R1-2508640
discussion
Views on Channel Coding for 6GR
From AT&T
Summary
AT&T presents 19 proposals and 11 observations on channel coding for 6GR, advocating for reuse of NR LDPC and Polar codes under existing NR conditions while seeking precise characterization of 'NR range' before studying any extensions beyond it. The document opposes introducing different coding schemes per throughput regime and argues that channel coding study should focus on complexity, reliability, and migration efficiency rather than peak data rates, which it considers a RAN plenary issue.
Position
AT&T opposes introducing different channel coding schemes for different throughput regimes for DL-SCH, arguing this would require the network to activate multiple channel coding modules prior to link adaptation-based throughput identification, causing energy and complexity inefficiency at the network side. They require precise characterization of the 'NR range' notion—specifically dependent on both block length and code rate—before any agreement on channel coding extensions can proceed, proposing this be provided at RAN1#123. AT&T proposes reusing NR LDPC codes and NR Polar codes for 6GR data and control channels under the same NR conditions on code rate and code block length, with enhancements beyond the NR range limited to critical performance, complexity, and migration issues; otherwise they prefer straightforward extensions via code block concatenation/segmentation over new channel code designs. They argue that discussion on target peak data rates for 6GR is a RAN plenary issue, not RAN WG1, and that most data rate improvements come from modulation order and layer packing, not channel coding gains given NR already supports up to ~0.93 code rate.
Key proposals
- Proposal 1 (Sec 2): Maintaining NR channel code types in 6GR is feasible while preserving the design principle of enabling full 6G performance via 5G-capable RAN infrastructure.
- Proposal 4 (Sec 2): Precise characterization of the 'NR range' is needed to move forward with an agreement on channel coding reuse.
- Proposal 5 (Sec 2): Precise characterization of 'NR range' notion used in the agreement for channel coding is to be provided in RAN1#123.
- Proposal 7 (Sec 2): Reuse NR LDPC codes and NR Polar codes for 6GR data channel(s) and 6GR control channel(s), respectively, at least under the same NR conditions on code rate and code block length.
- Proposal 8 (Sec 2): For new code rate/code block combination region(s) beyond NR values, AT&T is open to discuss potential enhancements if they address critical performance, complexity, and migration issues.
- Proposal 9 (Sec 2): If enhancement criteria are not met, prefer reusing NR channel coding with straightforward extensions (e.g., code block concatenation/segmentation) rather than new designs with marginal gains or deployment complications.
- Proposal 10 (Sec 2): Proposed enhancements for 6GR channel coding beyond the NR range should only address critical issues related to performance, complexity at both network and device side, and migration from NR to 6GR.
- Proposal 11 (Sec 2): AT&T does not support channel coding selection based on a performance regime, citing inefficient network operation from activating multiple coding modules prior to link adaptation.
- Proposal 12 (Sec 2): AT&T does not support introducing different channel coding schemes for different throughput regimes for DL-SCH.
- Proposal 13 (Sec 2): LDPC base graph selection based on data rate regimes for DL-SCH is not supported in 6GR.
- Proposal 14 (Sec 3): Discussion on target peak data rates for 6GR is not a RAN WG1 related issue and should be discussed in RAN plenary meetings.
- Proposal 15 (Sec 3): The channel coding study for both data and control channels should focus on improvements in complexity, reliability and migration efficiency with respect to NR incumbent networks.
- Proposal 17 (Sec 3): Reuse NR LDPC codes and NR Polar codes for 6GR data channel(s) and 6GR control channel(s), respectively, at least under the same NR conditions on code rate and code block length.
- Proposal 18 (Sec 3): Proposed enhancements for 6GR channel coding beyond the NR range should only address critical issues related to performance, complexity at both the network side and the device side, as well as consider the potential migration needed from NR to 6GR deployment.
- Proposal 19 (Sec 3): LDPC base graph selection based on data rate regimes for DL-SCH is not supported in 6GR.