Dynamic HARQ Feedback Timing in NR-U Channel Groups
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Solution Overview
Problem
In the New Radio (NR) system, especially in the NR-U system, the current HARQ feedback method leads to discontinuous downlink resources due to frequent feedback transmissions, reducing system efficiency, and poses challenges when HARQ feedback timing values are mixed, with some being valid and others invalid within the same PDSCH group.
Innovation Solution
A method where a terminal device receives first and second DCI, both belonging to the same channel group, with different time information fields, allowing the terminal device to determine feedback transmission time based on the second DCI, enabling flexible feedback and reducing unnecessary transmissions by updating the feedback time indicated in the first DCI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ feedback is performed frequently based on PDSCH group, then feedback reliability is improved, but downlink resource continuity deteriorates due to discontinuous resources
Solution Approach 1:
The patent implements dynamic feedback timing by allowing the time information field in subsequent DCI to update and override the feedback time indicated in previous DCI. This dynamic mechanism enables the system to adapt feedback transmission timing to available downlink resources, ensuring resource continuity while maintaining feedback reliability. The feedback time is no longer fixed but can be dynamically adjusted based on current resource availability.
2Adaptability or versatility
If multiple DCI with different time information fields are transmitted, then feedback flexibility is improved, but device complexity increases
Solution Approach 1:
The patent employs dynamic time information updating where the terminal device processes multiple DCI messages with different time information fields. The latest received time information overrides previous indications, providing feedback flexibility without requiring complex coordination. This dynamic override mechanism simplifies the processing logic compared to managing multiple independent timing schedules.
Solution Approach 2:
Instead of having the terminal device calculate and determine feedback timing based on multiple DCI messages, the network device directly indicates the feedback time in each DCI's time information field. The terminal device simply follows the latest indication, inverting the complexity from the terminal side to the network side, which better controls the overall system complexity.
3Stability of the object's composition
If feedback transmission time is determined by first DCI, then feedback timing is stable, but system efficiency decreases due to unnecessary feedback transmissions
Solution Approach 1:
The patent implements dynamic feedback timing adjustment where the time information field in subsequent DCI can update and override the feedback time originally indicated in the first DCI. This dynamic mechanism prevents unnecessary feedback transmissions by allowing the network to adjust timing based on current resource availability, thereby improving system efficiency while maintaining stable timing through structured updates.
Solution Approach 2:
The patent extracts the feedback timing determination from the first DCI alone and allows subsequent DCI to override it. This separation enables the system to take out the initial timing indication and replace it with updated timing information when resources become available, eliminating unnecessary feedback transmissions and improving overall system efficiency.
Data Source
AI summary
Provided are a method for information feedback, a terminal device and a network device. The method comprises: a terminal device receives first DCI; the terminal device receives second DCI after the first DCL, the downlink channel corresponding to the first DCI and the downlink channel corresponding to the second DCI belonging to the same channel group, the first DCI and the second DCI comprising a time information field, the time information field indicating the time for sending feedback information of the channel group, and the time indicated by the time information field in the first DCI and the time information field in the second DCI being different; and, on the basis of the second DCI, the terminal device determines time information for sending feedback information of the channel group.