DAI-Based HARQ-ACK Transmission for Non-Numerical K1 Scheduling
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Solution Overview
Problem
In 5G NR-U channels, the non-numerical slot offset (K1) in downlink control information (DCI) for PDSCH scheduling leads to missed HARQ-ACK feedback, causing interference and incorrect resource occupancy by user equipment (UE), as the UE mistakenly uses the wrong PUCCH resource for HARQ-ACK transmission.
Innovation Solution
The method involves determining whether the downlink assignment index (DAI) fields in multiple DCIs meet a predetermined condition to ensure accurate HARQ-ACK information transmission by using a modulo operation to verify the correct DCI for scheduling PUCCH resources, thereby reducing resource occupancy errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If non-numerical slot offset (K1) is used in DCI for PDSCH scheduling, then HARQ-ACK feedback can be delayed to later slots, but UE may mistakenly use wrong PUCCH resource for HARQ-ACK transmission causing interference and resource occupancy errors
Solution Approach 1:
The patent introduces DAI (Downlink Assignment Index) as an intermediary field in DCI to establish a correspondence relationship between PDSCH scheduling DCI and PUCCH resource indication DCI. This intermediary mechanism ensures that even when non-numerical K1 is used for feedback delay, the UE can accurately identify the correct PUCCH resource through the DAI-based mapping relationship, preventing resource occupancy errors and interference.
2Adaptability or versatility
If UE uses DCI with non-numerical K1 value to schedule PDSCH, then flexible HARQ-ACK timing is achieved, but UE cannot determine correct PUCCH resource for feedback transmission
Solution Approach 1:
The patent implements a feedback mechanism where the DAI field in DCI provides feedback information about the correspondence relationship between PDSCH scheduling and PUCCH resource indication. This feedback allows the UE to accurately determine the correct PUCCH resource even when non-numerical K1 is used, maintaining both timing flexibility and operational clarity.
Solution Approach 2:
The DAI field serves as an intermediary that bridges the gap between PDSCH scheduling DCI and PUCCH resource indication. It provides the necessary mapping information enabling the UE to correctly identify the associated PUCCH resource while maintaining the flexibility of non-numerical K1 timing arrangements.
3Productivity
If multiple DCI with different K1 values are transmitted, then HARQ-ACK feedback can be scheduled at different times, but UE may confuse which DCI corresponds to which PUCCH resource
Solution Approach 1:
The DAI field acts as an intermediary identifier that maintains clear correspondence information between multiple DCI and their associated PUCCH resources. By including DAI in both the PDSCH scheduling DCI and the PUCCH resource indication DCI, the patent ensures that UE can accurately track which DCI corresponds to which PUCCH resource, preventing information loss and confusion even when multiple different K1 values are used.
Data Source
AI summary
A method for transmitting hybrid automatic repeat request acknowledgement (HARQ-ACK) information and a communication device are provided. The method includes: receiving first downlink control information (DCI), in which a time domain offset information field of the first DCI has a first value; receiving second DCI, in which a time domain offset information field of the second DCI has a second value different from the first value; and sending HARQ-ACK information of a physical downlink shared channel (PDSCH) transmission scheduled by the first DCI based on the second DCI, in response to determining that a value of a downlink assignment index (DAI) field included in the second DCI and a value of a DAI field included in the first DCI meet a predetermined condition.