R1-2600120
discussion
Discussion on aspects of uplink-based CSI acquisition for 6GR
From Spreadtrum
Summary
This document from Spreadtrum presents 10 proposals and 4 observations regarding 6G SRS design, covering antenna port support, AI-based overhead reduction, and unified sensing/communication RS design for 6GR Day1 study.
Position
Spreadtrum proposes limiting 6GR Day1 SRS study to {1,2,3,4} antenna ports, noting 8-port devices lack commercial deployment despite NR support. They recommend reusing Zadoff-Chu sequences as the SRS baseline and studying cross-slot SRS features beyond 14 symbols for both CSI acquisition and velocity estimation in sensing. For AI-based SRS, they argue antenna switching enhancement should remain NW implementation without spec impact (Observation-2), while prioritizing frequency hopping overhead reduction with Sub-case A where the NW-side model predicts full-bandwidth channel information from sparse SRS transmissions. They prefer a unified uplink RS design aggregating communication, positioning, and sensing functions, and propose studying simplified single-step offset indication for aperiodic SRS timing determination.
Key proposals
- Proposal-1 (Sec 2): {1,2,3,4} antenna-port SRS can be studied in 6GR day1.
- Proposal-3 (Sec 2): Support periodic/SP/aperiodic SRS for 6GR.
- Proposal-4 (Sec 2): Use Zadoff-Chu sequence as a start point for SRS in 6GR.
- Proposal-5 (Sec 2): Study the cross-slot feature for SRS in 6GR day1.
- Proposal-6 (Sec 2): Study simplified offset indication methods for aperiodic SRS.
- Proposal-7 (Sec 2): Solutions to improve SRS coverage can be studied in 6GR, e.g., partial sounding.
- Proposal-8 (Sec 2): Solutions to minimize SRS interference can be studied in 6GR, e.g., comb offset randomization, cyclic shift randomization, etc.
- Proposal-9 (Sec 2): Unified uplink RS design for communication and sensing is preferred.
- Proposal-10 (Sec 3.2): Prioritizing SRS overhead reduction with Sub-case A for 6GR AI use case with the following subcase: SRS overhead reduction for frequency hopping