UL basis waveforms for sensing. They propose studying enhancements atop these baseline waveforms, including pulse waveforms such as FMCW, framed as dedicated sensing bursts within the CP-OFDM frame structure. They propose studying the impact of CP length, time/frequency granularity of the sensing reference signal, and CPI on sensing performance metrics (PFA, Pmiss, range estimation, Doppler estimation), as well as studying the feasibility of sensing within 6G frame structure and duplexing schemes (TDD, FDD, dynamic TDD, SBFD). They present preliminary simulation results under aNB monostatic mode at 6 GHz with 20 MHz bandwidth and 30 kHz SCS showing CP-OFDM outperforming OTFS and DFT-s-OFDM in Pmiss-vs-SNR detection performance, while all three waveforms perform equally well in RMSE of range estimation and radial velocity estimation. They propose agreeing on evaluation assumptions using Table 2 parameters as the starting point and on KPIs for waveform comparisons.
Key proposals
- Proposal 1 (Sec 2): The RAN1 Agreements in RAN1-#122 apply to 6G sensing waveforms; CP-OFDM is used as basis waveform for DL sensing (aNB as STX); DFT-S-OFDM and CP-OFDM are used as basis waveforms for UL sensing (UE as STX).
- Proposal 2 (Sec 3.2): Possible enhancements to CP-OFDM will be studied in RAN1 for 6GR sensing for aNB transmitting waveform, including pulse waveforms (e.g., FMCW, etc.).
- Proposal 3 (Sec 3.3): Possible enhancements to DFT-S-OFDM and CP-OFDM will be studied in RAN1 for 6GR sensing for UE transmitting waveform, including pulse waveforms (e.g., FMCW, etc.).
- Proposal 4 (Sec 4): Study the impact of CP length, time and frequency granularity of the sensing reference signal, and coherent processing interval (CPI) on sensing performance (PFA, Pmiss, range estimation, Doppler estimation, etc.).
- Proposal 5 (Sec 4): Study the feasibility of sensing within the 6G frame structure and duplexing schemes to identify sensing-friendly options.
- Proposal 6 (Sec 5.3): Agree on the evaluation assumptions for waveform comparisons, taking the assumptions in Table 2 as the starting point.
- Proposal 7 (Sec 5.3): Discuss and agree on the KPIs for the waveform comparisons.