R1-2601878
discussion
PUCCH-less 6GR
From Kyocera Corporation
Summary
Kyocera proposes a PUCCH-less uplink control architecture as a baseline for 6GR, where UCI (HARQ, CSI, SR) is conveyed via MAC CE on PUSCH when resources are available, and a minimized SR-replacement mechanism is used otherwise. Three proposals are made: adopting the PUCCH-less architecture, using PUSCH for UCI delivery, and studying CB-PUSCH-SR as the primary SR method for synchronized UEs with PRACH-SR as a fallback.
Position
Kyocera proposes a PUCCH-less uplink control architecture as a baseline study direction for 6GR, combining Option 2 (UCI carried on PUSCH) and Option 3 (other methods) to avoid permanent PUCCH configuration and persistent resource allocation. They propose that UCI (HARQ feedback, CSI reporting, and SR) be conveyed via MAC CE on PUSCH whenever uplink resources are available to the UE, unifying control with data and access signaling. For cases without scheduled uplink resources, they propose studying two SR-replacement mechanisms: CB-PUSCH-SR as the primary, low-latency mechanism for synchronized UEs using contention-based PUSCH-like common resource pools with open-loop power control and rapid retry, and minimized 2-step PRACH-SR as a robust fallback for unsynchronized or coverage-limited UEs using PRACH-based power control and preamble detection. They require that CB-PUSCH-SR and PRACH-SR operate in non-overlapping regimes based on uplink synchronization status, with implicit SR acknowledgement via MsgB reception or uplink grant within a configured response window.
Key proposals
- Proposal 1 (Sec Introduction): RAN1 should consider a PUCCH-less uplink control architecture as a baseline study direction for 6GR.
- Proposal 2 (Sec Introduction): RAN1 should consider UCI via MAC CE on PUSCH (HARQ, CSI, SR) when uplink resources are available to the UE.
- Proposal 3 (Sec SR Design Options): RAN1 should study both CB‑PUSCH-SR and PRACH‑SR, with the objective of identifying CB-PUSCH-SR as the primary mechanism when uplink synchronization exists and PRACH-SR as the fallback mechanism otherwise.
- Proposal 1 (Sec 6GR PUCCH-less UCI Architecture): RAN1 should consider a PUCCH-less uplink control architecture as a baseline study direction for 6GR.
- Proposal 2 (Sec 6GR PUCCH-less UCI Architecture): RAN1 should consider UCI via MAC CE on PUSCH (HARQ, CSI, SR) when uplink resources are available to the UE.
- Proposal 1 (Sec Conclusions): RAN1 should consider a PUCCH-less uplink control architecture as a baseline study direction for 6GR.
- Proposal 2 (Sec Conclusions): RAN1 should consider UCI via MAC CE on PUSCH (HARQ, CSI, SR) when uplink resources are scheduled to the UE.
- Proposal 3 (Sec Conclusions): RAN1 should study both CB‑PUSCH-SR and PRACH‑SR, with the objective of identifying CB-PUSCH-SR as the primary mechanism when uplink synchronization exists and PRACH-SR as the fallback mechanism otherwise.