QC-LDPC Bit Interleaver Folding Across Cyclic Blocks
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Solution Overview
Problem
Existing bit-interleaved coding and modulation systems with quasi-cyclic low-density parity-check codes face inefficiencies in interleaving, particularly when the number of cyclic blocks is not a multiple of the bit interleaver's columns, leading to impaired parallelism and increased latency, especially in iterative decoding processes.
Innovation Solution
A bit interleaving method that divides codewords into folding sections, applying a bit permutation process to map M bits from each constellation word across multiple cyclic blocks, ensuring all bits in a folding section are mapped to only Q/F constellation words, thereby optimizing interleaving efficiency and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional bit interleaving is applied to QC-LDPC codewords, then the interleaving process can be performed, but parallelism is impaired and latency increases when the number of cyclic blocks is not a multiple of the interleaver columns
Solution Approach 1:
The patent divides the codeword into multiple folding sections, where each folding section contains a specific number of cyclic blocks. This segmentation allows the interleaving process to be organized into manageable units that can be processed in parallel, resolving the contradiction by structuring the data to enable parallelism while maintaining complete processing of all cyclic blocks regardless of whether N is a multiple of the number of columns
Solution Approach 2:
The patent introduces a folding factor F that creates an additional dimension in the interleaving structure. By organizing bits into folding sections and using the folding factor to determine how many cyclic blocks are grouped together, the system transforms the traditional single-dimension interleaving into a multi-dimensional structure that enables parallel processing while handling any number of cyclic blocks
2Adaptability or versatility
If the number of cyclic blocks N is not a multiple of the number of columns in the bit interleaver, then all cyclic blocks can be processed, but parallelism is impaired
Solution Approach 1:
The patent makes the interleaver structure dynamic by introducing the folding factor F, which allows the number of folding sections and the composition of each section to adapt based on the actual number of cyclic blocks N. This dynamic structure enables the system to maintain parallelism for any value of N by adjusting how cyclic blocks are grouped into folding sections, rather than requiring a fixed structure that only works when N is a multiple of the number of columns
Data Source
AI summary
A bit interleaving method involves applying a bit permutation process to a QC-LDPC codeword made up of N cyclic blocks each including Q bits, and dividing the codeword after the permutation process into a plurality of constellation words each including M bits, the codeword being divided into F×N/M folding sections, each of the constellation words being associated with one of the F×N/M folding sections, and the bit permutation process being applied such that each of the constellation words includes F bits from each of M/F different cyclic blocks in a given folding section associated with a given constellation word.