HARQ-ACK Feedback Mechanism for Repeated Downlink Data in 5G URLLC
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Solution Overview
Problem
Current 5G mobile communication systems lack a mechanism for effectively feeding back information on the decoding result of downlink data repeatedly transmitted in a slot, which is crucial for ensuring ultra-high reliability and low latency in URLLC services.
Innovation Solution
A method and apparatus for sending hybrid automatic repeat request acknowledgement/negative acknowledgement information, where a terminal device or network device determines a downlink data occasion set and feedback location based on a time domain resource set, allowing for semi-persistent codebook feedback to ensure correct decoding result feedback for downlink data repeatedly transmitted in a slot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If downlink data is repeatedly transmitted in a slot to ensure ultra-high reliability, then reliability is improved, but the current protocol lacks a feedback mechanism which causes loss of information about decoding results
Solution Approach 1:
The patent introduces a feedback mechanism by determining downlink data occasion sets and corresponding feedback location sets based on time domain resource sets. Each downlink data occasion is mapped to specific feedback locations where ACK/NACK information is transmitted, enabling the terminal to feed back decoding results for repeatedly transmitted downlink data.
Solution Approach 2:
The patent segments the time domain resources into multiple downlink data occasions and corresponds them to multiple feedback locations. This segmentation allows independent feedback for each repeated transmission, enabling precise tracking of decoding results across multiple transmission attempts within a slot.
2Reliability
If downlink data is repeatedly transmitted K times in a time unit to improve reliability, then reliability is improved, but the complexity of determining feedback locations and codebooks increases
Solution Approach 1:
The patent performs preliminary determination of downlink data occasion sets and feedback location sets based on the time domain resource set before actual feedback transmission. This pre-establishment of mapping relationships simplifies the feedback process during execution, as the terminal only needs to follow pre-defined mappings rather than calculating feedback locations in real-time.
Solution Approach 2:
The patent creates a universal mapping mechanism where any time domain resource set can be converted into corresponding downlink data occasion sets and feedback location sets using the same determination rules. This multi-functional approach allows the system to handle various repetition configurations (K≥2) with a single unified mechanism, reducing overall system complexity.
3Productivity
If semi-persistent codebook feedback is implemented for downlink data occasions, then feedback efficiency is improved, but the requirement for precise time domain resource configuration increases
Solution Approach 1:
The patent utilizes parameter changes in time domain resource configuration, specifically using the start symbol and length of time domain resources to determine downlink data occasions. By changing these parameters dynamically, the system can adapt to different transmission scenarios while maintaining consistent feedback location determination, making the configuration process more flexible and easier to implement.
Data Source
AI summary
A method and an apparatus for sending hybrid automatic repeat request acknowledgement/negative acknowledgement information are disclosed, and relate to the communications field, to specify a mechanism for feeding back information indicating whether a decoding result of downlink data repeatedly transmitted in a slot is correct. The method includes: determining a first downlink data occasion set based on a time domain resource indicated by a time domain resource allocation (TDRA) table; determining a first downlink data occasion based on a start time domain resource for sending downlink data; adding feedback information (for example, information indicating whether a decoding result of the downlink data is correct) to a feedback location corresponding to the first downlink data occasion; determining a feedback slot based on a slot to which the start time domain resource for sending the downlink data belongs and a first offset K1; and feeding back a HARQ-ACK codebook in the feedback slot.