Rate-Compatible LDPC Encoding for IR-HARQ Redundancy
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Solution Overview
Problem
Current WLAN systems face limitations in supporting IR-HARQ transmission due to the lack of rate-compatible LDPC code check matrices, which restricts the introduction of new incremental redundant bits necessary for reducing channel coding rates.
Innovation Solution
The proposed solution involves an LDPC encoding method that utilizes a rate-compatible LDPC code check matrix to implement IR-HARQ transmission. This is achieved by extracting appropriate submatrices from a larger check matrix H, which supports a range of transmission code rates, thereby enabling the introduction of new incremental redundant bits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a rate-compatible LDPC code check matrix is introduced to support IR-HARQ transmission, then the ability to introduce new incremental redundant bits is improved, but the device complexity increases
Solution Approach 1:
The check matrix H is segmented into multiple submatrices including HMC (mother code submatrix), HIR (incremental redundancy submatrix), and identity matrix submatrices. This segmentation allows the system to selectively use different submatrices for different transmission scenarios, enabling rate-compatible LDPC coding while managing complexity through modular structure.
Solution Approach 2:
The patent implements dynamic selection of check matrix submatrices based on transmission requirements. The transmit end can dynamically choose different submatrices from the check matrix H to generate codewords with different code rates, enabling adaptive modulation and coding for IR-HARQ operations.
2Adaptability or versatility
If multiple check matrixes are supported to enable different code rates, then the adaptability for different transmission scenarios is improved, but the ease of operation deteriorates
Solution Approach 1:
The check matrix H serves multiple functions by containing different submatrices that can be used for different code rates and transmission scenarios. Instead of maintaining separate check matrixes for each code rate, the universal check matrix H can generate codewords for various rates through selective submatrix usage, simplifying system operation.
Solution Approach 2:
The check matrix H is pre-configured with multiple submatrices (HMC, HIR, identity matrices) that are prepared in advance for different transmission scenarios. This preliminary setup allows the system to quickly switch between different code rates without complex real-time calculations, improving ease of operation.
3Reliability
If incremental redundant bits are accumulated through multiple retransmissions, then the decoding performance is improved, but the loss of time increases
Solution Approach 1:
The patent enables continuous accumulation of incremental redundant bits across multiple retransmissions without requiring complete retransmission of original data. The receive end continuously updates the combined codeword by adding new redundant bits from each retransmission, maintaining useful action throughout the retransmission process and reducing overall time loss.
Data Source
AI summary
The present disclosure relates to low-density parity-check (LDPC) encoding methods and apparatus. One example method includes obtaining k information bits to be sent to a receive end, performing LDPC encoding on the k information bits by using a submatrix of ((n−k)/Z+j) rows and (n/Z+j) columns at an upper left corner of a check matrix H based on a first transmission code rate R satisfying R=k/(n+j×Z), obtaining a first codeword including the k information bits and (n−k+j×Z) redundant bits, and sending the first codeword to the receive end.