HARQ-ACK Feedback Position Determination for Repeated PDSCH
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Solution Overview
Problem
The semi-static HARQ-ACK codebook is not applicable to scenarios where the same PDSCH is transmitted repeatedly in time domain in one slot for multiple times, leading to incomplete feedback due to the absence of candidate PDSCH reception occasions.
Innovation Solution
A method to determine the feedback position of HARQ-ACK by configuring or indicating a repetition scheme of PDSCH in one slot, using a start and length indicator (SLIV) of time domain resource allocation (TDRA) to identify candidate PDSCH reception occasions, and then determining the feedback position based on downlink control information (DCI) and the preset HARQ-ACK codebook.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a semi-static HARQ-ACK codebook is used for normal PDSCH transmission, then the codebook structure is simple and easy to implement, but it cannot accommodate repeated PDSCH transmissions in one slot leading to incomplete feedback
Solution Approach 1:
The patent segments the HARQ-ACK codebook into multiple candidate PDSCH reception occasions, where each occasion corresponds to a potential PDSCH transmission time. This segmentation allows the codebook to accommodate repeated PDSCH transmissions within a slot by creating distinct feedback positions for each transmission occasion, thereby resolving the contradiction between adaptability and complexity.
Solution Approach 2:
The patent pre-determines candidate PDSCH reception occasions based on time domain resource allocation (TDRA) information before actual PDSCH transmission occurs. By preliminarily identifying potential reception occasions and their corresponding feedback positions, the system prepares the HARQ-ACK codebook structure in advance to handle repeated transmissions, maintaining codebook simplicity while improving adaptability.
2Reliability
If the semi-static HARQ-ACK codebook is extended to include all possible PDSCH reception occasions, then feedback completeness is improved, but the codebook size increases leading to longer feedback timing
Solution Approach 1:
The patent applies local quality by creating candidate PDSCH reception occasions only for specific time domains where PDSCH transmission is actually scheduled or expected. Instead of uniformly expanding the codebook for all possible occasions, the system locally adapts the codebook structure to match actual transmission patterns, ensuring feedback completeness without unnecessarily increasing codebook size or timing duration.
Solution Approach 2:
The patent dynamically determines the number and positions of candidate PDSCH reception occasions based on actual PDSCH transmission configurations. The HARQ-ACK codebook structure is dynamically adjusted to include only the necessary number of feedback positions corresponding to actual transmissions, preventing fixed over-expansion that would increase feedback timing while ensuring reliability for repeated transmissions.
Data Source
AI summary
The present disclosure provides a hybrid automatic repeat request-acknowledgement (HARQ-ACK) feedback position determining method and a communications device. The HARQ-ACK feedback position determining method includes: when a repetition scheme of a physical downlink shared channel (PDSCH) in one slot is configured or indicated, determining at least one candidate PDSCH reception occasion based on a start and length indicator (SLIV) of a time domain resource allocation (TDRA); and determining, based on the first PDSCH scheduled by using downlink control information (DCI) and the at least one candidate PDSCH reception occasion, a feedback position of an HARQ-ACK corresponding to a first PDSCH in a preset HARQ-ACK codebook, where the first PDSCH is transmitted for one or more times.