NR RLC Segment Concatenation for Retransmission Overhead Reduction
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Solution Overview
Problem
Current wireless communication technologies face challenges in efficiently retransmitting NACKed SDU segments due to unclear methods for re-segmentation, leading to increased overhead and delays in 3GPP NR and LTE networks.
Innovation Solution
The solution involves considering the size of the gap segment adjacent to NACKed SDU segments to determine when and how to concatenate them for retransmission, minimizing overhead by optimizing header sizes and reducing the need for re-segmentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple NACKed SDU segments are retransmitted separately, then each segment can be individually acknowledged, but retransmission overhead increases due to multiple headers
Solution Approach 1:
The patent combines multiple NACKed SDU segments into a single retransmission PDU when they are adjacent in the SDU structure. This merging eliminates the need for separate headers for each segment, reducing overall retransmission overhead while maintaining reliable delivery through consolidated acknowledgment mechanisms.
2Productivity
If gap segments are included in retransmission concatenation, then fewer retransmission packets are needed, but complexity of determining concatenation conditions increases
Solution Approach 1:
The patent applies different handling rules to different types of segments based on their position and acknowledgment status. Gap segments (non-NACKed segments between NACKed segments) are conditionally included in concatenation based on specific size comparisons, while NACKed segments are always included. This localized quality approach simplifies the overall decision logic by creating clear, position-based rules.
Solution Approach 2:
The patent uses parameter-based decision making where the inclusion of gap segments in retransmission concatenation is determined by comparing segment sizes against threshold values. When the gap segment size exceeds certain parameters relative to adjacent NACKed segments, concatenation is adjusted. This parameter-driven approach transforms complex logical decisions into manageable numerical comparisons.
3Quantity of substance
If re-segmentation is applied to fit transport block size, then transmission capacity is optimized, but retransmission delays increase
Solution Approach 1:
The patent performs preliminary assessment of segment concatenation opportunities before retransmission. By evaluating the sizes of NACKed segments and adjacent gap segments in advance, the system determines optimal concatenation strategies that fit transport block constraints, avoiding the need for time-consuming re-segmentation operations during actual retransmission and thus reducing delays.
Data Source
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AI summary
Transmitters consider the size of a gap segment adjacent to at least one negatively acknowledged (NACKed) Radio Link Control (RLC) Service Data Unit (SDU) when considering when and/or how to concatenate one or more NACKed SDU segments for retransmission. Depending on which RLC SDU segment(s) is/are NACKed, e.g., considering the size of NACKed segments in relation to Protocol Data Unit (PDU) header size(s) needed, the transmitter implements a single RLC SDU retransmission or multiple RLC SDU segment retransmissions. In so doing, the solution presented herein not only defines how such transmissions occur, but also provides improved efficiency when retransmitting such NACKed SDU segments.