HARQ-ACK Signal Mapping for Wireless Retransmission
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Solution Overview
Problem
In wireless communication systems, existing methods for transmitting HARQ-ACK signals are inefficient, particularly in scenarios requiring retransmissions of code blocks, leading to increased latency and reduced communication capacity.
Innovation Solution
The method involves mapping code block groups to HARQ-ACK signals in ascending order, with only negative-acknowledgement signals being mapped to the first HARQ-ACK signal, and transmitting both HARQ-ACK signals over different channels, including the option of piggybacking the first HARQ-ACK signal on an uplink data channel, and incorporating a cyclic redundancy check for error detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HARQ-ACK signals are transmitted for all code blocks, then reliability is improved, but signaling overhead increases
Solution Approach 1:
The patent segments code blocks into code block groups (CBGs) and transmits HARQ-ACK feedback at the CBG level rather than individual CB level. This segmentation allows the system to provide fine-grained retransmission feedback while reducing the total number of ACK/NACK signals compared to per-CB feedback, thereby reducing signaling overhead while maintaining reliability through selective retransmission of only erroneous CBGs.
Solution Approach 2:
The patent applies partial action by transmitting HARQ-ACK feedback only for code block groups that require retransmission (NACK) or for selected CBGs based on configuration, rather than transmitting feedback for all code blocks. This selective feedback approach reduces signaling overhead while maintaining sufficient reliability for data retransmission.
2Manufacturing precision
If code block level feedback is implemented, then retransmission precision is improved, but device complexity increases
Solution Approach 1:
The patent introduces code block groups as an intermediate segmentation level between individual code blocks and transport blocks. This segmentation simplifies the feedback processing complexity by reducing the number of individual feedback signals from per-CB level to per-CBG level, while still maintaining precise retransmission control for specific erroneous code blocks through the grouped feedback mechanism.
Solution Approach 2:
The patent designs the CBG-based feedback mechanism to serve multiple functions: it provides fine-grained retransmission precision like CB-level feedback, reduces signaling overhead compared to CB-level feedback, and maintains compatibility with existing transport block-level retransmission mechanisms. This multi-functionality reduces the need for separate complex processing paths for different feedback granularities.
3Reliability
If multiple HARQ-ACK signals are transmitted over different channels, then reliability is improved, but use of energy increases
Solution Approach 1:
The patent dynamically selects the transmission channel for HARQ-ACK signals based on channel conditions and configuration. The first HARQ-ACK signal can be transmitted on PUCCH or PUSCH depending on uplink data presence and channel conditions, while the second HARQ-ACK signal is transmitted on PHICH or PUSCH. This dynamic channel selection optimizes energy usage by adapting to varying channel conditions while maintaining transmission reliability through multiple path options.
Solution Approach 2:
The patent changes transmission parameters including channel selection (PUCCH/PUSCH/PHICH), timing (K1 offset), and signal format based on traffic conditions and channel quality. These parameter changes allow the system to transmit multiple HARQ-ACK signals with optimized energy consumption by selecting the most efficient transmission path for each signal while maintaining reliability through diversity.
Data Source
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AI summary
The present invention discloses a method for a terminal receiving re-transmitted data in a wireless communication system. In particular, the method may comprise the steps of: receiving from a base station a plurality of transport blocks that include a plurality of code block groups; the respective code block groups mapping and transmitting first HARQ-ACK signals with respect to the respective plurality of code block groups on the basis of an order in which the respective plurality of transport blocks are received, and an order that is included in the respective plurality of transmission blocks; and receiving one or more code block groups that are re-transmitted based on the transmitted first HARQ-ACK signals.