It should be noted, however, that the foundations for 6G were laid long before RAN1#122. Significant research has already been carried out in projects such as HEXA-X, HEXA-X II, 6G Flagship (Finland), EU Horizon projects like 6G-SANDBOX, 6G BRAINS, and REINDEER, 6G-SHINE in China, etc. Within 3GPP itself, companies began aligning their 6G directions officially in March 2025 at the first 6G workshop.
Before RAN1 began its dedicated 6G study, the RAN plenary initiated a high-level investigation into 6G scenarios and use cases (RP-243327). The results of that effort will be captured in TR 38.914, serving as the 6G counterpart to the Rel-14 TR 38.913 for 5G NR.
The scope of the 6G Study Item (SID) is defined in RP-251881 (“New SID: Study on 6G Radio”), and the associated work plan is described in R1-2506303.
In future posts, I plan to collect and summarize all RAN1 agreements related to the 6G study on a dedicated page.
6G at RAN1#122 meeting
The first 6G discussions in RAN1 took place at RAN1#122, held from August 22–26, 2025, in Bangalore, India. The agenda grouped 6G work items into dedicated topics (see full agenda in R1-2505100). In addition to the key 6G topics summarised in the sections below, some of the most central topics will only begin in later meetings, starting with RAN1#124 in February 2026. The workflow for each agenda item (AI) followed a common structure. Feature Leads (FLs) were appointed to summarize submitted technical documents (TDocs), lead offline discussions, and prepare draft agreements. During online sessions, selected TDocs were presented (chosen via voting; see Excel list), allowing companies to highlight their key proposals and trigger further debate.Offline discussions gave companies space to refine the FLs’ draft agreements. These were then brought back to the online sessions, where they were further discussed, revised, and ultimately captured in the official chair notes.
At this early stage, the agreements should not be seen as final decisions. Instead, they serve as guidance and orientation points for structuring future discussions.
11.1 Overview
The FL summary is: R1-2506618Study a scalable 6GR design for diverse device types, considering aspects:
- What should be commonly applicable to all 6G device types
- FFS: add-on features dedicated to specific device types, if any
- Study the device types from physical layer perspective to be supported by 6GR, subject to further discussion and confirmation in RAN
- For the study of RAN1 6GR design, consider the minimum spectrum allocation in which 6G can operate, subject to further discussion and confirmation in RAN.
- On enhanced overall coverage, identify coverage target(s) considering diverse use cases and device types
- Identify the high-level aspects which impact on the 6GR sync signal structure and associated periodicity.
- Identify the high-level aspects which impact on the NR-6GR MRSS support
- Including the lessons learned from LTE-NR DSS
- Study and identify the lessons learned from NR BWP framework
- Study and identify the lessons learned from NR spectrum utilization and aggregation framework
Note: MRSS aspects are separate discussion
Study the following smallest maximum supported RF and BB UE BW without spectrum aggregation for at least one low-tier device type supported by 6GR framework from physical layer perspective, subject to further discussion and confirmation in RAN
- Opt1: 3MHz
- Opt2: 5MHz
- Opt3: 10MHz
- Opt4: 20MHz
- FFS: the UL bandwidth may be different to the DL bandwidth
- FFS: the bandwidth value may be different for different SCS, duplex modes, and bands.
- FFS: whether RF and BB UE BW are same or different
- Study and identify the lessons learned from NR duplex modes
- On 6GR duplexing study, RAN1 considers at least following duplex types
- FD-FDD
- Semi-static TDD
- gNB semi-static SBFD
- HD-FDD on UE side
- Dynamic TDD
- Study whether to consider following duplexing types
- gNB dynamic SBFD
- UE SBFD
- gNB FD
- For harmonized 6GR design for TN and NTN, RAN1 studies to identify the technical aspects affected by NTN characteristics, as well as lessons learned from NR/IoT NTN.
11.2 Evaluation assumptions
The FL summary is: R1-2506581- The deployment scenarios in TR38.914 should be considered for evaluation assumption
- The common evaluation assumptions including the antenna modelling, general system-level simulation assumptions (including the carrier frequency, bandwidth and subcarrier spacing used for link-level simulation) for the deployment scenarios in TR38.914, link budget and traffic models will be discussed in AI 11.2
- Other assumptions including for link-level simulation specific to each technical topic will be separately discussed under each individual agenda.
