HARQ Feedback Optimization in NR V2X Groupcast
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Solution Overview
Problem
In V2X sidelink communication, existing HARQ feedback mechanisms cannot determine whether a receiving UE is within or out of communication range, leading to unnecessary retransmissions, increased transmission collision probability, and wasted transmit power.
Innovation Solution
A method where location information and communication range are transmitted to UEs, allowing them to determine their relative location and only provide HARQ feedback within the communication range, thereby avoiding unnecessary retransmissions and improving spectrum efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ feedback mechanism is implemented without location information, then feedback can be provided for all received transmissions, but unnecessary retransmissions occur to UEs out of communication range
Solution Approach 1:
The transmitting UE sends location information and communication range requirements to receiving UEs before HARQ feedback is provided. This preliminary action allows receiving UEs to determine whether they are within the communication range and only provide feedback if appropriate, avoiding unnecessary retransmissions and power waste
2Reliability
If HARQ feedback is provided for all transmissions, then all decoding failures are detected, but transmission collision probability increases
Solution Approach 1:
The patent applies different feedback behaviors based on the local condition of whether the receiving UE is within the communication range. UEs within range provide full HARQ feedback for all TBs, while UEs outside range provide reduced feedback only for certain TBs, optimizing the balance between detection reliability and collision probability
3Productivity
If location information is transmitted to UEs, then unnecessary retransmissions are avoided, but signaling overhead increases
Solution Approach 1:
The location information and communication range parameters are designed to serve multiple functions: they enable HARQ feedback optimization, support transmission collision avoidance, and provide basis for productivity improvement. This multi-functionality justifies the signaling overhead by delivering multiple benefits from a single information exchange
Data Source
AI summary
Embodiments of the present disclosure relate to method and apparatus for HARQ feedback. According to an embodiment of the present disclosure, a method can include: transmitting, to a first user equipment (UE), location information of a second UE and a communication range required for at least one sidelink transmission from the second UE, wherein each of the at least one sidelink transmission comprises a set of transport blocks (TBs); detecting feedback information associated with a corresponding TB of the set of TBs from the first UE on a set of feedback resources; and determining whether to retransmit the corresponding TB of the set of TBs based on the detection result of the feedback information. Embodiments of the present disclosure can avoid unnecessary retransmission and can improve transmission efficiency in NR V2X groupcast communication.