R1-2601919
discussion
Discussion on Channel Coding for Small Block Lengths
From EURECOM
Summary
EURECOM argues that 5G NR Reed-Muller (RM) codes are suboptimal for small UCI payloads and proposes studying novel DMRS-less transmission schemes using vertical-horizontal coding (VHC) for superior coverage, performance, and PAPR. The document presents 6 observations and 1 proposal, showing up to 3dB SNR gain and 6.6dB PAPR reduction over legacy PUCCH Format 3.
Position
EURECOM presents a technical case against the 5G NR Reed-Muller (RM) code baseline for small block lengths, arguing its performance is far from optimal and that significant room for improvement exists. They propose studying novel encoding/modulation schemes, specifically advocating for DMRS-less transmission using a vertical and horizontal coding (VHC) product-code strategy. They argue that DMRS overhead (up to 28% in PUCCH Format 3) introduces significant sub-optimality for short block lengths, and that DMRS-less designs offer significant performance gains and PAPR reduction (up to 6.6dB at 1% outage). They also argue that the proposed VHC scheme achieves low receiver complexity by separating detection in time and frequency domains.
Key proposals
- Proposal 1 (Section: Introduction/Conclusion): Study novel encoding/modulation schemes for transmission of short packages.
- Observation 1 (Section: Introduction/Conclusion): Coverage enhancement is one of the key KPIs in 6G. Previous studies of coverage enhancements showed that significant performance improvements in the transmission of small UCI payloads are possible.
- Observation 2 (Section: Introduction/Conclusion): The performance of 3GPP RM codes is far from optimal and there is significant room for improvement.
- Observation 3 (Section: Introduction/Conclusion): For short block lengths, DMRS introduce a significant amount of sub-optimality and potential novel coding strategies should aim to reduce this overhead.
- Observation 4 (Section: Introduction/Conclusion): The proposed transmission scheme has low complexity because detection in time and frequency domain can be efficiently separated.
- Observation 5 (Section: Introduction/Conclusion): DMRS-less transmission schemes provide significant room for PAPR reduction.
- Observation 6 (Section: Introduction/Conclusion): Simulations of novel coding strategies in UCI transmission show significant performance improvements over NR RM Codes.