Configured Grant Timer for Deprioritized Data Retransmission
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Solution Overview
Problem
In new radio (NR) systems, deprioritized MAC PDUs are often lost due to conflicts in time-domain resource allocation, leading to data loss, as they are either not retransmitted or flushed when a higher priority data needs to be transmitted.
Innovation Solution
A wireless communication method where a terminal device determines, based on the state of a configured grant timer, whether to retransmit deprioritized data and identifies a target resource location for retransmission, avoiding conflicts with network device retransmission scheduling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a base station schedules transmission of eMBB service on UL grant and then schedules transmission of URLLC on another UL grant, then the terminal can transmit higher priority data, but the deprioritized MAC PDU is stored in buffer and may be flushed resulting in data loss
Solution Approach 1:
The terminal device determines in advance whether to retransmit deprioritized data by checking if a configured grant resource occurs within a specific time window after the configured grant timer expires. This preliminary determination prevents data loss by proactively scheduling retransmission before the data is flushed from the buffer.
Solution Approach 2:
The system dynamically adjusts the handling of deprioritized data based on the terminal's transmission status. When the terminal determines it has transmission opportunities (configured grant resources) available, it autonomously decides to retransmit deprioritized data, creating a dynamic adaptation mechanism that responds to real-time channel conditions and resource availability.
2Reliability
If the terminal device autonomously determines retransmission of deprioritized data, then data loss probability is reduced, but conflict may occur with network device retransmission scheduling
Solution Approach 1:
The configured grant timer and configured grant resources serve as intermediary mechanisms that coordinate between the terminal's autonomous decisions and the network's scheduling. The timer expiration triggers the terminal's retransmission determination, while the configured grant resources provide pre-allocated transmission opportunities, acting as a mediator that prevents direct conflict between terminal and network scheduling decisions.
Solution Approach 2:
The terminal device autonomously determines whether to retransmit deprioritized data based on its own transmission status and available resources, without requiring continuous network intervention. This self-service approach reduces coordination overhead while maintaining reliability, as the terminal independently manages its retransmission decisions within the framework of pre-configured resources.
3Loss of time
If deprioritized data is not retransmitted timely, then transmission delay increases, but if retransmission is scheduled without proper timing mechanism, then data loss occurs
Solution Approach 1:
The system pre-configures grant resources and establishes a timer mechanism that triggers retransmission determination at a specific time point. This preliminary setup ensures that retransmission is initiated timely without ad-hoc scheduling delays, while the configured resources guarantee that transmission opportunities are available, preventing both delay and data loss.
Solution Approach 2:
The configured grant timer introduces a time parameter that dynamically controls the retransmission decision process. By changing the timer expiration time and configuring appropriate grant resource intervals, the system optimizes the balance between timely retransmission and data availability, adjusting parameters to meet both delay requirements and reliability constraints.
Data Source
AI summary
A wireless communication method, a terminal device and a network device, the method includes: a terminal device determines, according to first information, whether to retransmit deprioritized data on a configured grant resource and/or determines a target resource location for retransmitting the deprioritized data, where the first information includes at least one of the following: a running state of a configured grant timer; a configured grant resource location after the configured grant timer is started; whether the deprioritized data is scheduled during a first time period after the configured grant timer is started; whether the deprioritized data is transmitted during a second time period after the configured grant timer is started; whether the deprioritized data is cleared during a third time period after the configured grant timer is started.