HARQ Rate Matching with Variable Bit Selection Coverage

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Solution Overview

Problem

The probability of overlapping phenomena is high in existing rate matching processes, leading to inefficient data transmission and reduced system performance in HARQ retransmissions.

Innovation Solution

A method and device that change the manner of selecting bits from the mother code codeword to generate HARQ subpackets, ensuring comprehensive coverage of the mother code data and minimizing overlapping, by employing various approaches for determining the start position of the subpacket, such as selecting from the first, last, or middle positions of the codeword.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the conventional rate matching algorithm is used to select bits from the mother code codeword, then the implementation is simple, but the overlapping phenomena occurs frequently leading to poor transmission efficiency

Engineering Contradiction:
Improveimplementation simplicityVSAvoidtransmission efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent changes the parameter of bit selection by introducing a variable step length that adapts based on the current transmission attempt. Instead of using a fixed or simple sequential selection method, the step length is dynamically adjusted to skip over previously transmitted bits, thereby reducing overlapping phenomena while maintaining implementation feasibility.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If bits are selected sequentially from the mother code codeword, then the selection process is simple, but the coverage of mother code data is insufficient and overlapping occurs

Engineering Contradiction:
Improvebit selection processVSAvoiddata coverage
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent introduces dynamic behavior to the bit selection process by making the step length variable rather than fixed. The step length changes based on the transmission context, allowing the selection process to adaptively cover more of the mother code data while avoiding overlapping. This dynamic approach improves reliability without significantly complicating the operation.

Inventive Principle:
Principle #15Dynamics

3Stability of the object's composition

If the same start position is used for HARQ retransmissions, then the process is consistent and simple, but the overlapping phenomena reduces system performance

Engineering Contradiction:
Improvetransmission consistencyVSAvoidsystem performance
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The patent applies preliminary action by calculating and determining the step length before the actual bit selection process. This pre-determined step length is designed to prevent overlapping by skipping over bits that have already been transmitted in previous attempts. This approach maintains consistency in the process while improving system performance through better data coverage.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3553981A1Rate matching method and device
Publication Date: 2019.10.16 ZTE CORP
  • EP3553981A1 patent drawingFigure 1~2
  • EP3553981A1 patent drawingFigure 3~4
  • EP3553981A1 patent drawingFigure 5

AI summary

The present invention discloses a rate matching method and device. The method includes that: an information bit sequence is coded and interleaved to obtain a mother code codeword with a length NFB_Buffer; and bits are selected from the mother code codeword to generate a hybrid automatic repeat request (HARQ) subpacket for current transmission. By means of the present invention, the effect of covering the whole mother code area can be achieved as much as possible, and the performance of the HARQ multiple retransmission link can be enhanced.