Nokia · 10.5.3.3
Other aspects ·
RAN1#124bis · Source verification
the AI's delta
strengthened
vs RAN1#124
Nokia hardened its TRS position by proposing a concrete candidate — DM-RS based TRS — as a named alternative, where the prior position only questioned 6GR-specific TRS necessity and proposed aperiodic RS generically. The technical case against periodic CSI-RS-based TRS was refined with additional specificity: the channel characteristic mismatch is now named in terms of delay spread and Doppler spread, and energy consumption is now qualified as constant network/UE energy consumption.' A new proposal was added: studying comb-offset hopping to alleviate inter-cell interference when TRS configurations collide across cells. An entirely new topic was added: joint DL/UL CSI acquisition in TDD using the Rel-19 UE antenna model with candidate antenna locations and orientations, with a functional split where SRS-based acquisition serves cell-center UEs and CSI-RS-based acquisition serves cell-edge UEs. The prior proposal for flexible TRS adaptation mechanisms (including not transmitting TRS or adapting configuration) when TRS usage is retained was dropped.
AI-synthesized from contributions · all text is paraphrased
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Contributions at RAN1#124bis · 1 doc
Other aspects of 6GR physical layer operation
Position extracted by AI
Nokia proposes studying DM-RS based TRS as a candidate for time/frequency tracking in 6G, presenting a technical case that periodic CSI-RS-based TRS suffers from high overhead, constant network/UE energy consumption, and mismatch between wide-beam TRS and narrow-beam PDSCH channel characteristics (delay spread, Doppler spread). They require aperiodic RS design associated with downlink transmissions that shares the same radio channel characteristics as PDSCH DMRS. Nokia proposes studying techniques like comb-offset hopping to alleviate inter-cell interference when TRS configurations collide across cells. For CSI acquisition, Nokia proposes studying joint DL and UL based DL CSI acquisition in TDD systems using the new Rel-19 UE antenna model with candidate antenna locations and orientations, noting that SRS-based acquisition serves cell-center UEs while CSI-RS-based acquisition serves cell-edge UEs.
Summary
This 3GPP RAN1 contribution from Nokia presents 6 observations and 6 proposals regarding 6G physical layer operation, focusing on time/frequency tracking reference signal (TRS) design and joint DL/UL CSI acquisition. Nokia argues that 6G should prioritize aperiodic, on-demand DM-RS-based tracking over periodic CSI-RS-based TRS to reduce overhead and energy consumption while better matching PDSCH channel characteristics.
Prior contributions at RAN1#124 · 1 doc · Feb 09, 2026
Other aspects of 6GR physical layer operation
Position extracted by AI
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.
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.
How this was derived
The AI extracted the "position extracted" field above directly from each Tdoc during summarization.
For the delta summary at the top, the AI compared Nokia's consolidated stance at RAN1#124bis
against their stance at RAN1#124 and classified the change as
strengthened.
Always verify critical claims against the original Tdocs linked above.