HARQ Feedback Timing for Multi-PDSCH Grants
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently transmitting hybrid automatic repeat request (HARQ) feedbacks for multiple sub-groups of transmissions scheduled via a single downlink control information (DCI), particularly in low-latency extended reality (XR) applications, where delayed feedback timing can lead to significant delays and affect the packet delay budget (PDB).
Innovation Solution
The proposed solution involves transmitting HARQ feedbacks for different sub-groups of physical downlink shared channel (PDSCH) transmissions scheduled via a same DCI, with the DCI indicating HARQ feedback timing and physical uplink control channel (PUCCH) resources for each sub-group. This allows for timely feedback after decoding within each sub-group, reducing overall latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single DCI schedules multiple transmissions and a single HARQ feedback is provided for all transmissions, then device complexity is reduced, but feedback timing is delayed and latency increases
Solution Approach 1:
The patent segments the multiple transmissions scheduled by a single DCI into different sub-groups, and provides separate HARQ feedback for each sub-group. This segmentation allows the UE to transmit feedback for each sub-group individually rather than waiting for all transmissions to complete, thereby reducing feedback timing delay while maintaining manageable device complexity through structured organization of feedback processes.
2Reliability
If HARQ feedback timing is extended to accommodate all transmissions, then feedback completeness is improved, but latency for individual sub-groups increases
Solution Approach 1:
By dividing transmissions into sub-groups with independent feedback mechanisms, the patent ensures that feedback for each sub-group is transmitted as soon as it is ready, improving overall feedback completeness without requiring extension of feedback timing for all transmissions. Each sub-group's feedback is handled independently, preventing latency propagation across all transmissions.
Solution Approach 2:
The patent implements periodic HARQ feedback transmission for each sub-group according to their respective timing requirements. This periodic action ensures that feedback is provided regularly and promptly for each sub-group, maintaining reliability while minimizing latency by not waiting for all transmissions to complete before sending any feedback.
3Loss of time
If separate HARQ feedback is transmitted for each sub-group, then latency is reduced and feedback timing is improved, but device complexity increases
Solution Approach 1:
The patent structures the feedback mechanism by segmenting transmissions into sub-groups with defined feedback procedures. This segmentation reduces latency by enabling parallel feedback processing while controlling device complexity through systematic organization of feedback resources, timing configurations, and transmission procedures for each sub-group.
Solution Approach 2:
The patent implements a universal feedback framework that handles multiple sub-groups through a common set of procedures and resource allocation mechanisms. This multi-functionality approach allows the system to manage separate feedback for each sub-group using standardized processes, reducing the perceived complexity while achieving lower latency through parallel feedback transmission.
Data Source
AI summary
Certain aspects of the present disclosure provide a method for wireless communications by a user equipment (UE). The UE receives downlink control information (DCI) scheduling multiple transmissions belonging to a plurality of sub-groups. Each sub-group includes one or more transmissions. The DCI indicates at least one feedback timing. The UE receives the multiple transmissions belonging to the plurality of sub-groups. The UE transmits feedback for each sub-group of the one or more transmissions, in accordance with the at least one feedback timing.