Top 3 things that happened on 6GR uplink, CSI and DCI at RAN1 #126
The verdict
- RAN1 agreed to study non-coherent, partial-coherent and full-coherent PUSCH precoders for 6GR, with several fixed-codebook options for full coherence. (R1-2606763, chair notes, paragraph 382. R1-2606763, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606763.zip; R1-2606763, chair notes, paragraph 388. R1-2606763, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606763.zip)
- RAN1 agreed to study three DCI-container sizing mechanisms at least for RRC connected state: implicit derivation from RRC, explicit RRC signalling, and sizing independent of UE-specific RRC configuration. Combinations are not precluded. (R1-2606764, chair notes, paragraph 118. R1-2606764, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606764.zip)
- For 6GR uplink, RAN1 supported both dedicated PUCCH and UCI carried on PUSCH. For CP-OFDM PUSCH DMRS, it supported Nmax = 48 for X = 2; the X = 1 value remains FFS, with Nmax no greater than 24. (R1-2606763, chair notes, paragraph 410. R1-2606763, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606763.zip; R1-2606763, chair notes, paragraph 430. R1-2606763, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606763.zip)
What was agreed
UL precoder study. RAN1 agreed to study non-coherent, partial-coherent and full-coherent PUSCH precoders for 6GR. For full-coherent fixed codebooks, the options include NR UL codebook reuse, Grassmannian, per-element phase and amplitude quantization targeting SVD approximation, and DFT-based precoding; other options are not precluded. Existing TS 38.101-1/2 RF coherence requirements are at least the evaluation baseline for coherent UL MIMO.
AgreementFor codebook based PUSCH transmission for 6GR, study the following coherency types of UL precoder Non-coherent type Partial-coherent type Full-coherent type Full-power transmission precoder is [...]R1-2606763, chair notes, paragraph 382. R1-2606763, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606763.zip
AgreementR1-2606763, chair notes, paragraph 388. R1-2606763, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606763.zip
AgreementR1-2606763, chair notes, paragraph 404. R1-2606763, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606763.zip
UCI carriage and PUCCH formats. RAN1 supported both dedicated PUCCH and UCI carried on PUSCH; handling of each UCI type on PUSCH with or without data remains for other agendas. The study covers PUCCH schemes with sequences and no DMRS, and schemes with DMRS and/or channel coding; RAN1 strives for a smaller set, for example up to 2 or 3 formats, differentiated by payload, transmission scheme, waveform, modulation, resource size and multi-user multiplexing, with NR PUCCH formats as the benchmark.
AgreementR1-2606763, chair notes, paragraph 410. R1-2606763, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606763.zip
AgreementR1-2606763, chair notes, paragraph 416. R1-2606763, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606763.zip
PUSCH DMRS parameters. For CP-OFDM PUSCH DMRS, RAN1 supported Nmax = 48 for X = 2 and a comb-based CDM structure including at least comb-2; for X = 1, Nmax remains FFS and is no greater than 24. For single-slot TD-OCC-X DMRS, the agreement applies TD-OCC-X to X consecutive symbols and considers equal spacing between each X DMRS symbols; candidate L values are 1 to 6 for X = 1 and 1 to 3 for X = 2.
AgreementR1-2606763, chair notes, paragraph 430. R1-2606763, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606763.zip
AgreementR1-2606763, chair notes, paragraph 441. R1-2606763, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606763.zip
AI-based DMRS overhead reduction. RAN1 agreed to study an AI-based PUSCH receiver for DMRS overhead reduction, including low-overhead DMRS patterns and at least frequency-domain comb-based patterns. Time-domain patterns remain FFS, and subcase C was deprioritized.
AgreementR1-2606763, chair notes, paragraph 455. R1-2606763, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606763.zip
AgreementR1-2606763, chair notes, paragraph 463. R1-2606763, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606763.zip
DCI-container sizing. RAN1 agreed to study three container-size mechanisms at least for RRC connected state: implicit derivation from RRC configuration, for example using the maximum possible size under applicable configurations; explicit size signalling by RRC; and sizing independent of UE-specific RRC configuration. A combination of alternatives for different use cases is not precluded.