- Note: Subcarrier spacing decision is up to AI 11.3.2.
Conclusion
- Template in R1-2506582 is to be used for collecting inputs from companies.
- Additional NTN or TN assumptions, if any, or any necessary change of the parameters, are to be incorporated into the updated one of R1-2506582.
- Study which of the following traffic models are to be used for 6G evaluations, e.g.,
- Full buffer
- FTP Model 1 (in TR 36.814)
- FTP Model 2 (in TR 36.814)
- FTP Model 3 (in TR 36.872)
- XR Traffic models (in TR 38.838)
- VoIP model (as in TR 36.814)
- Instant message (as in TR 38.840)
- Study whether to introduce the following traffic models for 6G evaluations considering, e.g.,
- FTP-3 variant with packet delay budget requirement
- Details FFS
- New traffic model considering a mixed/variable packet size and the associated time domain behaviors (e.g., time between adjacent packet arrivals, packet delay budget)
- Details FFS
- New traffic model(s) considering the new use cases or services, e.g., AI/ML services, immersive communication services, etc.
- Details FFS
- FTP-3 variant with packet delay budget requirement
- Study whether to introduce new/additional approaches that can reflect the impact of bidirectional traffic flows on performance metrics (e.g., impact of UL TCP ACK latency on DL throughput/latency)
- Note: Whether/how to consider the combination of traffic model and loading level will be studied under individual agendas.
11.3 Waveform and frame structure for 6GR air interface
11.3.1 Waveform
The FL summary is: R1-2506595CP-OFDM and DFT-s-OFDM waveforms as defined in 5G NR are supported as the basis for 6GR for uplink
- Enhancements/modifications on CP-OFDM/DFT-s-OFDM will be studied as potential additions
- Other OFDM based waveforms are not precluded.
CP-OFDM waveform as defined in 5G NR is supported as the basis for 6GR for downlink
- Enhancements/modifications on CP-OFDM will be studied as potential additions
- DFT-s-OFDM or any other OFDM-based waveform will be studied as a potential additional waveform for downlink
Proponents are encouraged to provide more detailed information on their proposals for the next meeting, e.g.:
- Targeted link direction, i.e. DL, UL or both
- Targeted use case (e.g. NTN, specific frequency range, etc.), if any
- Potential motivations metrics used, and quantified gains for a proposal, e.g.
- Coverage
- Network energy efficiency
- UE energy efficiency
- Spectral efficiency
- High speed tolerance
- Scheduling flexibility
- Integration with ISAC
- MRSS compatibility
- Target channels/signals, e.g. all channels, PxSCH only, etc.
- MIMO (SU and MU-MIMO) compatibility
- Target modulations, and impact to other modulations, if applicable
- Multi-user multiplexing/scheduling flexibility
- Multiplexing/coexistence with baseline waveforms
- Impact on synchronization and initial access
- Expected specification impact
- Transmitter/receiver complexity and impact to power consumption.
In general, a number of alternative or enhanced waveforms were proposed in the TDocs, such as:
For Uplink (UL):
- Enhanced DFT-s-OFDM (e.g., with frequency domain spectrum shaping / FDSS, spectrum extension, or multi-layer extensions) – improves coverage and reduces PAPR.
- Filtered / windowed OFDM variants (e.g., f-OFDM, W-OFDM) – for better out-of-band emission (OOBE) control.
- CE (Constant Envelope)-OFDM, FM (Filtered Multitone)-OFDM, BS (Band-Swep)-OFDM – advanced OFDM-based candidates to address specific KPIs like energy efficiency or Doppler robustness.
- Low-PAPR techniques (precoding, spectrum shaping, etc.) – targeted to NTN or cell-edge scenarios.
- DL DFT-s-OFDM – proposed by multiple companies for better coverage in IoT or NTN cases.
- Filtered OFDM (F-OFDM) – reduces OOBE and supports forward compatibility with mixed services
- Other OFDM-based enhancements (e.g., applying windowing or precoding to CP-OFDM) – to improve robustness in high-mobility or wideband deployments.
- OTFS (Orthogonal Time Frequency Space, incl. Zak-OTFS) – positioned by some as more robust to high-Doppler and potentially beneficial for ISAC (communication + sensing).
