Sidelink HARQ-ACK Control for Terminal Feedback Switching
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Solution Overview
Problem
The operation of terminals when transmitting Hybrid Automatic Repeat Request (HARQ) feedback to a base station in sidelink communication is unclear, particularly in the context of enabling or disabling this feedback function, which is necessary for clarifying the HARQ-Acknowledgement (HARQ-ACK) operation in sidelink communication systems.
Innovation Solution
A terminal is equipped with a receiving unit to receive specific sidelink control information indicating the enable/disable function of HARQ feedback and a control unit to perform the corresponding operation, utilizing Type I and Type II HARQ-ACK codebooks to manage HARQ-ACK transmission to the base station based on Downlink Control Information (DCI) and upper layer signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ feedback function is enabled for sidelink communication, then communication reliability is improved, but terminal operation complexity increases due to unclear feedback transmission procedures
Solution Approach 1:
The patent applies parameter changes by dynamically switching between different HARQ feedback transmission modes based on received indications. The terminal changes the parameter of feedback transmission behavior from one state (transmitting SL HARQ-ACK) to another state (not transmitting SL HARQ-ACK) according to the indication received in sidelink control information or downlink control information, thereby adapting to different communication scenarios while maintaining clear operational procedures.
2Loss of information
If HARQ feedback transmission is always performed, then feedback completeness is improved, but unnecessary feedback transmission increases signaling overhead
Solution Approach 1:
The patent implements dynamics by making the HARQ feedback transmission behavior adjustable and context-dependent. Instead of a static always-transmit approach, the terminal dynamically determines whether to transmit SL HARQ-ACK based on received indications that reflect current communication conditions, such as whether the scheduled terminal is configured to perform HARQ feedback. This dynamic adaptation reduces unnecessary feedback transmissions while ensuring feedback is provided when needed.
3Measurement precision
If the terminal transmits SL HARQ-ACK based on received indication, then feedback accuracy is improved, but detection errors may occur due to ambiguous indication interpretation
Solution Approach 1:
The patent uses an intermediary mechanism by introducing clearly defined indication fields in control information (sidelink control information or downlink control information) that explicitly convey the base station's intent regarding SL HARQ-ACK transmission. This intermediary indication serves as a precise mediator between the base station's scheduling decision and the terminal's feedback transmission behavior, eliminating ambiguous interpretation and reducing detection errors.
Data Source
AI summary
A terminal includes: a receiving unit that receives specific sidelink control information related to an indication that disables a function of performing Hybrid Automatic Repeat Request (HARQ) feedback corresponding to a sidelink to a base station; and a control unit that performs a specific operation for the HARQ feedback in a case where the receiving unit receives the specific sidelink control information related to the indication.