HARQ-ACK Codebook Adaptation for Overlapping PUCCH Transmissions
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Solution Overview
Problem
In wireless communication systems, particularly with the advent of 5G, there is a challenge in efficiently managing overlapping HARQ-ACK codebooks during transmissions, where priority is needed to ensure reliable and timely feedback, especially when multiple codebooks with different service requirements are scheduled within the same slot, leading to potential dropped codebooks due to overlapping transmissions.
Innovation Solution
A wireless transmit/receive unit (WTRU) is configured to prioritize HARQ-ACK codebooks based on service type and availability, allowing for partial or delayed transmission of dropped codebooks on non-overlapping PUCCH resources, using dynamic grants, and adapting codebooks by segregating them into sub-codebooks for transmission in subsequent slots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple HARQ-ACK codebooks are transmitted in the same slot, then the feedback coverage is improved, but the transmission reliability deteriorates due to overlapping transmissions
Solution Approach 1:
The patent segments a dropped HARQ-ACK codebook into multiple sub-codebooks (first sub-codebook and second sub-codebook). The first sub-codebook is transmitted in the current slot on non-overlapping PUCCH resources, while the second sub-codebook is transmitted in a subsequent slot. This segmentation resolves the contradiction by dividing the transmission across different time resources, ensuring reliable delivery without overlapping transmissions.
Solution Approach 2:
The patent introduces a time dimension by transmitting parts of the HARQ-ACK codebook in different slots. Instead of attempting to transmit all codebooks simultaneously in the same slot (spatial/temporal overlap), the solution distributes transmissions across multiple time slots, eliminating overlaps while maintaining comprehensive feedback coverage.
2Loss of time
If HARQ-ACK codebook transmission is prioritized, then the feedback timeliness is improved, but the resource usage efficiency deteriorates due to potential drops of lower priority codebooks
Solution Approach 1:
The patent transmits the first sub-codebook in the current slot before the subsequent slot transmission of the second sub-codebook. This preliminary action ensures that critical feedback is delivered timely while preserving the opportunity to transmit remaining feedback in the future, balancing timeliness with completeness.
Solution Approach 2:
The patent effectively discards the transmission of the second sub-codebook in the current slot (when it would overlap) and recovers it by transmitting in a subsequent slot. This approach prioritizes timely transmission of the first sub-codebook while recovering the deferred feedback information later, maintaining both timeliness and completeness.
3Adaptability or versatility
If PUCCH resources are used for dropped codebook transmission, then the transmission flexibility is improved, but the resource availability deteriorates due to overlapping PUCCH transmissions
Solution Approach 1:
The patent dynamically selects PUCCH resources for transmitting the first sub-codebook based on non-overlapping criteria. The resource selection adapts to the transmission scenario, choosing resources that do not conflict with other simultaneous transmissions. This dynamic resource allocation maintains flexibility while avoiding the complexity of managing overlapping transmissions.
Data Source
AI summary
Systems, methods, and instrumentalities are disclosed that may be associated with HARQ-ACK codebook adaptations. A WTRU) may be configured with multiple physical uplink channels, e.g., physical uplink control channels (PUCCHs), in a slot. Each physical uplink channel may have a respective HARQ-ACK codebook. In examples, the WTRU may determine that a first physical uplink channel and a second physical uplink channel overlap in a slot. In such a case, the WTRU may determine that a first HARQ-ACK codebook associated with the first physical uplink channel has a higher priority than a second HARQ-ACK codebook associated with the second physical uplink channel. The WTRU may transmit the first HARQ-ACK codebook on the first physical uplink channel in the slot. The WTRU may send part of the second HARQ-ACK codebook in the slot and part of the second HARQ-ACK codebook in a subsequent slot (e.g., a next slot, a future slot, etc.).