LDPC Parity-Check Matrix Layout with Multi-Direction Base Shifts
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Solution Overview
Problem
Existing LDPC code constructions in 5G New Radio (NR) mobile communications are inefficient due to the use of a base matrix with limited cyclic shifts, which hampers performance improvement.
Innovation Solution
The proposed method involves determining a first base matrix and multiple second base matrices by shifting elements along column and row directions, followed by constructing a parity-check matrix using these matrices to enhance LDPC performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a base matrix with limited cyclic shifts is used in LDPC code construction, then the device complexity is reduced, but the LDPC performance deteriorates
Solution Approach 1:
The base matrix is segmented into multiple sub-matrices (first base matrix and second base matrices), where each sub-matrix can be independently constructed with specific cyclic shift properties. This segmentation allows the system to achieve better overall LDPC performance through optimized sub-matrix structures while managing complexity through modular construction.
Solution Approach 2:
The patent introduces dynamic cyclic shift operations on the base matrix elements. By applying different cyclic shifts to different sub-matrices and columns, the system dynamically adjusts the base matrix structure to optimize LDPC performance for different channel conditions and code rates, rather than using a fixed limited-shift structure.
2Reliability
If multiple second base matrices are generated by shifting elements along column and row directions, then the LDPC performance is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent extends the base matrix construction from a single two-dimensional matrix to multiple two-dimensional matrices (first base matrix and multiple second base matrices). By adding the dimension of multiple matrices, the system can achieve better LDPC performance through diversified matrix structures while distributing the precision requirements across multiple independent matrices rather than demanding extreme precision in a single matrix.
Solution Approach 2:
The patent systematically varies parameters such as cyclic shift amounts, shift directions (column-wise, row-wise, or both), and matrix dimensions when generating the second base matrices from the first base matrix. These parameter changes create diversity in the base matrix structures, improving LDPC performance while using controlled, discrete parameter adjustments rather than requiring continuous high-precision positioning.
Data Source
Figure 1~2A
Figure 2B~2C
Figure 2D~2E
AI summary
Various solutions for improving LDPC with respect to an apparatus in mobile communications are described. The apparatus may determine a first base matrix corresponding to a parity-check matrix of LDPC (1210). The apparatus may determine a plurality of second base matrices based on the first base matrix by shifting a plurality of elements of the first base matrix along at least one of column-direction and row-direction, wherein a value of each element is one (1220). The apparatus may determine the parity-check matrix according to the first base matrix and the second base matrices (1230). The size of the first base matrix is Z by Z, the first base matrix has Z elements while a value of each element is 1 and (0,0) of the first base matrix is set to be empty or 0. The number of second base matrices is Z-2.