HARQ-ACK Codebook Indexing for Multi-TTI PDSCH Scheduling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication networks, the high blind detection overhead of downlink control information (DCI) and the complexity of hybrid automatic repeat request (HARQ-ACK) feedback are exacerbated by multi-TTI PDSCH scheduling, particularly when multiple PDSCHs are scheduled by a single piece of DCI, leading to increased bits required for index parameters like C-DAI and T-DAI.
Innovation Solution
A method for determining HARQ-ACK codebooks by user equipment (UE) and network devices, where index parameters such as C-DAI and T-DAI are determined based on the number of pieces of DCI, maintaining the original bit occupancy, thus accurately feeding back type-2 HARQ-ACKs without increasing the number of bits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one piece of DCI schedules multiple PDSCHs in multi-TTI design, then the number of DCI pieces is reduced and blind detection complexity is lowered, but the HARQ-ACK codebook size and index parameter bits increase
Solution Approach 1:
The patent segments the HARQ-ACK codebook into multiple groups, where each group corresponds to a specific time slot or scheduling unit. This segmentation allows the UE to manage and feedback HARQ-ACK information in a structured manner, reducing the overall complexity of the codebook while maintaining accurate acknowledgment for multiple PDSCHs scheduled by a single DCI.
Solution Approach 2:
The patent introduces a group index parameter to organize HARQ-ACK information across different time slots or scheduling groups. By adding this dimensional organization, the system can handle multi-TTI scheduling without proportionally increasing the bit occupancy, as the group structure enables compact representation of multiple acknowledgments.
2Measurement precision
If index parameters like C-DAI and T-DAI are increased to accommodate multiple PDSCHs, then HARQ-ACK feedback accuracy is maintained, but the number of bits occupied by index parameters increases
Solution Approach 1:
The patent employs dynamic determination of the number of PDSCHs scheduled by a DCI, where the index parameters adapt based on the actual scheduling scenario. The UE and network device coordinate to determine the codebook size dynamically, allowing accurate HARQ-ACK feedback without requiring a fixed large bit allocation, thus optimizing the balance between precision and bit occupancy.
Solution Approach 2:
The patent changes the parameter organization by introducing group-based indexing and dynamic codebook size determination. Instead of using fixed large index parameters, the system adjusts the codebook structure and index parameters based on the actual number of scheduled PDSCHs and their grouping, maintaining feedback accuracy while reducing bit requirements.
3Adaptability or versatility
If each PDSCH is scheduled with one piece of DCI individually, then scheduling flexibility is ensured, but the blind detection overhead of DCI becomes too high
Solution Approach 1:
The patent merges multiple PDSCH scheduling into a single DCI message, allowing one DCI to schedule multiple PDSCHs across different time slots. This merging reduces the total number of DCI messages that the UE needs to blindly detect, thereby reducing detection overhead while maintaining the ability to schedule multiple data transmissions with different characteristics.
Solution Approach 2:
The DCI message is designed with multi-functionality to handle different scheduling scenarios. A single DCI can schedule multiple PDSCHs with different time slot allocations, and the HARQ-ACK codebook structure adapts to accommodate various numbers of scheduled PDSCHs. This universal design maintains scheduling flexibility while reducing the frequency of DCI transmissions.
Data Source
AI summary
A method for determining a hybrid automatic repeat request acknowledgement (HARQ-ACK) codebook, performed by a user equipment, including: determining an index parameter according to a number of at least one piece of downlink control information (DCI), in response to a network device scheduling the at least one piece of DCI, and each piece of DCI in the at least one piece of DCI scheduling at least one physical downlink shared channel (PDSCH); and determining the HARQ-ACK codebook corresponding to the at least one piece of DCI according to the index parameter.