Configured Grant Timer Stopping for Uplink Retransmission
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Solution Overview
Problem
In wireless communication systems, there is a challenge in managing configured grant (CG) timers to ensure efficient retransmission of uplink data without expiring, particularly due to limited resources and the need to prevent new transmissions during timer operation.
Innovation Solution
A method where a user equipment (UE) starts both a CG timer and a CG retransmission timer for an HARQ process, and upon expiration of the CG retransmission timer, the CG timer is stopped if no retransmission opportunity is available until the expected expiration time of the CG timer, allowing retransmission after the CG timer expires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the CG timer is allowed to expire normally, then the UL resource allocation is simplified, but the retransmission reliability deteriorates when no retransmission opportunity is available
Solution Approach 1:
The system performs preliminary action by stopping the CG timer before its expiration when retransmission opportunity is unavailable. This proactive timer management ensures that the UL resource is not wasted and can be reallocated, while maintaining retransmission reliability through coordinated HARQ process management. The base station proactively identifies when no retransmission opportunity exists and intervenes to stop the timer, preventing the resource allocation problem before it occurs.
2Reliability
If the CG timer is stopped before expiration, then the retransmission reliability is improved, but the timer management complexity increases
Solution Approach 1:
The system implements feedback mechanisms where the base station monitors the CG timer status and retransmission opportunity availability, then provides feedback by sending control signals to stop the CG timer when appropriate. This feedback loop ensures that timer management decisions are made based on real-time system state, improving retransmission reliability while minimizing unnecessary timer operations. The base station uses HARQ ACK/NACK feedback and uplink resource availability information to make informed timer management decisions.
3Reliability
If UL resources are allocated for retransmission, then the retransmission reliability is improved, but the resource utilization efficiency deteriorates when retransmission is not needed
Solution Approach 1:
The system applies dynamics by making UL resource allocation flexible and conditional rather than static. The base station dynamically determines whether to allocate UL resources for retransmission based on real-time assessment of retransmission necessity. When the CG timer is stopped before expiration and no retransmission opportunity exists, the system dynamically adjusts resource allocation to avoid wasting resources on unnecessary retransmissions, thereby maintaining high resource utilization efficiency while ensuring retransmission reliability when actually needed.
Data Source
AI summary
The present invention relates to a method of transmitting uplink (UL) data by a user equipment (UE) in a wireless communication system. In particular, the method includes the steps of: based on the UE transmitting the UL data on a first UL resource of a configured grant (CG) con-figuration based on a Hybrid-ARQ (HARQ) process, starting a CG retransmission timer for the HARQ process and a CG timer for the HARQ process; based on a second UL resource of the CG configuration not being configured between an expiration time point of the CG retransmission timer and an expected expiration time point of the CG timer, stopping the CG timer upon expiration of the CG retransmission timer; and performing retransmission of the UL data based on the HARQ process after the expected expiration time point of the CG timer.