User Terminal HARQ-ACK Grouping for Multi-Process Feedback

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Solution Overview

Problem

In existing wireless communication systems, the method for determining HARQ-ACK feedback for multiple HARQ processes is unclear, leading to potential deterioration in system performance.

Innovation Solution

The proposed solution involves determining specific HARQ processes and component carriers for HARQ-ACK feedback through DCI, MAC CE, or RRC layer signaling, allowing for flexible and efficient HARQ-ACK reporting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If HARQ-ACK feedback is performed for multiple HARQ processes simultaneously, then system performance is improved through efficient retransmission control, but the complexity of determining which HARQ processes to report increases

Engineering Contradiction:
ImproveHARQ-ACK feedback efficiencyVSAvoidHARQ process determination complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the HARQ-ACK feedback process by dividing multiple HARQ processes into separate groups, where each group is associated with a specific downlink cell. The UE reports HARQ-ACK information for each group separately using different uplink resources, thereby managing the complexity of handling multiple HARQ processes through structured segmentation rather than simultaneous undifferentiated reporting.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension for organizing HARQ-ACK feedback by associating each HARQ process group with a specific downlink cell index. This dimensional organization allows the system to handle multiple HARQ processes across different cells in an ordered manner, transforming the complex multi-dimensional problem into a manageable sequence of cell-specific feedback reports.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Quantity of substance

If all HARQ processes are reported together in a single feedback, then overhead is reduced, but the precision of individual HARQ process acknowledgment decreases

Engineering Contradiction:
ImproveFeedback overheadVSAvoidHARQ process acknowledgment precision
Core Design Contradiction:
Quantity of substanceVSMeasurement precision

Solution Approach 1:

The patent segments HARQ-ACK feedback into cell-specific groups, where each group contains acknowledgments for HARQ processes associated with a particular downlink cell. This segmentation allows the system to maintain separate tracking of individual HARQ processes while organizing feedback efficiently, balancing the need for precision in individual acknowledgments with the goal of reducing overall feedback overhead through structured grouping.

Inventive Principle:
Principle #1Segmentation

3Reliability

If HARQ-ACK feedback timing is extended to accommodate multiple HARQ processes, then completeness of feedback is improved, but the time delay for retransmission control increases

Engineering Contradiction:
ImproveFeedback completenessVSAvoidRetransmission delay
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by having the network pre-configure multiple uplink resources for HARQ-ACK feedback before actual data transmission occurs. These pre-configured resources include different uplink cells and timing relationships that are established in advance through RRC signaling. When HARQ-ACK feedback is needed, the UE can immediately use the pre-assigned resources without waiting for additional configuration, thereby maintaining feedback completeness while minimizing delays.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3941111B1User terminal and wireless communication method
Publication Date: 2026.04.15 NTT DOCOMO INC
  • EP3941111B1 patent drawingFigure 1
  • EP3941111B1 patent drawingFigure 2
  • EP3941111B1 patent drawingFigure 3

AI summary

A user terminal includes a receiving section that receives indication information related to a hybrid automatic repeat request (HARQ)-acknowledgement (ACK) and a control section that reports an HARQ-ACK corresponding to a plurality of HARQ processes based on the indication information on one uplink channel. According to an aspect of the present disclosure, an HARQ-ACK feedback for a plurality of HARQ processes can be appropriately transmitted.