HARQ Feedback Postponement for 5G TDD Slot Conflicts

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Solution Overview

Problem

In 5G NR communication systems, conflicts between semi-persistent scheduling (SPS) PDSCH and TDD configuration lead to HARQ feedback discards, causing performance loss due to HARQ feedback falling into non-uplink slots, which are not transmitted.

Innovation Solution

A mechanism is designed to postpone HARQ feedback when conflicts occur, allowing it to be transmitted on available uplink channels after the originally scheduled time, with conditions for postponement based on aggregation factors and uplink channel availability, and using PUCCH or PUSCH resources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If HARQ feedback is transmitted according to fixed k1 timing configuration, then the transmission timing is simple and deterministic, but conflicts with TDD configuration cause HARQ feedback to be discarded when falling into non-uplink slots

Engineering Contradiction:
ImproveHARQ feedback transmission timing simplicityVSAvoidHARQ feedback transmission reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies dynamics by making the HARQ feedback transmission timing flexible rather than fixed. The UE dynamically determines the transmission timing based on whether the originally scheduled slot is available for uplink transmission. When conflict occurs, the UE postpones transmission to the next available uplink slot, transforming the static k1 timing mechanism into a dynamic adaptation mechanism that resolves TDD configuration conflicts.

Inventive Principle:
Principle #15Dynamics

2Ease of manufacture

If HARQ feedback is discarded when conflicting with TDD non-uplink slots, then the system follows current 3GPP protocol simply, but performance loss occurs due to information loss

Engineering Contradiction:
Improveprotocol compliance simplicityVSAvoidHARQ feedback information loss
Core Design Contradiction:
Ease of manufactureVSLoss of information

Solution Approach 1:

The patent converts the harmful effect of TDD configuration conflicts into a beneficial mechanism. Instead of simply discarding conflicting HARQ feedback as per current protocol, the invention transforms these conflicts into triggers for postponement to alternative uplink slots. This converts the harmful collision into a useful adaptive timing adjustment, ensuring feedback transmission while maintaining protocol compliance.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Device complexity

If multiple SPS PDSCH are configured with same k1 value, then the configuration is simplified, but all feedbacks must be transmitted in the same slot causing potential overload and conflicts

Engineering Contradiction:
Improveconfiguration simplicityVSAvoidfeedback transmission efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent applies segmentation by dividing the feedback transmission load across multiple time slots rather than concentrating it in a single slot. When multiple SPS PDSCH are configured, the system segments their feedback transmissions based on slot availability, distributing the burden to avoid overload and improve overall transmission efficiency while maintaining configuration simplicity.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4277184B1HARQ transmission enhancement method, communication device, and readable storage medium
Publication Date: 2025.09.24 JRD COMM (SHENZHEN) LTD
  • EP4277184B1 patent drawingFigure 1~2
  • EP4277184B1 patent drawingFigure 3~4
  • EP4277184B1 patent drawingFigure 5

AI summary

Disclosed in the present application is a HARQ transmission enhancement method, comprising: receiving downlink transmission sent by a base station; when sending of a HARQ feedback signal for the downlink transmission is abnormal, determining whether the HARQ feedback signal satisfies a condition for postponing feedback; and if yes, selecting an uplink channel after an originally scheduled sending time unit of the HARQ feedback signal to transmit at least part of the HARQ feedback signal. Further disclosed in the present application are a communication device and a readable storage medium.