Multi-TTI HARQ-ACK Feedback Logic for DCI Blind Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication technologies, when a sub-carrier space is large, scheduling multiple physical downlink shared channels (PDSCHs) across multiple transmission time intervals (TTIs) leads to high overhead for downlink control information (DCI) blind detection, and existing methods fail to ensure that hybrid automatic repeat request acknowledgement (HARQ-ACK) feedback includes acknowledgments for all scheduled PDSCHs in a single HARQ-ACK codebook.
Innovation Solution
A method where a user equipment determines a first slot set corresponding to multi-TTI PDSCHs and a second slot set within a feedback window, identifying target slots that are in both sets and calculating a logical HARQ-ACK for these slots to ensure all PDSCHs' acknowledgments are included in the HARQ-ACK codebook sent on the physical uplink control channel (PUCCH).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one DCI schedules multiple PDSCHs across multiple TTIs to reduce DCI overhead, then the number of DCIs is reduced and complexity of blind detection is reduced, but it becomes difficult to ensure that HARQ-ACK feedback includes acknowledgments for all scheduled PDSCHs in a single HARQ-ACK codebook
Solution Approach 1:
The patent segments the feedback window into multiple groups, with each group corresponding to a specific TTI. This segmentation allows the system to handle multiple PDSCHs scheduled by one DCI by organizing their HARQ-ACK feedback into distinct groups, ensuring that acknowledgments for all PDSCHs across different TTIs are properly included in the HARQ-ACK codebook without increasing DCI overhead
Solution Approach 2:
The patent introduces a group dimension to the HARQ-ACK feedback structure. By organizing feedback into groups corresponding to different TTIs and using group-based indexing, the system can accommodate multi-TTI scheduling while maintaining a single HARQ-ACK codebook. This dimensional organization resolves the conflict between reduced DCI overhead and complete HARQ-ACK feedback
2Reliability
If the feedback window includes slots for all multi-TTI PDSCHs, then all PDSCH acknowledgments can be included, but the feedback window may include slots that do not correspond to any scheduled PDSCH, increasing overhead
Solution Approach 1:
The patent applies local quality by making the feedback window configuration adaptive to the actual scheduling scenario. Instead of using a fixed feedback window that always includes all possible slots, the system configures the feedback window and its groups based on the actual multi-TTI scheduling, including only the necessary slots that correspond to scheduled PDSCHs. This reduces overhead while ensuring completeness of HARQ-ACK feedback
Data Source
AI summary
A method for sending a HARQ-ACK is performed by a user equipment, and includes: determining a first slot set and a second slot set, wherein the first slot set includes slots corresponding to multi-TTI PDSCHs, and the second slot set includes slots in a feedback window corresponding to a HARQ-ACK codebook and the HARQ-ACK codebook is included in a PUCCH for feeding back HARQ-ACKs of the multi-TTI PDSCHs; determining at least one slot group that is in the first slot set and is not in the second slot set and a target slot one-to-one corresponding to each slot group; determining a logical HARQ-ACK on the target slot according to an HARQ-ACK on each slot in each slot group and an HARQ-ACK on the target slot corresponding to each slot group; and sending the HARQ-ACK codebook.