Downlink Feedback Indication Processing for Slot Aggregation Ambiguity
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Solution Overview
Problem
There is ambiguity in determining the effective ACK/NACK feedback for HARQ processes in slot aggregation scenarios, where the minimum processing window covers different parts of aggregated slots, leading to unclear interpretation of downlink feedback indications in 5G NR-U networks.
Innovation Solution
A method for user equipment to determine effective ACK/NACK feedback by considering the minimum processing duration and relative time position of sub-packets with respect to the downlink feedback indication signal, allowing for valid or invalid ACK/NACK indications to be determined based on predetermined conditions, thereby clarifying the interpretation of feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If time slot aggregation is used to enhance transmission reliability, then transmission reliability is improved, but ambiguity arises in determining effective ACK/NACK feedback
Solution Approach 1:
The patent applies parameter changes by modifying the interpretation rules of ACK/NACK feedback based on the temporal relationship between DFI reception and slot aggregation transmission. Specifically, it changes the effectiveness determination parameter from a fixed rule to a dynamic one that considers whether the DFI is received within the minimum processing duration D after the last symbol of the aggregated slots, thereby resolving the feedback interpretation ambiguity while maintaining transmission reliability
Solution Approach 2:
The patent applies local quality by creating different feedback interpretation rules for different time intervals. For ACK/NACK feedback corresponding to slot aggregation, it distinguishes between DFIs received within the minimum processing duration D (effective feedback) and those received after D (ineffective feedback). This localized differentiation in feedback validity based on timing resolves the ambiguity without affecting the overall reliability mechanism
2Loss of information
If minimum processing duration D is enforced for ACK/NACK effectiveness, then feedback interpretation clarity is improved, but processing time constraints are imposed
Solution Approach 1:
The patent applies preliminary action by pre-defining the minimum processing duration D and the conditions under which ACK/NACK feedback is considered effective. This preliminary establishment of timing rules allows the system to automatically determine feedback validity without requiring additional processing or negotiation, thus achieving clarity while minimizing time loss
Solution Approach 2:
The patent applies dynamics by making the feedback effectiveness determination dynamic rather than static. The same ACK/NACK feedback can be effective or ineffective depending on when the DFI is received relative to the minimum processing duration D. This dynamic approach provides clear interpretation rules that adapt to different timing scenarios without imposing rigid time constraints on the transmission itself
Data Source
AI summary
A method for downlink feedback indication processing perfumed by a user equipment includes: receiving (210) from a base station a downlink feedback indication (DFI) signal, where the DFI signal comprises an ACK/NACK indication associated with a first HARQ process defined for a transmission to the base station of an uplink data packet using time slot aggregation. A user equipment is also provided.