QC-LDPC Parity Check Matrix for Low-Complexity 1/2-Rate Encoding
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Solution Overview
Problem
Existing LDPC codes face challenges with computationally intensive encoding processes due to high-density generator matrices, limiting their practical application, especially in wireless communication systems like IEEE 802.11 standards, where the longest supported block length is 1944 bits, and there is limited gain in radio channels.
Innovation Solution
Implementing a quasi-cyclic-low-density parity-check (QC-LDPC) code with a block length of 3888 bits and a code rate of 1/2, utilizing a parity check matrix with a quasi-cyclic structure, which simplifies encoding and decoding processes by using a parity check matrix derived from an exponent matrix with cyclic shift values, allowing for efficient encoding and decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-density generator matrix is used for LDPC encoding, then encoding accuracy is improved, but computational complexity increases significantly
Solution Approach 1:
The patent segments the generator matrix into multiple sub-matrices with a quasi-cyclic structure, where each sub-matrix can be processed independently. This segmentation reduces the computational burden of encoding operations while maintaining the error correction performance of the original high-density generator matrix.
Solution Approach 2:
The patent transforms the generator matrix from a completely dense structure to a quasi-cyclic structure with specific parameter patterns. By changing the structural parameters of the matrix (introducing cyclic shifts and repeating patterns), the encoding complexity is reduced while preserving the reliability properties through careful design of the sub-matrix dimensions and shift values.
2Reliability
If the block length is increased beyond 1944 bits, then coding gain in radio channels is improved, but compatibility with existing standards is reduced
Solution Approach 1:
The patent implements a dynamic block length configuration that can adapt between different code block sizes. The QC-LDPC code structure allows flexible selection of block lengths (including 3888 bits) while maintaining compatibility with existing standardization frameworks through configurable parameters such as lifting size and sub-matrix dimensions, enabling both extended performance and standard compliance.
Solution Approach 2:
The patent designs a universal QC-LDPC encoding framework that can function across multiple block length configurations. The same quasi-cyclic structure with configurable parameters serves both the extended 3888-bit block length for improved coding gain and can be adapted to shorter block lengths for standard compatibility, making the solution multi-functional across different application scenarios.
3Productivity
If a quasi-cyclic structure is implemented in the parity check matrix, then encoding efficiency is improved, but design complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-defining the quasi-cyclic structure parameters (sub-matrix size, cyclic shift values, and lifting factor) during the code design phase. These pre-configured parameters enable efficient encoding operations without requiring complex real-time calculations, as the structural patterns are established in advance and can be directly applied during encoding.
Solution Approach 2:
The patent utilizes copying by repeating identical sub-matrices throughout the parity check matrix according to the quasi-cyclic structure. Instead of designing each sub-matrix independently, the same base sub-matrix is copied and cyclically shifted to populate the entire matrix, significantly reducing the design complexity while maintaining the efficiency benefits of the quasi-cyclic structure.
Data Source
AI summary
In some implementations, an apparatus may include a transmitter and one or more processors. The one or more processors may be configured to identify, according to a code rate of 1/2 and a code block size of 3888 bits, a first binary parity check matrix for a quasi-cyclic-low-density parity-check (QC-LDPC) code. The first binary parity check matrix may correspond to a first exponent matrix having 288 values. The one or more processors may be configured to encode data using the first binary parity check matrix. The one or more processors may be configured to transmit the encoded data.