Agreement[...] For Alt 2: the container size(s) are explicitly signalled by the network via RRC For Alt 3’: DCI container size(s) is not dependent on UE-specific [...]R1-2606764, chair notes, paragraph 118. R1-2606764, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606764.zip
Two-stage DCI study. The evaluation starts from single-stage sizes of 40, 60 and 140 bits, excluding CRC. Two-stage cases include Option A with a 20-bit or 40-bit first stage on PDCCH and a second stage the same size as single-stage DCI, and Option B with a 40-bit first stage and a second stage 20 bits smaller than the single-stage DCI; 24-bit CRC is the default and other sizes are not precluded. For the physical-channel study, Option 2 includes modified PDCCH for the second stage or a PDSCH transmission scheme with polar code, QPSK and single-layer transmission as the baseline.
AgreementR1-2606764, chair notes, paragraph 141. R1-2606764, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606764.zip
AgreementR1-2606764, chair notes, paragraph 65. R1-2606764, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606764.zip
AgreementR1-2606764, chair notes, paragraph 70. R1-2606764, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606764.zip
Who pushed what
How should 6GR organize uplink transmission schemes?
NEC proposes studying whether PUSCH and PUCCH schemes can be unified for UL multi-TRP and multi-panel operation, while InterDigital says codebook and non-codebook UL schemes offer complementary benefits. These are different design questions, not opposing positions. Both inputs were submitted to the meeting but marked not treated.
NECNEC proposes studying a unified PUSCH and PUCCH framework for UL multi-TRP and multi-panel operation.Study the feasibility of unifying and simplifying PUSCH/PUCCH transmission schemes, strive for a single, streamlined framework that natively and efficiently supports uplink multi-TRP (decoupled from [...]
R1-2605869, Proposal 2, paragraph 158. R1-2605869, NEC, 3GPP TSG RAN WG1 #126. © NEC. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2605869.zip; register: not treated
InterDigitalInterDigital observes that codebook and non-codebook UL schemes offer complementary benefits.Observation 1: Considering the targets in 6GR including UL coverage enhancement, SBFD operation, and multi-TRP frameworks, both codebook-based and non-codebook-based UL transmission schemes offer complementary [...]
R1-2605372, Observation 1, paragraph 16. R1-2605372, InterDigital, 3GPP TSG RAN WG1 #126. © InterDigital. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2605372.zip; register: not treated
Which acquisition and reporting changes should the 6GR DL-based CSI study evaluate?
The submissions span CSI-RS and reporting overhead, interference information, device and antenna conditions, and possible long-term and short-term CSI handling. These company inputs were marked not treated, so the evidence does not establish a meeting position on the acquisition design.
ETRIETRI identifies trade-offs in angular coverage, link budget and CSI-RS overhead, alongside device and antenna conditions.The following aspects are relevant to DL-based CSI acquisition design: Trade-off among angular coverage, link budget, and overhead of CSI-RS transmission Minimizing the number of [...]
R1-2606244, Observation 1, paragraph 30. R1-2606244, ETRI, 3GPP TSG RAN WG1 #126. © ETRI. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606244.zip; register: not treated
FutureweiFuturewei proposes studying CSI-RS overhead, CSI report overhead and interference-information acquisition.For 6GR DL-based CSI acquisition, support enhancements for CSI-RS overhead reduction, enhancements for CSI report overhead reduction, and enhancements for acquiring interference information.
R1-2605221, Proposal 2-1, paragraph 22. R1-2605221, Futurewei, 3GPP TSG RAN WG1 #126. © Futurewei. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2605221.zip; register: not treated
NTT DOCOMONTT DOCOMO proposes studying how to reduce reporting overhead, for example by separating long-term and short-term CSI measurement or reporting.Study whether/how to optimize DL CSI acquisition framework to minimize the impact from UE reporting overhead, e.g., Separate measurement/reporting for long-term CSI and short-term CSI. [...]
R1-2606507, Proposal 4-5, paragraph 202. R1-2606507, NTT DOCOMO, 3GPP TSG RAN WG1 #126. © NTT DOCOMO. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606507.zip; register: not treated
CATTCATT supports CSI-RS-based reporting and proposes studying use cases and trade-offs for DMRS-based reporting.In the 6GR downlink-based CSI acquisition, support CSI-RS-based CSI reporting. Regarding whether to support DMRS-based CSI reporting, study the following aspects: Potential use cases, e.g. [...]
