MAC HARQ Selective LDPC Retransmission to Cut Wireless Overhead
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Solution Overview
Problem
Current Hybrid Automatic Repeat Request (HARQ) systems in wireless data transmission are inefficient due to the need for retransmitting multiple codewords, which increases overhead and processing demands, especially when dealing with frames larger than a minimum size requirement.
Innovation Solution
Implementing a Media Access Control (MAC)-based HARQ that allows for selective retransmission of codewords by using block acknowledgments to identify and retransmit only necessary codewords, reducing unnecessary retransmissions and optimizing feedback signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all codewords are retransmitted in HARQ, then reliability of data reception is improved, but overhead and processing demands increase
Solution Approach 1:
The patent segments the retransmission process by dividing codewords into different priority groups (first priority and second priority). Instead of uniformly retransmitting all codewords, the system selectively retransmits only those codewords that are necessary for maintaining data reception reliability, thereby reducing processing complexity while preserving reliability for critical data.
Solution Approach 2:
The patent applies local quality by assigning different retransmission priorities to different codewords based on their importance. First priority codewords receive guaranteed retransmission to ensure reliability, while second priority codewords are retransmitted only when resources permit. This differentiated approach maintains reliability for essential data while reducing overall processing demands.
2Reliability
If multiple codewords are retransmitted, then error correction capability is improved, but overhead increases
Solution Approach 1:
The patent extracts and identifies specific codewords that require retransmission based on their priority level and reception status. By taking out only the necessary codewords (first priority uncoded data) for retransmission rather than all codewords, the system maintains error correction capability for critical information while reducing the quantity of retransmitted data and associated overhead.
Solution Approach 2:
The patent implements partial action by retransmitting only a subset of codewords (those with first priority) rather than all codewords. This selective approach provides sufficient error correction capability for the most important data while avoiding the excessive overhead that would result from retransmitting all codewords regardless of their importance.
3Quantity of substance
If selective retransmission of codewords is implemented, then overhead is reduced, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by assigning priority levels to codewords before transmission. This pre-classification of codewords into first and second priority groups enables selective retransmission without requiring complex real-time decisions during the retransmission phase. The preliminary prioritization simplifies the control logic by establishing clear retransmission rules based on pre-determined priorities.
Solution Approach 2:
The patent introduces dynamic adaptability by allowing the transmitter to flexibly determine which codewords to retransmit based on current system conditions, such as buffer status and resource availability. The selective retransmission mechanism dynamically adjusts the retransmission set by combining first priority uncoded data with optionally selected second priority coded data, optimizing overhead reduction while managing control complexity through structured decision rules.
Data Source
AI summary
Some embodiments of this disclosure include apparatuses and methods for a media access control (MAC) level operation that enables a transmitter and a receiver to select low-density parity check (LDPC) codewords that are HARQ retransmitted. The operations described herein provide for reducing the number of codewords that need to be retransmitted, minimizing the overhead needed to signal the feedback from a receiver to a transmitter, and allowing a transmitter to control which codewords are retransmitted.