HARQ Feedback Resource Mapping for TDD MTC Systems
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Solution Overview
Problem
The existing HARQ feedback mode in TDD MTC systems is inefficient as it often results in situations where a certain HARQ result is not correctly identified due to the limitation of using a single PUCCH resource for multiple PDSCHs, leading to issues like DTX state occurrence and incomplete feedback.
Innovation Solution
A method and apparatus for determining target HARQ results corresponding to scheduled PDSCHs, which involves selecting a target PUCCH resource to carry a combined HARQ result, allowing for the identification and feedback of multiple HARQ results through a single sub-frame, optimizing the HARQ feedback process by selecting appropriate PUCCH resources based on preset mapping relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single PUCCH resource is used to carry HARQ feedback for multiple PDSCHs scheduled by one PDCCH, then the feedback overhead is reduced, but the ability to accurately identify individual HARQ results deteriorates
Solution Approach 1:
The patent segments the feedback mechanism by separating the PUCCH resource selection from the HARQ result combination. Each PDSCH's HARQ result is individually identified through its associated PUCCH resource index, while the actual feedback content is combined. This segmentation allows multiple PDSCHs to be efficiently feedbacked without losing individual result identification capability.
Solution Approach 2:
The patent introduces an intermediary mechanism where the PUCCH resource index acts as a mediator between the multiple PDSCHs and the feedback system. By using the resource index to identify which PDSCH a HARQ result corresponds to, the system can accurately map feedback results back to their source PDSCHs even when multiple are aggregated in a single feedback transmission.
2Productivity
If multiple PDSCHs are scheduled by one PDCCH, then the scheduling efficiency is improved, but the occurrence of DTX state and incomplete feedback increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring the mapping relationship between PUCCH resources and PDSCHs before feedback transmission. The MTC device determines the PUCCH resource index for each PDSCH in advance, and this pre-established mapping ensures that when feedback is aggregated and transmitted, each HARQ result can be reliably traced back to its corresponding PDSCH, preventing DTX states and incomplete feedback.
Solution Approach 2:
The patent implements a refined feedback mechanism where the PUCCH resource index itself carries identification information about which PDSCH the feedback corresponds to. This feedback structure ensures that even when multiple HARQ results are combined in one transmission, the base station can correctly associate each result with its source PDSCH, maintaining feedback completeness while supporting efficient multi-PDSCH scheduling.
3Adaptability or versatility
If PUCCH format 1b with channel selection is used for HARQ feedback, then the feedback capability is enhanced, but the complexity of resource selection increases when multiple PDSCHs are scheduled by one PDCCH
Solution Approach 1:
The patent extracts the resource selection complexity from the feedback transmission process itself. By separating the PUCCH resource index determination (which identifies the PDSCH) from the HARQ result combination (which provides the feedback content), the system simplifies the overall process. The MTC device only needs to follow predetermined rules to select the resource index, reducing the complexity while maintaining the enhanced feedback capability of format 1b with channel selection.
Data Source
AI summary
A method and apparatus for hybrid automatic repeat request (HARQ) feedback is provided. The method includes: determining at least one target HARQ result corresponding to at least one target PDSCH, wherein the at least one target PDSCH is from all PDSCHs scheduled by a current PDCCH, HARQ results corresponding to the at least one target PDSCH are to be fed back through a current sub-frame; determining a target PUCCH and a combined HARQ result in at least one candidate PUCCH according to the at least one target HARQ result, wherein corresponding target PUCCH resource of the target PUCCH is configured to carry the combined HARQ result, and the combined HARQ result and the target PUCCH resource are configured to identify the at least one target HARQ result; and carrying the combined HARQ result through the target PUCCH resource, and sending the target PUCCH to a base station.