Zigzag B-LDPC Encoding for Lower Complexity Signal Transmission
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Solution Overview
Problem
The existing LDPC codes in communications systems face performance degradation due to error floor phenomena caused by small-sized cycles, leading to increased encoding complexity and reduced error correction capability, especially in high-speed data transmission.
Innovation Solution
The implementation of a zigzag B-LDPC code using a structured interleaver to design a Concatenated ZigZag (CZZ) code with a parity check matrix, reducing encoding complexity and enhancing error correction by eliminating parity variable nodes with a weight of 1, thereby preventing performance degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional LDPC codes are used, then error correction capability is improved, but encoding complexity increases and small-sized cycles cause error floor phenomena
Solution Approach 1:
The LDPC code is segmented into multiple blocks, where each block can be independently encoded. This block-based structure reduces the overall encoding complexity by dividing the large sparse matrix into smaller manageable blocks, while maintaining the error correction capability through the distributed parity check structure across blocks.
Solution Approach 2:
Different blocks in the LDPC code are designed with locally optimized parity check matrices that eliminate small-sized cycles within each block. This local optimization ensures that each block contributes to error correction while avoiding the error floor phenomena caused by small cycles, thereby improving reliability without proportionally increasing complexity.
2Device complexity
If the number of small-sized cycles is increased, then encoding becomes simpler, but error correction capability deteriorates due to error floor phenomena
Solution Approach 1:
The harmful small-sized cycles are extracted and eliminated from the parity check matrix through careful design of the block structure. By removing these problematic cycles while maintaining the overall LDPC code structure, the error correction capability is preserved without requiring complex encoding procedures.
Solution Approach 2:
The parity check matrix employs an asymmetric block structure where different blocks have different configurations optimized to eliminate small cycles. This asymmetric design allows the code to achieve good error correction performance without the symmetry that would otherwise create small-sized cycles and error floor phenomena.
Data Source
AI summary
A method for transmitting a signal in a signal transmission apparatus of a communications system including receiving an information vector, and encoding the information vector according to a zigzag B-LDPC encoding scheme to generate a zigzag B-LDPC codeword, thereby advantageously reducing the encoding complexity together with enhanced error correction capability.