Adaptive Retransmission Control for 5G UEs Under Tight Delay Constraints
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems, particularly in 5G NR, transmissions with very short periodicity and tight delay requirements make multiple retransmissions impractical, leading to power inefficiency and potential reduction in successful packet decoding rates when naive extensions of HARQ Mode B are applied to communication flows with tight delay budgets.
Innovation Solution
A method and apparatus that adaptively disable or enable retransmissions based on experienced packet delay at the UE, allowing retransmissions when delay budgets are met while avoiding unnecessary overhead when they are not, by identifying characteristic times associated with UL and DL transmissions exceeding threshold times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retransmission capability is enabled for all transmissions, then packet decoding success rate is improved, but power consumption increases and delay requirements cannot be met
Solution Approach 1:
The retransmission capability is made dynamic rather than static. The system automatically adjusts the retransmission state based on real-time measurement of characteristic times (such as transmission time, processing time, or delay budget). When the measured characteristic time exceeds the threshold, retransmission is disabled to save power; when it is within the threshold, retransmission is enabled to maintain reliability. This dynamic adaptation resolves the contradiction between reliability and power consumption.
Solution Approach 2:
The system changes the operational parameter of retransmission capability based on the characteristic time parameter. By monitoring whether the characteristic time (e.g., time to transmit and process data) exceeds a predefined threshold, the system switches the retransmission parameter between enabled and disabled states. This parameter-based control allows the system to optimize both reliability and power consumption according to actual transmission conditions.
2Use of energy by moving object
If retransmission capability is disabled to save power, then power consumption is reduced, but packet decoding success rate deteriorates
Solution Approach 1:
The system implements feedback control by continuously monitoring the characteristic time of transmissions and using this information to adjust the retransmission capability. The feedback loop measures whether the characteristic time exceeds the threshold and automatically adjusts retransmission accordingly. This feedback mechanism ensures that retransmission is disabled only when necessary (when delay budgets are exceeded), thereby saving power while maintaining high packet decoding success rates when transmission conditions are favorable.
3Device complexity
If fixed retransmission policy is applied, then system complexity is reduced, but adaptability to different communication conditions deteriorates
Solution Approach 1:
The system performs self-adjustment based on its own measured characteristics. Instead of requiring complex external control or configuration, the system autonomously monitors its own transmission timing and processing characteristics, compares them against the threshold, and independently decides whether to enable or disable retransmission. This self-service approach maintains relatively simple system complexity while achieving high adaptability to different communication conditions and delay constraints.
Data Source
AI summary
An apparatus that may be a user equipment (UE) configured to identify that at least one characteristic time associated with a first uplink (UL) transmission is greater than a threshold time and to disable, based on the at least one characteristic time with the first UL transmission being greater than the threshold time, a retransmission capability. In some aspects, the apparatus may be a network node configured to identify that at least one characteristic time associated with a first downlink (DL) transmission is greater than a threshold time and to disable, based on the at least one characteristic time with the first DL transmission being greater than the threshold time, a retransmission capability.