HARQ-ACK Bit Grouping by Retransmission Number for Better Decoding
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Solution Overview
Problem
Current HARQ feedback solutions lack mechanisms to utilize grouping for channel coding gains and decoding improvements, as they are limited to marginal distributions of HARQ feedback bits, leading to performance loss.
Innovation Solution
Grouping HARQ-ACK bits based on retransmission number, where a first set of bits is mapped with a first BLER target and a second set of bits is mapped with a lower BLER target, allowing for improved decoding by aligning bits with the same distribution during channel code mapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ feedback bits are transmitted without grouping based on retransmission number, then the transmission process is simple, but coding gains are lost and decoding performance deteriorates
Solution Approach 1:
The patent segments HARQ feedback bits into different groups based on their retransmission number (e.g., first retransmission bits, second retransmission bits, etc.). This segmentation allows each group to be encoded independently with appropriate coding parameters, improving decoding performance by accounting for the different reliability characteristics of bits from different retransmission attempts while maintaining manageable coding complexity through structured organization.
2Reliability
If all HARQ feedback bits are treated with the same BLER target, then the coding process is simple, but performance is lost due to ignoring distribution differences
Solution Approach 1:
The patent applies different BLER targets and coding parameters to different groups of HARQ feedback bits based on their retransmission number. Specifically, bits from the first retransmission are assigned a first BLER target, while bits from the second retransmission are assigned a second (lower) BLER target. This local differentiation optimizes reliability for each bit group according to its specific distribution characteristics, improving overall HARQ feedback reliability while maintaining reasonable coding adaptability through a structured approach.
Data Source
AI summary
Grouping HARQ-ACK bits based on retransmission number is described. An apparatus is configured to identify sets of bits associated with HARQ feedback for a DL transmission from a network node. A first set of bits is associated with a first HARQ feedback transmission and a second set of bits is associated with a second HARQ feedback transmission for the DL transmission. The apparatus is configured to map the first set of bits as a first grouping and the second set of bits as a second grouping, which is different than the first grouping, to a coding for an UL channel. The apparatus is configured to transmit, to the network node and with the coding via the UL channel, an indication of the first set of bits and the second set of bits in accordance with the first grouping and the second grouping.