R1-2600154
discussion
Downlink control information and data scheduling
From Huawei
Summary
This 3GPP RAN1 contribution from Huawei/HiSilicon presents 22 proposals and 2 observations addressing 6G downlink control information and data scheduling. Key areas include introducing a two-stage DCI structure, joint multi-carrier scheduling, energy-saving enhancements, and adapting scheduling design for new services like AI/ML and immersive communications.
Position
Huawei proposes studying a two-stage DCI structure to mitigate PDCCH blocking, where a fixed-size 1st-stage DCI schedules a variable 2nd-stage DCI carrying DL/UL scheduling information, aiming to eliminate blind decoding for the 2nd-stage DCI. They propose studying dynamic PDCCH-based indications for flexible BS and UE active duration control, including early termination of Cell DTX/DRX active duration, rather than relying solely on semi-static C-DRX configuration. For multi-carrier scheduling, they propose further studying enhanced single-DCI mechanisms and two-stage DCI approaches to reduce control overhead, arguing that semi-statically reserving fields for the maximum number of schedulable carriers creates resource inefficiency. They propose that scheduling design jointly considers new service requirements such as unequal error protection for data with different importance characteristics (e.g., AI/ML modalities, immersive video streams) and predicted data arrival with critical PDB. They support retaining NR's in-order scheduling restrictions as baseline and studying early termination for PDSCH repetitions to improve spectral efficiency when CSI is inaccurate.
Key proposals
- Proposal 1 (Sec 2.2.1): RAN1 should study two-stage DCI for L1 DL control information, where the 1st-stage DCI provides the information scheduling the 2nd-stage DCI, and the 2nd-stage DCI provides the information for DL and UL scheduling.
- Proposal 2 (Sec 2.2.2): Study PDCCH based indication mechanism to enable flexible BS and UE sleep opportunity, including dynamic control of active duration.
- Proposal 3 (Sec 2.2.3): Further study enhanced mechanisms for single DCI jointly scheduling multi-carriers in 6GR to reduce control overhead and enable more efficient resource utilization.
- Proposal 5 (Sec 2.2.4): Further study the impact to the DCI design considering the flexible DL and UL pairing in 6GR.
- Proposal 6 (Sec 3.1.1): The design for scheduling in 6G Day 1 should jointly consider coverage enhancement, flexible BWP bandwidth adjustment, advanced multi-carrier operation, DL/UL carrier decoupling and switching, flexible duplex mechanisms, etc.
- Proposal 7 (Sec 3.1.2): 6GR scheduling design should consider new requirements from new services such as AI/ML and immersive communications.
- Proposal 9 (Sec 3.2.1.1): Study signaling aspects on TDRA, by jointly considering slot/mini-slot scheduling within or across the slot, PxSCH repetitions, UL TB mapping on multiple slots, SBFD, etc.
- Proposal 10 (Sec 3.2.1.1): The framework combining a pre-defined or RRC configured TDRA table with DCI indication can be the baseline.
- Proposal 12 (Sec 3.2.1.2): Study signaling aspects on FDRA, by jointly considering features of wider bandwidth, BWP/carrier switch, SBFD, etc.
- Proposal 14 (Sec 3.2.1.3): Study independent MCS indications for multiple transmissions on different sub-bands within a carrier.
- Proposal 15 (Sec 3.2.1.3): Study new transmission and retransmission simultaneously in one slot on a carrier.
- Proposal 17 (Sec 3.2.2): Study basic scheduling operations including TBS determination, indication rules of MCS, NDI and RV for (re)transmission, etc.
- Proposal 18 (Sec 3.2.3): Support to keep the restrictions on the in-order scheduling operations.
- Proposal 20 (Sec 3.2.4): Study enhancement for PDSCH repetitions, including an early termination mechanism, and different resource allocations for different repetitions.
- Proposal 21 (Sec 3.2.5): Study unequal protection for data with different importance characteristics.