One-Shot HARQ-ACK Feedback for Dropped NR Acknowledgments

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing wireless communication systems face inefficiencies in HARQ-ACK feedback, particularly in 5G NR, leading to latency and PDCCH blocking due to dropped HARQ-ACK feedback, which can be addressed by dynamic triggering of one-shot Type-3 HARQ-ACK feedback, but this approach introduces additional latency and resource conflicts.

Innovation Solution

Implementing a UE-triggered, event-based one-shot HARQ-ACK feedback mechanism that autonomously combines and transmits a threshold amount of dropped HARQ-ACK feedback without explicit DCI, reducing latency and improving efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dynamic triggering of one-shot Type-3 HARQ-ACK feedback is implemented, then HARQ-ACK feedback reliability is improved, but latency increases

Engineering Contradiction:

ImproveHARQ-ACK feedback reliabilityVSAvoidfeedback latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The UE autonomously triggers Type-3 HARQ-ACK feedback when the number of dropped HARQ-ACK feedback reaches a threshold, without waiting for DCI triggering from the base station. This preliminary action by the UE eliminates the waiting time for DCI scheduling and reduces overall feedback latency while maintaining reliability through autonomous retransmission triggering

Inventive Principle:

Principle #10Preliminary action

2Reliability

If DCI is used to trigger Type-3 HARQ-ACK feedback for retransmission of dropped SPS HARQ-ACK, then feedback reliability is improved, but PDCCH blocking occurs and latency increases

Engineering Contradiction:

ImproveHARQ-ACK feedback reliabilityVSAvoidPDCCH resource efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The UE autonomously determines when to trigger Type-3 HARQ-ACK feedback based on the number of dropped feedback instances, serving itself without requiring base station intervention via DCI. This self-service mechanism eliminates PDCCH blocking issues and improves resource efficiency while maintaining feedback reliability

Inventive Principle:

Principle #25Self-service

3Loss of time

If UE autonomously triggers one-shot HARQ-ACK feedback, then latency is reduced, but device complexity increases

Engineering Contradiction:

Improvefeedback latencyVSAvoidUE control logic complexity

Core Design Contradiction:

Loss of timeVSDevice complexity

Solution Approach 1:

The autonomous triggering mechanism is segmented into simple, discrete steps: counting dropped HARQ-ACK feedback instances, comparing against a threshold, and triggering feedback when threshold is reached. This segmentation keeps the UE control logic simple and manageable while achieving low latency through autonomous operation

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP4315682B1UE triggered one-shot HARQ-ACK feedback

Publication Date: 2025.12.03 QUALCOMM INC

Figure 1
Figure 2A~2D
Figure 3

AI summary

A method, a computer-readable medium, and an apparatus are provided for wireless communication at a user equipment (UE). The apparatus drops transmission of hybrid automatic repeat request-acknowledgment (HARQ-ACK) feedback for one or more downlink HARQ processes. The apparatus transmits, to a base station, a combined HARQ-ACK feedback triggered by the UE dropping a threshold amount of HARQ-ACK feedback, the combined HARQ-ACK feedback including dropped HARQ-ACK feedback for the one or more downlink HARQ processes.