HARQ Feedback Codebook Determination for Dummy PUSCH Overlap
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Solution Overview
Problem
Current 5G wireless communication systems face challenges in dynamically scheduling resources for HARQ feedback, particularly when dummy PUSCH channels overlap with PUCCH channels, leading to restrictions on subsequent PDSCH scheduling and uncertainty in determining the number of HARQ feedback bits.
Innovation Solution
The proposed solution allows the base station to continue dynamically scheduling PDSCH after a UL grant for a dummy PUSCH, and the UE determines the number of HARQ feedback bits based on the last DL grant's DAI, removing scheduling restrictions and ensuring accurate feedback codebook size determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the system schedules PDSCH with HARQ-ACK overlapping with dummy PUSCH, then resource utilization improves, but feedback codebook determination becomes uncertain
Solution Approach 1:
The base station sends a grant message in advance to allow transmission in a future time slot, preparing the uplink resource before the actual transmission occurs. This preliminary scheduling enables the system to reserve resources proactively, improving overall resource utilization while maintaining clear feedback mechanisms.
Solution Approach 2:
The patent introduces a feedback codebook determination mechanism that uses the last received grant's DAI value as an intermediary to resolve the uncertainty. This intermediary element bridges the gap between overlapping PDSCH scheduling and dummy PUSCH transmission, allowing the UE to accurately determine the feedback codebook size even when resources overlap.
2Adaptability or versatility
If the system allows dynamic PDSCH scheduling after dummy PUSCH grant, then scheduling flexibility improves, but HARQ-ACK feedback accuracy deteriorates
Solution Approach 1:
The system dynamically adjusts the feedback codebook determination based on the timing relationship between grants and acknowledgments. When a grant for dummy PUSCH is received, the system dynamically identifies this as the reference point for codebook size determination, allowing flexible scheduling while maintaining accurate feedback through adaptive reference selection.
Solution Approach 2:
The patent implements a feedback mechanism where the UE determines the HARQ-ACK codebook size based on the DAI value in the last received grant. This feedback loop ensures that even with dynamic scheduling flexibility, the acknowledgment accuracy is maintained by continuously referencing the most recent grant information.
3Measurement precision
If the system forbids PDSCH scheduling when HARQ-ACK overlaps with non-dummy PUSCH, then feedback accuracy improves, but resource efficiency deteriorates
Solution Approach 1:
The patent applies different scheduling rules to different types of PUSCH channels. For dummy PUSCH, the system allows overlapping PDSCH scheduling with specific feedback determination rules. For non-dummy PUSCH, traditional restrictions apply. This localized differentiation maintains feedback accuracy where needed while improving resource efficiency where possible.
Data Source
AI summary
In one aspect a wireless communications method includes sending, from a first radio terminal to a second radio terminal, a grant message to allow transmission in a future time slot, wherein the future timeslot corresponds to resources of a dummy shared channel in a first direction, and scheduling one or more resources of a shared channel in a second direction with corresponding acknowledgement that overlaps in time with the dummy shared channel in the first direction. In another aspect, a method includes receiving, at a second radio terminal from a first radio terminal, a grant message to allow transmission in a future time slot, wherein the future timeslot corresponds to resources of a dummy shared channel in a first direction, and receiving one or more resources of a shared channel in a second direction with corresponding acknowledgement that overlaps in time with the dummy shared channel in the first direction.