LDPC Bit Interleaver for Burst Error Distribution in 16-Symbol Mapping
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Solution Overview
Problem
Bit-Interleaved Coded Modulation (BICM) systems suffer from rapid performance degradation due to burst errors in digital broadcast channels, necessitating an optimized bit interleaver design for modulation order and error correction code parameters.
Innovation Solution
A bit interleaver is designed for an LDPC coder with a length of 16200 and a code rate of 4/15, using a processor to generate an interleaved codeword on a bit group basis, with a specific permutation order for effective error distribution, and a modulator performing 16-symbol mapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional bit interleaver is used in BICM systems, then the system structure remains simple, but burst errors in the channel cause rapid performance degradation
Solution Approach 1:
The bit interleaver divides the codeword into multiple bit groups and applies different interleaving patterns to different segments. This segmentation allows the system to handle burst errors more effectively by distributing them across different code blocks, thereby improving reliability without requiring a complete redesign of the entire interleaving structure.
Solution Approach 2:
The patent implements different interleaving strategies for different parts of the codeword based on their specific requirements. By applying localized optimization to specific bit groups rather than using a uniform approach, the system achieves better error distribution performance while maintaining reasonable overall complexity.
2Reliability
If the bit interleaver is optimized for specific modulation order and code parameters, then performance improves, but the adaptability to different configurations decreases
Solution Approach 1:
The bit interleaver design incorporates configurable parameters such as bit group size, interleaving depth, and permutation patterns that can be adjusted according to different modulation orders and code rates. This allows the same basic structure to be optimized for specific configurations while maintaining the ability to adapt to other configurations through parameter modification rather than structural redesign.
3Reliability
If burst errors are not distributed, then the system structure remains simple, but error correction capability deteriorates rapidly
Solution Approach 1:
The bit interleaver performs error distribution preparation before the actual error correction decoding process. By pre-distributing burst errors across different code blocks through interleaving, the system ensures that the subsequent error correction decoder receives a more uniformly distributed error pattern, thereby improving overall error correction capability without adding complexity to the decoder itself.
Data Source
AI summary
A bit interleaver, a bit-interleaved coded modulation (BICM) device and a bit interleaving method are disclosed herein. The bit interleaver includes a first memory, a processor, and a second memory. The first memory stores a low-density parity check (LDPC) codeword having a length of 16200 and a code rate of 4/15. The processor generates an interleaved codeword by interleaving the LDPC codeword on a bit group basis. The size of the bit group corresponds to a parallel factor of the LDPC codeword. The second memory provides the interleaved codeword to a modulator for 16-symbol mapping.