R1-2600041
discussion
Other aspects of 6GR physical layer operation
From Nokia
Summary
This Nokia contribution discusses tracking reference signal (TRS) design for 6G Radio, presenting 3 Observations and 3 Proposals across sections 2 and 3. The document questions the need for a dedicated 6GR TRS, critiques overhead and channel characteristic mismatch issues with 5G periodic TRS, and proposes prioritizing aperiodic RS designs associated with downlink transmissions.
Position
Nokia questions the necessity of introducing a 6GR-specific TRS before use cases and corresponding requirements are clearly identified. They present a technical case against periodic TRS inherited from 5G, arguing that periodic TRS contributes to system overhead and network energy consumption and experiences different channel characteristics than PDSCH DMRS due to cell-specific wide-beam transmission versus UE-specific precoded transmission. Nokia proposes that 6GR should build upon aperiodic RS design associated with downlink transmissions that shares the same/similar radio channel characteristics as PDSCH DMRS. If TRS usage is retained, they propose studying mechanisms for more flexible TRS adaptation including not transmitting TRS or adapting TRS configuration/setting for overhead reduction and energy savings without compromising performance. Nokia identifies network-side lack of knowledge for timely TRS adaptation, noting such knowledge is available at the UE.
Key proposals
- Proposal 1 (Sec 2): In the study for TRS like signal in 6GR, use cases and corresponding requirements should be clarified.
- Proposal 2 (Sec 2): 6GR should strive on building upon aperiodic RS design associated with downlink transmissions to perform channel parameter estimations and that shares the same/similar radio channel characteristics as PDSCH (DMRS).
- Proposal 3 (Sec 2): If TRS usage(s) is kept in 6GR, study the need to enable more flexible TRS adaptation for the purpose of overhead reduction /energy savings, without compromising performance.
- Proposal 1 (Sec 3): In the study for TRS like signal in 6GR, use cases and corresponding requirements should be clarified.
- Proposal 2 (Sec 3): 6GR should strive on building upon aperiodic RS design associated with downlink transmissions to perform channel parameter estimations and that shares the same/similar radio channel characteristics as PDSCH (DMRS).
- Proposal 3 (Sec 3): If TRS usage(s) is kept in 6GR, study the need to enable more flexible TRS adaptation for the purpose of overhead reduction /energy savings, without compromising performance.