HARQ-ACK Positioning for SPS Release in Multi-PDSCH NR Slots

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Solution Overview

Problem

In the 5G NR system, there is no clear method for Hybrid Automatic Repeat Request-Acknowledgement (HARQ-ACK) feedback on Physical Downlink Control Channel (PDCCH) indicating Semi-Persistent Scheduling (SPS) resource release for terminals supporting multiple unicast PDSCH receptions in one slot, leading to ambiguous HARQ-ACK feedback modes when multiple SPS configurations are present.

Innovation Solution

A method for mapping HARQ-ACK feedback of PDCCH indicating SPS resource release to a feedback position determined by a reference time domain resource within a HARQ-ACK feedback sequence, ensuring clear feedback even when multiple SPS configurations are supported.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If R-15 mechanism is used for HARQ-ACK feedback on PDCCH indicating SPS resource release, then HARQ-ACK feedback can be performed when only one unicast PDSCH reception capability is supported, but PDCCH indicating SPS resource release cannot be transmitted in the same slot as PDSCH, resulting in failure to issue release PDCCH

Engineering Contradiction:
ImproveHARQ-ACK feedback reliabilityVSAvoidSPS resource release efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies dynamics by making the PDCCH transmission flexible - it can be transmitted in the same slot as PDSCH when the terminal supports multiple unicast PDSCH receptions, but follows R-15 constraints when only single reception is supported. This dynamic adaptation resolves the contradiction between reliability and productivity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of unicast PDSCH reception capability (from a=1 to a>1) to enable different HARQ-ACK feedback mechanisms. When a>1, the system allows same-slot PDCCH and PDSCH transmission with appropriate HARQ-ACK feedback positioning, resolving the contradiction.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If multiple SPS configurations are supported on one carrier, then service flexibility is improved, but the number of downlink transmissions in a slot increases, exceeding terminal reception capability and HARQ-ACK feedback positions

Engineering Contradiction:
ImproveSPS configuration flexibilityVSAvoidHARQ-ACK feedback position management
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the HARQ-ACK feedback positions into different types: those corresponding to PDSCH transmissions and those corresponding to PDCCH indicating SPS resource release. This segmentation allows independent management and positioning of different feedback types, reducing complexity while supporting multiple SPS configurations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a reference time domain resource as an intermediary to determine the positioning of HARQ-ACK feedback for PDCCH indicating SPS resource release. This intermediary provides a systematic method for positioning feedback in complex multi-SPS scenarios, managing the increased complexity through a structured approach.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If HARQ-ACK feedback position is reserved only for PDSCH transmission opportunities, then feedback position management is simplified, but there is no position for HARQ-ACK feedback on PDCCH indicating SPS resource release

Engineering Contradiction:
ImproveHARQ-ACK feedback position managementVSAvoidHARQ-ACK feedback information
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The patent makes the HARQ-ACK feedback mechanism universal by creating feedback positions that can serve both PDSCH transmissions and PDCCH indicating SPS resource release. The same HARQ-ACK feedback mechanism handles both types of transmissions, preventing information loss while managing complexity through a unified approach.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4135448B1HARQ-ACK feedback method and apparatus, terminal and base station
Publication Date: 2026.01.07 DATANG MOBILE COMM EQUIP CO LTD
  • EP4135448B1 patent drawingFigure 1~2
  • EP4135448B1 patent drawingFigure 3~4
  • EP4135448B1 patent drawingFigure 5~7

AI summary

A HARQ-ACK feedback method and device, a terminal, and a base station are provided. The method applied to the terminal includes: if a PDCCH indicating an SPS resource release is received in a slot for receiving an SPS PDSCH transmission, mapping a HARQ-ACK feedback of the PDCCH indicating the SPS resource release, to a feedback position determined according to a reference time domain resource in a HARQ-ACK feedback sequence; transmitting the HARQ-ACK feedback sequence including the HARQ-ACK feedback of the PDCCH indicating the SPS resource release.