Sidelink Retransmission Feedback for Unused Dynamic Grants
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Solution Overview
Problem
In NR V2X communication, when dynamic grant resources are scheduled but not used for transmission, it leads to resource wastage and inconsistent understanding between the terminal equipment and the network device, causing erroneous scheduling.
Innovation Solution
The terminal equipment transmits indication information via a physical uplink control channel when dynamic grant resources are not used for sidelink retransmission, indicating successful transmission or the need for retransmission, and starts a timer for buffer management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dynamic grant resources are scheduled by the network device, then resource allocation flexibility is improved, but resource wastage occurs when the scheduled resources are not used for transmission
Solution Approach 1:
The terminal equipment feeds back indication information to the network device via PUCCH to indicate whether dynamic grant resources are used for transmission. This feedback mechanism allows the network device to understand the actual usage status of scheduled resources, enabling it to adjust future scheduling decisions and avoid allocating resources that will not be used, thereby reducing resource wastage while maintaining allocation flexibility.
2Reliability
If dynamic grant resources are scheduled for retransmission, then retransmission capability is improved, but inconsistent understanding between terminal equipment and network device occurs leading to erroneous scheduling
Solution Approach 1:
The terminal equipment transmits indication information via PUCCH to explicitly inform the network device whether dynamic grant resources are being used for retransmission. This feedback eliminates inconsistent understanding between the terminal and network device, ensuring that the network device can accurately track the retransmission status and make correct scheduling decisions, thereby maintaining reliable retransmission capability without erroneous scheduling.
3Loss of information
If indication information is transmitted via PUCCH, then resource usage consistency is improved, but additional signaling overhead is introduced
Solution Approach 1:
The PUCCH channel is utilized to serve multiple purposes: it not only carries uplink control information but also conveys indication information about dynamic grant resource usage status. By making the PUCCH multi-functional, the patent achieves resource usage consistency without requiring separate dedicated signaling channels, thereby minimizing additional signaling overhead while ensuring accurate information exchange between terminal and network device.
Data Source
AI summary
A retransmission method and apparatus for sidelink transmission. The method includes: receiving, by a terminal equipment, downlink control information (DCI) of which CRC being scrambled by an SL-CS-RNTI; and when a dynamic grant resource scheduled by the downlink control information is not used to transmit sidelink retransmission, transmitting indication information via a physical uplink control channel indicated by the downlink control information, the indication information indicating success of sidelink transmission or that a network device is not needed to schedule retransmission.