HARQ Timer Control for Low-Latency NR-U Grant Retransmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In interference-controlled New Radio Unlicensed (NRU) scenarios, there is a need to reduce the latency of resource transmission, particularly for deprioritized resources, due to conflicts and LBT failures.
Innovation Solution
The method involves determining the state of Hybrid Automatic Repeat Request (HARQ) processes and timers based on satisfied conditions, such as deprioritized MAC PDUs, and adjusting the start time of Configured Grant (CG) and CG-Retransmission Timers to facilitate automatic retransmission of deprioritized resources, thereby reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the CG timer is started at the beginning of the first symbol of PUSCH transmission, then the timer management is simplified, but the transmission latency increases because subsequent CG resources cannot be used for automatic retransmission of deprioritized resources
Solution Approach 1:
The patent segments the timer management into two distinct timers: CG timer for normal operation and CG-Retransmission Timer for retransmission scenarios. This segmentation allows independent control of timer behavior based on transmission priority, resolving the conflict between simplified management and low latency requirements.
Solution Approach 2:
The patent introduces dynamic timer starting behavior where the CG-Retransmission Timer start time adapts based on transmission conditions. For deprioritized resources, the timer starts at the end of the last symbol rather than the beginning, dynamically adjusting to minimize latency while maintaining proper resource management.
2Reliability
If the CG-Retransmission Timer is configured to start at the beginning of the first symbol, then timer synchronization is improved, but automatic retransmission of deprioritized resources is blocked causing increased latency
Solution Approach 1:
The patent applies different timer starting rules to different resource types: prioritized resources use the traditional beginning-of-symbol start time for synchronization, while deprioritized resources use end-of-last-symbol start time to enable immediate retransmission. This local differentiation resolves the contradiction between synchronization and latency.
Solution Approach 2:
The patent prepares the CG-Retransmission Timer in advance with conditional starting logic. When deprioritized resources are detected, the timer is configured to start at the end of the last symbol, preliminarily establishing the timing for immediate retransmission without waiting for traditional synchronization points.
3Ease of operation
If traditional CG timer management is used, then system operation is straightforward, but deprioritized resources cannot be automatically retransmitted leading to increased transmission latency
Solution Approach 1:
The patent enables the system to automatically distinguish between prioritized and deprioritized resources and apply appropriate timer management without external intervention. The terminal device autonomously determines the start time of the CG-Retransmission Timer based on resource priority, achieving self-service operation that maintains simplicity while reducing latency.
Solution Approach 2:
The patent changes the timing parameter of the CG-Retransmission Timer based on resource priority. For deprioritized resources, the start time parameter is shifted from the beginning of the first symbol to the end of the last symbol, enabling automatic retransmission while maintaining straightforward operation through clear conditional logic.
Data Source
AI summary
A transmission method and a terminal device are provided. The transmission method includes: when configuring a configured grant retransmission timer, a terminal device determining a hybrid automatic repeat request process and/or the state of the timer on the basis of a satisfied condition. By means of the embodiments of the present application, the transmission delay of a resource, especially a low-priority resource, can be reduced.