R1-2601850
discussion
On sensing evaluations in 6GR
From Nokia
Summary
This Nokia contribution for the 3GPP RAN1 #124bis meeting outlines 23 proposals and 2 observations for structuring the 6G sensing study within the FS_6G_Radio work item. It recommends prioritizing aNB-based monostatic and bistatic sensing modes, reusing Rel-19/20 ISAC channel models and evaluation methodologies as a starting point while proposing specific enhancements to background clutter, micro-Doppler, and target tracking modeling.
Position
Nokia proposes prioritizing aNB-based monostatic and aNB-aNB bistatic sensing modes for the 6G study, arguing UE-based sensing capability is limited due to fewer antenna elements and inability to support simultaneous transmission and reception. They require inter-cell and inter-site interference to be included in system-level sensing evaluations, noting its artificial exclusion in Rel-20 gave optimistic results. Nokia proposes a specific uniformly scattered delay-azimuth clutter backscatter channel model as an alternative to the existing TR 38.901 background model, with parameters like minimum distance to clutter dmin and clutter reflection coefficient rho. For micro-Doppler modeling, they require using a Swerling I model with time-domain filtering parameterized by maximum Doppler shift to enhance target RCS representation. They also propose studying link budget analysis with parameters including 64-element antenna arrays, 100 MHz bandwidth, and specific SNR targets of 17 dB (high) and -3 dB (low) for UAV scenarios.
Key proposals
- Proposal 1 (Sec 2.1): RAN1 will focus the study on the use cases with consensus, i.e., UAV, Human, Vehicle, AGV, and Sensing for communications for 6G sensing.
- Proposal 4 (Sec 2.2): The aNode B based sensing modes are prioritized in the 6G sensing study.
- Proposal 5 (Sec 2.3): RAN1 uses the performance metrics in Rel 20 5GNR ISAC/IMT-2030 as the starting point for 6G sensing.
- Proposal 9 (Sec 2.4): Link-level modeling of 6G ISAC should be discussed in RAN1, to support evaluation and comparison of sensing waveforms, sequences, and granularity for sensing reference signal, and sensing frame structure options.
- Proposal 14 (Sec 2.5.1.2): Consider the proposed uniformly scattered background channel modeling applicable for indoor, outdoor, and dynamic clutter in the 6G sensing study.
- Proposal 15 (Sec 2.5.2): RAN1 revisits the power normalization across the target and background channels in the 6G sensing study.
- Proposal 17 (Sec 2.5.3): Use Swerling model with time-domain filtering parameterized by maximum Doppler shift as the baseline for micro-doppler modeling to enhance RCS model in 38.901.
- Proposal 18 (Sec 2.5.4): Study and agree on mobility models, data association, and tracking filter for target tracking in 6G sensing study.
- Proposal 20 (Sec 2.6): For 6G ISAC, new evaluation assumptions for waveform/sequence for sensing, multiplexing of communication and sensing, antenna tilting, inter-cell/inter-site interference, and tracking should be discussed.
- Proposal 22 (Sec 2.6): Study and agree on the multi-TRP fusion or collaborative sensing techniques and the modeling assumptions.
- Proposal 23 (Sec 2.7): Study to use link budget analysis for 6G sensing performance evaluations. Discuss and agree on the assumptions for the link budget analysis for different use cases and sensing modes.
- Proposal 11 (Sec 2.4): Inter-cell and inter-site interference need to be included in the evaluation assumptions for 6G system level sensing evaluations.
- Proposal 21 (Sec 2.6): No special frame structure assumption for 6G sensing, i.e., a common design for 6G frame structure with and without sensing.
- Proposal 3 (Sec 2.2): How to set up antenna-tilting of aNB antenna should be studied for aNB monostatic and aNB-aNB bistatic sensing, to support both communication and sensing.
- Proposal 8 (Sec 2.3): The sensing modes that cannot meet IMT-2030 requirements should be deprioritized.