HARQ-ACK Feedback Delay for SPS PDSCH Overlaps
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Solution Overview
Problem
In wireless communications systems, particularly in new radio (NR), the reporting of acknowledgement feedback for semi-persistent scheduled (SPS) physical downlink shared channel (PDSCH) often overlaps with downlink or flexible symbols, leading to resource waste and misunderstanding between the user equipment (UE) and the network due to missed HARQ-ACK reports.
Innovation Solution
The UE determines conditions for delaying or canceling the HARQ-ACK feedback based on overlaps with downlink or flexible symbols, thereby avoiding resource waste and misunderstanding by making informed decisions on when to transmit or delay the feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the UE transmits HARQ-ACK feedback in the scheduled slot, then the feedback is reported timely, but resource waste and misunderstanding occur when the slot overlaps with downlink or flexible symbols
Solution Approach 1:
The patent applies dynamics by making the HARQ-ACK feedback transmission flexible rather than static. The UE dynamically determines whether to transmit, delay, or cancel HARQ-ACK feedback based on the actual overlap condition between the scheduled slot and downlink/flexible symbols. This dynamic adaptation resolves the contradiction by allowing timely feedback when possible while preventing unreliable transmission when overlap occurs.
Solution Approach 2:
The patent uses feedback mechanisms where the UE monitors the slot configuration and feedback conditions, then adjusts HARQ-ACK transmission accordingly. The network entity also provides feedback through slot format indicators that inform the UE about the direction of symbols, enabling coordinated decision-making to avoid resource waste while maintaining reliable feedback reporting.
2Loss of energy
If the UE delays or cancels HARQ-ACK feedback to avoid overlap, then resource waste is minimized, but the feedback timing becomes uncertain and may require retransmissions
Solution Approach 1:
The patent introduces an intermediary mechanism through the network entity's slot format indication and the UE's conditional determination logic. This intermediary layer mediates between the conflicting requirements of resource efficiency and communication efficiency by providing structured rules for when to delay or cancel feedback, preventing arbitrary decisions that would harm productivity while avoiding resource waste through intelligent suppression of unnecessary transmissions.
Solution Approach 2:
The patent changes the parameter of feedback transmission timing based on the overlap condition. Instead of fixed timing, the system adjusts the transmission parameter dynamically - transmitting at the scheduled time when no overlap exists, delaying to a later uplink slot when overlap occurs, or canceling when appropriate. This parameter adaptation resolves the contradiction between resource efficiency and communication efficiency.
3Stability of the object's composition
If the UE always transmits HARQ-ACK feedback regardless of overlap, then feedback is reported consistently, but downlink resources are wasted and misunderstandings occur
Solution Approach 1:
The patent segments the HARQ-ACK feedback transmission decision into different cases based on the overlap condition. Instead of a single uniform transmission approach, the system segments the behavior into: transmit normally when no overlap, delay when overlap with downlink symbols, and cancel when overlap with flexible symbols. This segmentation maintains consistency within each segment while optimizing overall resource usage across different scenarios.
Data Source
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AI summary
Aspects of the present disclosure relate to wireless communications, and more particularly, to mechanisms for using block acknowledgments to acknowledge semipersistently scheduled (SPS) occasions from multiple SPS configurations. An example method generally includes determining that a slot scheduled for reporting acknowledgment feedback for an SPS physical downlink shared channel (PDSCH) potentially overlaps with at least one downlink or flexible symbol, deciding whether to cancel or to delay reporting the acknowledgment feedback to a network entity based on one or more conditions, and canceling or delaying reporting the acknowledgment feedback to the network entity, in accordance with the decision.