HARQ Retransmission Resource Reservation Under Buffer Constraints
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently managing HARQ buffer utilization, latency, and resource allocation for retransmissions, particularly in multi incremental redundancy schemes, leading to increased buffer utilization and resource inefficiencies.
Innovation Solution
The techniques involve calculating average metrics from log likelihood ratios (LLRs) to determine sufficient resources for retransmissions, monitoring HARQ buffer utilization, and adjusting resource allocation based on latency levels and buffer thresholds to optimize retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional redundancy bits are added for each retransmission, then reliability of code block delivery is improved, but HARQ buffer utilization increases
Solution Approach 1:
The patent changes the parameter of coding rate dynamically based on buffer conditions. When buffer utilization exceeds the threshold, the system selects a second coding rate that uses repetition instead of adding redundancy bits, thereby maintaining reliability while reducing buffer consumption.
Solution Approach 2:
The patent introduces dynamic switching between two different coding rates based on real-time buffer utilization monitoring. The network entity adapts the coding scheme from incremental redundancy (first coding rate) to repetition (second coding rate) when buffer thresholds are exceeded, making the system flexible and responsive to buffer conditions.
2Loss of time
If more resources are allocated for retransmissions, then latency is reduced, but resource allocation efficiency deteriorates
Solution Approach 1:
The patent changes the resource allocation parameter dynamically by selecting different coding rates based on buffer conditions. When buffer utilization is high, the system switches to repetition coding which uses existing resources more efficiently rather than allocating additional resources, thereby maintaining low latency while improving resource efficiency.
Solution Approach 2:
The patent implements a feedback mechanism where the network entity monitors HARQ buffer utilization and adjusts resource allocation for retransmissions accordingly. When buffer utilization exceeds the threshold, the system receives feedback and switches to a more resource-efficient coding rate, optimizing resource allocation based on real-time system state.
3Productivity
If incremental redundancy scheme is used for retransmissions, then coding efficiency is improved, but HARQ buffer management complexity increases
Solution Approach 1:
The patent segments the coding scheme into two distinct modes: incremental redundancy (first coding rate) for normal operations and repetition (second coding rate) for buffer-constrained scenarios. This segmentation allows the system to switch between simple and efficient modes based on buffer conditions, managing complexity while maintaining efficiency.
Solution Approach 2:
The patent introduces dynamic switching between coding schemes based on buffer utilization thresholds. When the threshold is exceeded, the system transitions from incremental redundancy to repetition coding, simplifying buffer management while maintaining coding efficiency through adaptive selection of the appropriate coding mode.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A network entity may determine a number of resources for next transmissions following a first transmission. For example, a user equipment (UE) may calculate an average mutual information (MI) of a single log likelihood ratio (LLR) and an MI for each code block. The UE may transmit feedback indicating a quantity of resources to achieve a target MI based on the calculated averages. A wireless device may monitor a feedback buffer utilization associated with the UE. A network entity may retransmit existing code blocks or output a transmission using repetition based on the monitoring and utilization thresholds. The network entity may indicate to the UE a latency level code block attribute and increase a quantity of resources for following retransmissions by a boosting factor based on the latency level and a threshold.