R1-2605723, Proposal 10, paragraph 133. R1-2605723, CATT, 3GPP TSG RAN WG1 #126. © CATT. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2605723.zip; register: not treated
What functions and categories should the 6GR DCI framework cover?
1Finity and InterDigital propose function lists that include scheduling; InterDigital also includes non-scheduling functions. Quectel proposes a taxonomy of cell-common or broadcast, group-common and UE-specific DCI, without specifying scheduling functions in that proposal. These inputs were marked not treated.
1Finity1Finity proposes prioritizing regular, RACH-related, system-information and paging scheduling, plus other functions.As for functions indicated by DCI, at least the following should be supported with high priority. Regular DL/UL scheduling. RACH related DL/UL scheduling. [...]
R1-2606109, Proposal 3, paragraph 29. R1-2606109, 1Finity, 3GPP TSG RAN WG1 #126. © 1Finity. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606109.zip; register: not treated
InterDigitalInterDigital proposes fallback and non-fallback scheduling, plus non-scheduling functions.Support at least following functions carried by a DCI: Scheduling fallback DL/UL channel, Scheduling non-fallback DL/UL channel, Non-scheduling functions (e.g., CSI trigger, SRS trigger, PDCCH [...]
R1-2606334, Proposal 14, paragraph 99. R1-2606334, InterDigital, 3GPP TSG RAN WG1 #126. © InterDigital. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606334.zip; register: not treated
QuectelQuectel proposes supporting cell-common or broadcast, group-common and UE-specific DCI categories.Consider supporting all three broad categories of DCI: Cell-common/Broadcast DCI, Group-common DCI and UE specific DCI.
R1-2606554, Proposal 1, paragraph 14. R1-2606554, Quectel, 3GPP TSG RAN WG1 #126. © Quectel. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606554.zip; register: not treated
What information and physical arrangement should two-stage DCI use?
Sony proposes a first stage carrying information to decode the second stage, with scheduling and other control information in the second. KT proposes Option B, with part of the scheduling information in the first stage and additional information in the second; Quectel proposes PDSCH for the second stage under its physical-channel Option 2. These submissions were marked not treated.
SonySony proposes a first stage for decoding the second, which carries scheduling or other control information.support the information carried in the two stages so that the 1st stage DCI carries only the information to decode the 2nd stage DCI and [...]
R1-2605980, Proposal 5, paragraph 42. R1-2605980, Sony, 3GPP TSG RAN WG1 #126. © Sony. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2605980.zip; register: not treated
KT Corp.KT proposes Option B, with part of the scheduling information in the first stage and additional information in the second.Proposal 16. The 1st stage DCI carries the information to decode the 2nd stage DCI and part of scheduling info for PDSCH(s)/PUSCH(s) and/or other downlink [...]
R1-2605765, Proposal 16, paragraph 123. R1-2605765, KT Corp., 3GPP TSG RAN WG1 #126. © KT Corp.. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2605765.zip; register: not treated
QuectelQuectel proposes physical-channel Option 2, with PDSCH for the second stage.R1-2606554, Proposal 5, paragraph 32. R1-2606554, Quectel, 3GPP TSG RAN WG1 #126. © Quectel. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606554.zip; register: not treated
Still open
- Container-size details remain FFS, including padding, truncation, bandwidth adaptation, minimum and maximum sizes, the UE monitoring budget Xmax and Ymax, slot versus across-slot limits, multi-carrier cases and the maximum number of sizes for two-stage DCI. (R1-2606764, chair notes, paragraph 118. R1-2606764, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606764.zip)
- Whether SSS is supported for the second stage remains FFS in the two-stage DCI physical-channel study. (R1-2606764, chair notes, paragraph 65. R1-2606764, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606764.zip; R1-2606764, chair notes, paragraph 70. R1-2606764, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606764.zip)
- The applicable cases for comb-2 and the maximum number of orthogonal DMRS ports for DFT-S-OFDM remain FFS. (R1-2606763, chair notes, paragraph 430. R1-2606763, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606763.zip)
- DMRS study details still include identifying spacing between every X-symbol group, whether exceptions apply, selecting L when multiple values are supported, and choosing among the three first-symbol location options. (R1-2606763, chair notes, paragraph 441. R1-2606763, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606763.zip)
What to watch next meeting
- At the next RAN1 meeting, watch how the container-size study handles the monitoring budget and whether the three sizing alternatives are combined or applied to different use cases. (R1-2606764, chair notes, paragraph 118. R1-2606764, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606764.zip)
- Watch for further work on comb-2 applicability, the DFT-S-OFDM DMRS port limit, and the unresolved DMRS spacing and location choices. (R1-2606763, chair notes, paragraph 430. R1-2606763, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606763.zip; R1-2606763, chair notes, paragraph 441. R1-2606763, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606763.zip)
- Watch whether the two-stage DCI study resolves SSS support for the second stage and develops the compared physical-channel options. (R1-2606764, chair notes, paragraph 65. R1-2606764, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606764.zip; R1-2606764, chair notes, paragraph 70. R1-2606764, 3GPP TSG RAN WG1 #126. https://www.3gpp.org/ftp/tsg_ran/WG1_RL1/TSGR1_126/Docs/R1-2606764.zip)
Sources
- R1-2606763 Session Notes of AI 10.5.2 (MIMO operation). Session record; register lists Ericsson as editor. Chair notes. Register status: endorsed at R1-126.
