Feedback Method for Partial Code Block Retransmission
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Solution Overview
Problem
In LTE systems, retransmission of data blocks (TBs) is inefficient due to the need to retransmit entire blocks even when only some Code Blocks (CBs) are incorrectly received, leading to high resource utilization and overhead.
Innovation Solution
A feedback method that divides TBs into multiple CB sets, allowing for partial retransmission of incorrectly received CBs based on specific feedback information (ACK/NACK) to minimize retransmitted data volume and improve efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the entire TB is retransmitted when any CB is incorrectly received, then reliability of data reception is improved, but resource utilization deteriorates due to high retransmission overhead
Solution Approach 1:
The patent segments the TB into multiple CB sets (e.g., CB set 1, CB set 2, etc.) and applies separate CRC checks to each CB set. This allows the system to identify and retransmit only the specific incorrect CB sets rather than the entire TB, resolving the contradiction by maintaining reliability through accurate error detection while reducing resource overhead through targeted retransmission.
Solution Approach 2:
The patent applies different treatment to different CB sets based on their individual CRC check results. Correct CB sets are not retransmitted while incorrect CB sets are retransmitted with appropriate redundancy. This local differentiation resolves the contradiction by ensuring reliable reception of only the necessary data portions while minimizing overall retransmission resources.
2Productivity
If CB-based feedback is implemented to enable partial retransmission, then retransmission efficiency is improved, but feedback overhead increases extremely high
Solution Approach 1:
The patent merges multiple CB sets into larger groups and provides feedback at the CB set level rather than individual CB level. For example, multiple CBs are grouped into CB sets, and a single NACK indicates all incorrect CB sets in a group. This merging approach maintains retransmission efficiency by enabling partial retransmission while significantly reducing feedback overhead compared to individual CB feedback.
Solution Approach 2:
The patent uses a simplified feedback mechanism that provides partial information about error locations rather than complete CB-level details. The feedback indicates which CB sets are incorrect without providing exhaustive information about every single erroneous CB, achieving a balance between retransmission efficiency and feedback overhead by providing just enough information for targeted retransmission.
3Reliability
If multiple CRCs are added to each CB and TB for error detection, then reliability of error detection is improved, but device complexity increases
Solution Approach 1:
The patent segments the error detection function by applying CRC checks at the CB set level rather than requiring complex individual CB-level checks for all CBs. Each CB set has its own CRC, allowing the system to maintain high error detection reliability while reducing the overall complexity by processing CB sets as unified units rather than individual CBs.
Solution Approach 2:
The CB set CRC serves multiple functions: it detects errors in the CB set, identifies which CB sets need retransmission, and enables efficient feedback generation. This multi-functionality maintains high error detection reliability while reducing device complexity by eliminating the need for separate complex checking mechanisms for each individual CB.
Data Source
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AI summary
Provided are a feedback method and a feedback device. The method includes that: a first transmission node receives a signal including a Transmission Block (TB) from a second transmission node; the first transmission node obtains states of the P CB sets according to the signal including the TB; the first transmission node determines at least one kind of feedback information in a preset feedback information set according to the states of the P CB sets; and the first transmission node sends the determined feedback information to the second transmission node, where the feedback information set further includes CB error patterns of incorrect CB sets, or a CB error pattern of the TB.