- Orthogonal Sequence Division Multiplexing (OSDM) – studied as another alternative structure for DL.
11.3.2 Frame structure
The final version of the feature lead summary is R1-2506604, but it is currently unavailable. The latest version is R1-2506603.- 6GR takes the following SCS as start point for discussion for all the signals/channels except PRACH.
- For sub 6GHz
- The following subcarrier spacing is at least supported
- 15kHz SCS for FDD, 30kHz SCS for TDD
- FFS: 30kHz SCS for FDD for around e.g., 1-2.5GHz
- FFS: 7.5kHz SCS for sub1GHz (FDD)
- Whether to discuss the FFS will be subject to RANP decision.
- The following subcarrier spacing is at least supported
- For around 7GHz
- The following subcarrier spacing options can be studied
- 30kHz, 60kHz
- The following subcarrier spacing options can be studied
- FFS: For around 15GHz
- The following subcarrier spacing options can be studied
- 30kHz, 60kHz, 120kHz
- Whether to discuss it will be subject to RANP decision
- The following subcarrier spacing options can be studied
- For between 24.25GHz - 52.6GHz
- Subcarrier spacing 120kHz is supported
- FFS whether to allow using additional subcarrier spacing for SSB
- For sub 6GHz
- FFS subcarrier spacing for PRACH and up to initial access discussion.
Numerologies for sensing is up to sensing agenda discussion.
- 6GR supports normal cyclic prefix, i.e., same as the normal CP defined in NR.
- FFS potential need for other CP
11.4 Channel coding and modulation for 6GR interface
11.4.1 Channel coding
The FL summary for control channel coding is: R1-2506611.The FL summary summary for data channel coding is: R1-2506590
For 6GR control channel coding,
- Evaluations can be provided in form of BLER and FAR results.
- Evaluations/analysis can be provided for complexity, decoding latency,
- Other metrics are not precluded.
- Proponent companies to provide evaluation assumptions and methodologies for respective evaluation.
- Proponent companies to provide details of channel coding extension compared with NR channel coding
- Proponent companies to provide justification for the channel coding extension, compared with control channel codes as defined in 5G NR.
For 6GR data channel coding,
- Evaluations can be provided in form of BLER results.
- Evaluation/analysis on throughput, complexity, and decoding latency can be provided
- Other metrics are not precluded.
- Proponent companies to provide their target scenarios and requirements, evaluation assumptions and methodologies for respective evaluation/analysis, e.g., decoding algorithm and details, information sizes, code rates, HARQ scheme, channel type, modulation order, target BLER, etc.
- Proponent companies to provide details of channel coding extension compared with NR channel coding.
- Proponent companies to provide justification for the channel coding extension, and how to satisfy 6G requirements and characteristics with acceptable performance/complexity trade-off, compared with data channel codes as defined in 5G NR.
In summary, most companies want to keep LDPC (data) and Polar (control) as the baseline. Extensions to LDPC (new base graphs, higher parallelism, larger lifting sizes) are the most likely evolution. Extensions to Polar may be considered if larger control payloads are proven necessary. Completely new schemes are not seriously on the table at this stage.
11.4.2 Modulation, joint channel coding and modulation
The FL summary is: R1-2506579- For 6GR DL, 5G NR uniform QPSK, 16QAM, 64QAM, 256QAM and 1024QAM are supported as basis for study for data channel
- FFS: Enhancements and other modulation schemes
- For 6GR UL, 5G NR uniform QPSK, 16QAM, 64QAM, and 256QAM are supported as basis for study for CP-OFDM for data channel
- FFS: Enhancements and other modulation schemes
- For 6GR UL, 5G NR pi/2 BPSK, uniform QPSK, 16QAM, 64QAM, and 256QAM are supported as basis for study for DFT-s-OFDM for data channel
- FFS: Enhancements and other modulation schemes
Joint Modulation and Coding (JMC) is not part of the current agreement, but several companies proposed it as a longer-term study item. JMC aims to go beyond the traditional 5G Bit-Interleaved Coded Modulation (BICM) framework by jointly designing coding and modulation (e.g., multilevel coding, trellis-coded modulation, probabilistic shaping + coding, or iterative detection/decoding). The potential benefits are better spectral efficiency, unequal error protection, and improved performance for high-order QAM, but this comes at the cost of higher complexity and implementation challenges.