- R1-2606764 Session Notes of AI 10.5.4 (Downlink control channel, scheduling and HARQ operation). Session record; register lists NTT DOCOMO as editor. Chair notes. Register status: endorsed at R1-126.
- R1-2605869 Discussion on uplink transmission scheme(s) for uplink channels. NEC. Contribution. Register status: not treated at R1-126. No decision recorded in the register.
- R1-2605372 Transmission schemes and procedures for 6GR UL channels. InterDigital. Contribution. Register status: not treated at R1-126. No decision recorded in the register.
- R1-2606244 Discussion on downlink-based CSI acquisition. ETRI. Contribution. Register status: not treated at R1-126. No decision recorded in the register.
- R1-2605221 Discussion on aspects of downlink-based CSI acquisition for 6GR air interface. Futurewei. Contribution. Register status: not treated at R1-126. No decision recorded in the register.
- R1-2606507 Discussion on Aspects of downlink-based CSI acquisition. NTT DOCOMO. Contribution. Register status: not treated at R1-126. No decision recorded in the register.
- R1-2605723 On downlink-based CSI acquisition for 6GR. CATT. Contribution. Register status: not treated at R1-126. No decision recorded in the register.
- R1-2606109 Discussion on DL control channel and scheduling for DL/UL transmission. 1Finity. Contribution. Register status: not treated at R1-126. No decision recorded in the register.
- R1-2606334 Downlink control channel and scheduling for downlink and uplink transmission. InterDigital. Contribution. Register status: not treated at R1-126. No decision recorded in the register.
- R1-2606554 Discussion on downlink control channel, scheduling for downlink and uplink transmission. Quectel. Contribution. Register status: not treated at R1-126. No decision recorded in the register.
- R1-2605980 Discussion on downlink control channel and scheduling. Sony. Contribution. Register status: not treated at R1-126. No decision recorded in the register.
- R1-2605765 Discussion on downlink control channel and downlink/uplink scheduling. KT Corp.. Contribution. Register status: not treated at R1-126. No decision recorded in the register.
Coverage: RAN1 #126 (Maastricht, 2026-08-24 to 2026-08-28), agenda items 10.5.2.3, 10.5.3.1, 10.5.4.1. Scout read 19 recorded decisions and 129 company positions or contribution passages on these agenda items (catalog synced 2026-09-29) and cites 13 decisions and 12 positions from 13 TDocs. Every quoted passage was matched verbatim against the TDoc text; the summaries around the quotes are Scout's reading. Register statuses are copied from the 3GPP TDoc register: not treated means a document was not handled on its own, though its content may have fed feature-lead summaries or merged revisions. Not covered: other agenda items and meetings, plenary TDocs and plenary decisions after the meeting, email discussions after the meeting, and anything not yet in the chair notes or register.
- These are 6GR study-phase outcomes. The evidence pack contains no specification-change decision, so the study parameters here are not normative values.
- For downlink-based CSI acquisition, the supplied evidence contains company inputs marked not treated but no RAN1 acquisition-design decision.
Built by 3GPP Scout from the public meeting record (1772 TDocs registered, catalog synced 2026-09-29). Significance scores rank topics by decisions, contention, breadth and volume. Excerpts are at most 25 words and link to the original on the 3GPP file server.