R1-2508910
discussion
Channel coding study for 6G
From LG Electronics
Summary
This document contains 3 observations and 7 proposals from LG Electronics for 6G channel coding study. It covers LDPC code extensions including base graph modifications for higher throughput and inter-CB coding schemes (outer coding and GC-LDPC), as well as polar code extensions for larger UCI payloads.
Position
LG Electronics proposes studying modifications to the 5G NR LDPC base graph and puncturing patterns to improve decoding convergence at lower iteration regimes, presenting a modified BG1 with parity puncturing (puncturing first 2Z core parity nodes instead of information nodes) and a novel decoder initialization method that achieves significant gains at 2-15 iterations with a tradeoff of small performance loss at higher iterations. They propose studying inter-CB coding schemes including outer LDPC codes (showing up to 3dB gain over 5G NR at high-speed scenarios of 100-200km/h using BG1 without 2Z puncturing as outer code) and GC-LDPC codes with information-only coupling strategy to avoid dependency between local code rate and global parity bits. For polar codes, they propose studying enhancements to support UCI payloads larger than 1706 bits through a method that constructs an (N, K) polar code with N=2048 using the existing NR polar sequence of size 1024, achieving approximately 0.2dB gain over NR segmentation at 1% BLER, while also suggesting exploration of enhanced segmentation strategies as an alternative.
Key proposals
- Proposal 1 (Sec 2.1): Modifying or changing the base graph and the puncturing patterns of 5G NR LDPC codes can improve the error rate performance at lower number of decoding iterations.
- Proposal 2 (Sec 2.1): Study methods to improve decoding performance at lower iteration regime by keeping the 2Z or Z puncturing scheme in the base graph.
- Proposal 3 (Sec 2.1): Decision on simulation parameters for the comparison of different proposals for high throughput new base graph or modifications in current base graph, e.g., the range of code rates, the range of iteration and etc.
- Proposal 4 (Sec 2.2.1): Study LDPC codes as outer codes in 6GR.
- Proposal 5 (Sec 2.2.2): Study GC-LDPC codes as inter-CB coding scheme.
- Proposal 6 (Sec 3): Polar code enhancement can be considered as a topic for 6G channel coding study, including supports for large UCI payload.
- Proposal 7 (Sec 3): Study polar code enhancements to efficiently support larger payload sizes than 5G NR, while reusing the existing 5G NR polar sequences.