11.5 Energy efficiency
The final feature lead summary should be R1-2506602, but the latest available one is: R1-2506601.Study how to reuse and update reference configurations in TR 38.864 for 6G BS.
Study how/whether to reuse or update the power model in TR 38.864 for evaluating BS power consumption for 6G BS.
- Study metric(s) for UE energy efficiency.
- Study metric(s) for BS energy efficiency.
Study reference configurations and power consumption model for 6G UE, considering but not restricted to the following:
- TR 38.840 (UEPS), TR38.875 (RedCap), TR38.865 (eRedCap), and TR38.869 (LP-WUS/WUR) for reference configurations
- TR 38.840 (UEPS), TR38.875 (RedCap), and TR38.869 (LP-WUS/WUR) for power consumption models
- Study baseline BS setting(s) for evaluating 6G BS EE improvement/impact, considering NR features and 6G BS reference configuration(s)
- Study baseline UE setting(s) for evaluating 6G UE EE improvement/impact, considering NR features and 6G UE reference configuration(s)
11.6 AI/ML in 6GR interface
The FL summary is: R1-2506456.For 6GR AI/ML use cases identification/categorization, for each (sub-)use case proposed, proponent companies are encouraged to study and report the following:
- Definition of each (sub-)use case, including at least AI/ML model input/output
- The evaluation assumption, methodology, KPIs, benchmark, and preliminary simulation results
- Assumption on training types, e.g.,
- offline training, online training/finetuning
- Label construction (if applicable), including whether/how to obtain label data for model training
- Assumption on model location for inference, e.g., UE-sided model, NW-sided model, and two-sided model
- Collaboration/interaction between UE and NW, e.g.,
- no collaboration/interaction
- UE/Network collaboration targeting at separate or joint ML operation
- High level potential specification impact
The most popular / frequently highlighted AI/ML use cases by the companies for 6G radio (6GR) are:
- AI/ML Receivers (Neural Receivers)
- Use ML models to replace or enhance classical receiver blocks (channel estimation, equalization, detection).
- Goal: better performance under high interference, extreme MIMO, and mobility conditions.
- Reference symbol (DMRS) design with neural receivers – AI/ML receivers may allow more flexible or sparse DMRS patterns, reducing pilot overhead while maintaining reliable channel estimation, especially in wideband/high-antenna scenarios
- Beam Management
- Already studied in Rel-18/19 for 5G-A, carried forward to 6G:
- Intra-cell beam prediction (spatial and temporal).
- Inter-cell beam prediction (new in 6G, predicts beams across multiple cells).
- Tx-Rx beam pair prediction (joint prediction to reduce delay in beam activation).
- Beam prediction with continuous learning (adapts beam decisions in real time).
- Widely seen as a front-runner for early normative work.
- Already studied in Rel-18/19 for 5G-A, carried forward to 6G:
- CSI Feedback Enhancements
- CSI Prediction (UE-sided model) – studied in Rel-19.
- CSI Compression (two-sided model) – ongoing in 5G-A Rel-20, strong candidate for 6G baseline.
- Use AI/ML to reduce feedback overhead while improving accuracy.
- RS design enhancements for CSI feedback – AI/ML-assisted CSI reporting may enable more adaptive or reduced-density reference signal designs, lowering overhead while preserving accurate channel state representation for both prediction and compression tasks.
- Positioning
- Explored in Rel-18/19 with multiple variants (UE-sided direct positioning, NG-RAN/LMF-assisted).
- Still relevant but not seen as a first-priority 6G use case; may come later.
- Continuous Learning (CL) Use Cases)
- A new area for 6G: models adapt online to changing network/user conditions.
- Applies to many functions: beam selection, mobility management, power control, MCS selection.
- Strongly emphasized as essential for “AI-native” air interface.
Other AIs
Once the initial discussions on the topics above have matured, the study will continue in 2026 with the other core 6G topics:- 11.7 Initial Access
- 11.8 MIMO operation
- 11.9 Physical-layer control, data scheduling, and HARQ
- 11.10 Duplexing
- 11.11 Spectrum utilization and aggregation
- 11.12 NTN
- 11.13 Other physical-layer signals, channels, and procedures
- 11.14 Sensing
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