Lifted LDPC Parity Check Matrix Layout for Low-Delay Decoding
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently encoding and decoding data at high rates, particularly in multiple-access technologies like 5G New Radio (NR), where errors in data transmission can lead to unusable data and the need for retransmission, and existing LDPC codes struggle with complexity and cost-effectiveness for wide implementation.
Innovation Solution
The implementation of a method and apparatus for performing low-density parity-check (LDPC) decoding and encoding using a parity check matrix with row orthogonality, specifically designed for lifted LDPC codes, which enables efficient decoding and encoding by ensuring row orthogonality between consecutive rows connected to punctured variable nodes, thereby reducing processing delays and improving decoding performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If LDPC decoding is performed using conventional parity check matrices without row orthogonality, then the decoding process can be implemented, but processing delays increase and decoding performance deteriorates due to outdated variable check sums
Solution Approach 1:
The patent applies preliminary action by ensuring that variable check sums are updated before they are needed in subsequent decoding operations. The row orthogonality condition guarantees that when decoding row i, all variable check sums required for that row have already been updated by previous rows, eliminating waiting delays and ensuring up-to-date information is always available.
Solution Approach 2:
The patent introduces dynamics by changing the structure and ordering of rows in the parity check matrix. Instead of using a fixed conventional structure, the rows are dynamically arranged to satisfy the row orthogonality condition, where each row is orthogonal to subsequent rows that share variable nodes. This dynamic reorganization enables continuous updating of variable check sums without stalling the decoding process.
2Productivity
If LDPC codes are designed for high-rate data transmission, then transmission speed increases, but complexity of encoding and decoding processes increases, making implementation more costly
Solution Approach 1:
The patent applies segmentation by dividing the parity check matrix into rows that can be processed independently and in parallel. The row orthogonality property allows each row to be decoded without requiring complex inter-row dependencies, enabling modular implementation where multiple rows can be processed simultaneously, thereby reducing overall computational complexity while maintaining high transmission rates.
Data Source
AI summary
Certain aspects of the present disclosure generally relate to methods and apparatus for decoding low-density parity check (LDPC) codes, for example, using a parity check matrix having full row-orthogonality. An exemplary method for performing low-density parity-check (LDPC) decoding includes receiving soft bits associated to an LDPC codeword and performing LDPC decoding of the soft bits using a parity check matrix, wherein each row of the parity check matrix corresponds to a lifted parity check of a lifted LDPC code, at least two columns of the parity check matrix correspond to punctured variable nodes of the lifted LDPC code, and the parity check matrix has row orthogonality between each pair of consecutive rows that are below a row to which the at least two punctured variable nodes are both connected.