Dynamic HARQ-ACK Codebook Determination via Last DL Assignment Indicator
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Solution Overview
Problem
In wireless communication technology, determining a dynamic HARQ-ACK codebook for multiple downlink or uplink resources across multiple carriers and slots is challenging, especially in scenarios with dynamic downlink associations, leading to potential misunderstandings between base units and remote units regarding the codebook size during data transmission.
Innovation Solution
The introduction of a Last DL Assignment indicator (LDAI) and Last Slot indicator (LSI) in the control information of data transmission helps remote units identify whether a DL transmission is the last in a series, allowing them to synchronize with the base unit on the dynamic HARQ-ACK codebook size, thereby reducing signaling overhead and avoiding misunderstandings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a dynamic HARQ-ACK codebook is used for multiple DL or UL resources across multiple carriers and slots, then the adaptability of the system to dynamic downlink associations is improved, but the difficulty of determining the codebook size increases leading to misunderstandings between base unit and remote unit
Solution Approach 1:
The patent implements a feedback mechanism where the base unit sends downlink assignment indicators (DAI) in each downlink assignment, and the remote unit uses these indicators to determine the codebook size. The DAI provides feedback information about the total number of downlink assignments, enabling the remote unit to accurately determine the HARQ-ACK codebook size without ambiguity, thus resolving the contradiction between adaptability and determination difficulty.
2Ease of operation
If the HARQ-ACK codebook size is preconfigured, then the ease of operation is improved, but the reliability of feedback accuracy deteriorates in dynamic transmission scenarios
Solution Approach 1:
The patent transitions from a static preconfigured codebook size to a dynamic determination mechanism. The HARQ-ACK codebook size is no longer fixed but is dynamically determined by the remote unit based on the downlink assignment indicators received from the base unit. This dynamic approach ensures that the codebook size accurately reflects the actual number of downlink transmissions, thereby maintaining feedback accuracy in dynamic transmission scenarios while preserving ease of operation through automated determination.
3Productivity
If multiple DL transmissions are aggregated across carriers and slots, then the productivity of data transmission is improved, but the loss of information increases due to potential misunderstandings about codebook size
Solution Approach 1:
The patent introduces downlink assignment indicators (DAI) as an intermediary information element that mediates between the base unit's downlink transmissions and the remote unit's HARQ-ACK feedback. The DAI carries information about the total number of downlink assignments, serving as a mediator that ensures both units have consistent understanding of the codebook size. This intermediary mechanism prevents information loss and misunderstandings while enabling efficient aggregation of multiple DL transmissions across carriers and slots.
Data Source
AI summary
The present disclosure is related to a method and apparatus for determining a dynamic hybrid automatic repeat request-acknowledge (HARQ-ACK) codebook. A method for determining a dynamic HARQ-ACK codebook for includes receiving a plurality of downlink (DL) transmissions, wherein each DL transmission has an associated first signal indicating whether the DL transmission is a last transmission of the plurality of DL transmissions. The method further includes transmitting a HARQ-ACK codebook corresponding to the plurality of DL transmissions, wherein, based on the first signal, HARQ-ACK feedback for the last transmission of the plurality of DL transmissions is arranged at the end of the HARQ-ACK codebook. The present disclosure reduces signaling overhead for a dynamic HARQ-ACK codebook and avoids misunderstanding between a base unit and a remote unit when determining the dynamic HARQ-ACK codebook.