R1-2600153
discussion
Other aspects for MIMO operation
From Huawei
Summary
Huawei discusses enhancements for 6G MIMO operation across four areas: long-term channel information assisted SRS design for sparse patterns and multi-TRP scenarios, TRS for fine synchronization, and PTRS for phase noise compensation. The document contains four proposals and one observation.
Position
Huawei proposes studying long-term channel information to enable sparse SRS design, using deterministic assisted information extracted from environment-dependent deterministic channel information or historical channel samples to reconstruct dense CSI from sparse SRS measurements. They propose combining instantaneous SRS with long-term channel information for multi-TRP coordination, leveraging the signal space obtained by CSI-RS to filter noise and interference for remote coordinating TRPs. They require studying 6GR TRS using NR TRS as a starting point while minimizing overhead. They propose studying 6GR PTRS for high modulation order cases around 7GHz, emphasizing low-density PTRS patterns in time and frequency domains for phase noise estimation and channel time variation tracking.
Key proposals
- Proposal 1 (Sec 2.1): 6GR should study and consider leveraging long-term channel information to facilitate sparse SRS design and high-precision uplink-based CSI acquisition.
- Proposal 2 (Sec 2.2): 6GR MIMO should study the utilization of long-term channel information to facilitate SRS based CSI acquisition, especially for multi-TRP cooperation scenarios.
- Proposal 3 (Sec 3): 6GR TRS for finer time/frequency synchronization shall be studied, considering NR TRS as a starting point and minimizing 6G TRS overhead as much as possible.
- Proposal 4 (Sec 4): 6GR PTRS shall be studied for cases, e.g. high modulation order around 7GHz considering low density of PTRS pattern at time/frequency domains.
- Observation (Sec 2.2): For channel acquisition of large-scale multi-TRP coordination, combination of instantaneous SRS and long-term channel information can take the advantages of both SRS and CSI-RS, which is UE-friendly and with high accuracy.