DAI Grouping for Missed PDCCH Detection in HARQ-ACK
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Solution Overview
Problem
Wireless communication systems face inefficiencies in signal transmission and uplink signal control, particularly in recognizing missed PDCCHs, leading to errors in ACK/NACK generation.
Innovation Solution
The method involves using a Downlink Assignment Index (DAI) and DAI group indication information to configure and transmit HARQ-ACK payloads, where the DAI indicates scheduling order values and the DAI group information determines whether the PDCCH corresponds to the last group, allowing for efficient ACK/NACK responses, even if the last PDCCH is missed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional HARQ-ACK transmission methods are used, then the system can maintain simple control procedures, but the system cannot accurately recognize missed PDCCHs leading to ACK/NACK generation errors
Solution Approach 1:
The patent segments the DAI values into multiple groups (DAI group 0, DAI group 1, etc.) where each group contains a specific range of DAI values. This segmentation allows the system to efficiently indicate which group contains the last PDCCH, enabling accurate recognition of missed PDCCHs while maintaining manageable control signaling complexity through structured organization.
Solution Approach 2:
The patent introduces a new dimension by adding group indication information to the existing DAI mechanism. Instead of only using sequential DAI values, the system now uses a two-dimensional approach: DAI group indication (which group) and DAI value within group (position in group). This dimensional enhancement enables more efficient PDCCH tracking and missed PDCCH detection.
2Measurement precision
If the system uses detailed DAI tracking for every PDCCH, then it can improve PDCCH recognition accuracy, but the signaling overhead and processing complexity increase
Solution Approach 1:
The patent applies partial action by only transmitting group indication information for the last PDCCH group rather than providing detailed tracking information for every single PDCCH. This partial information approach is sufficient for the UE to identify missed PDCCHs and generate correct ACK/NACK responses, significantly reducing control signaling overhead while maintaining adequate measurement precision.
Solution Approach 2:
The system performs preliminary organization of PDCCHs into groups with sequential DAI values before transmission. This preliminary structuring allows the UE to efficiently process and track PDCCHs by group rather than individually, reducing the computational complexity and signaling overhead required for precise PDCCH recognition.
3Reliability
If the system implements comprehensive PDCCH monitoring and acknowledgment, then it can reduce transmission errors, but the processing time and complexity increase
Solution Approach 1:
By segmenting PDCCH monitoring into groups with clear boundaries indicated by group indication information, the UE can efficiently process each group separately rather than analyzing every PDCCH individually. This segmentation reduces processing time while maintaining comprehensive monitoring coverage, as the UE only needs to identify the last group to detect any missed PDCCHs within the bundling window.
Solution Approach 2:
The group indication information serves as a feedback mechanism that provides the UE with essential information about the last transmitted PDCCH group. This feedback enables the UE to quickly determine whether any PDCCHs were missed and generate appropriate ACK/NACK responses, reducing processing time while ensuring transmission reliability through accurate error detection.
Data Source
AI summary
The present invention relates to a method and an apparatus for transmitting a signal in a wireless communication system. A physical downlink control channel (PDCCH) is received that has a downlink assignment index (DAI) and DAI group indication information within a subframe (SF) #n-k. A hybrid automatic repeat request acknowledgement (HARQ-ACK) payload is configured by using the DAI and the DAI group indication information. The HARQ-ACK payload is transmitted from an SF #n. A value of the DAI includes a scheduling order value in a cell/SF unit associated with the PDCCH in the SF #n−k. The scheduling order value in a cell/SF unit is counted in a cell-priority manner in a cell/SF domain. The DAI group indication information includes whether the PDCCH is related to a last DAI group, and one DAI group consists of a plurality of consecutive DAI values.