HARQ-ACK Codebook Handling for 5G NTN Feedback
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Solution Overview
Problem
Current 5G New Radio (NR) systems face challenges in HARQ feedback configuration and codebook construction, particularly for Non-Terrestrial Networks (NTN), where Type-2 and Type-1 HARQ-ACK codebooks lack HARQ feedback configurations for SPS PDSCH, and there is uncertainty in handling counter DAI and total DAI counting for HARQ feedback-disabled processes.
Innovation Solution
The method involves determining HARQ feedback configurations for multiple HARQ processes, generating HARQ-ACK codebooks based on these configurations, and transmitting them between terminal and network devices, with specific handling of counter and total DAI fields to enable or disable HARQ feedback, and constructing HARQ feedback bits for processes with feedback enabled or disabled.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If HARQ feedback is disabled for certain HARQ processes to reduce feedback overhead, then signaling complexity is reduced, but the ability to accurately track and manage HARQ-ACK codebook construction is degraded
Solution Approach 1:
The patent extracts and separates the handling of HARQ feedback for enabled and disabled processes. For disabled processes, the counter DAI field is reserved (not used for counting), while for enabled processes, normal DAI counting applies. This separation allows the system to reduce feedback overhead for disabled processes while maintaining accurate codebook construction for enabled processes through distinct handling rules.
Solution Approach 2:
The patent applies different quality characteristics to different parts of the HARQ feedback system. For HARQ processes with feedback disabled, the counter DAI is reserved (different property), while for processes with feedback enabled, the counter DAI functions normally. This local differentiation resolves the contradiction by allowing overhead reduction in specific areas without compromising overall system functionality.
2Loss of information
If counter DAI field is reserved for HARQ processes with feedback disabled, then feedback overhead is reduced, but measurement precision of total DAI counting is degraded
Solution Approach 1:
The patent introduces the total DAI field as an intermediary to compensate for the reserved counter DAI field. When counter DAI is reserved for disabled HARQ processes, the total DAI field provides the necessary counting information to maintain measurement precision. This intermediary mechanism ensures that even when counter DAI is not used, the system can still accurately track the total number of HARQ-ACK bits through the total DAI field.
3Manufacturing precision
If HARQ feedback configurations are provided for all HARQ processes, then codebook construction accuracy is improved, but signaling overhead is increased
Solution Approach 1:
The patent applies partial action by providing HARQ feedback configurations selectively rather than for all processes. For HARQ processes where feedback is disabled, the configuration is minimal (counter DAI reserved). For processes where feedback is enabled, full configurations are provided. This partial approach maintains codebook construction accuracy for enabled processes while reducing overall signaling overhead by not providing unnecessary configurations for disabled processes.
Data Source
AI summary
Embodiments of the present disclosure relate to methods, devices and computer readable storage media for hybrid automatic repeat request acknowledgement. (HARQ-ACK) codebook handling. In example embodiments, a method is provided. The method comprises determining, at a terminal device, respective hybrid automatic repeat request (HARQ) feedback configurations of a plurality of HARQ processes, wherein each HARQ feedback configuration indicates whether HARQ feedback is enabled or disabled for a corresponding HARQ process; and generating a HARQ-ACK codebook for Physical Downlink Shared Channel (PDSCH) based on the HARQ feedback configurations of the plurality of HARQ processes; and transmitting the HARQ-ACK codebook to a network device.