Quasi-Cyclic LDPC Interleaving via Matrix Block Permutation
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Solution Overview
Problem
Conventional cell interleaving methods often fail to sufficiently improve reception performance in communication systems due to limitations in spreading burst errors across codewords.
Innovation Solution
A transmission method utilizing a quasi-cyclic low-density parity-check coding scheme with bit and constellation block permutations, where bits are divided into sections and permuted to create constellation blocks that are written row-wise into a matrix and read column-wise, ensuring even distribution of errors across the codeword.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cell interleaving is applied to spread burst errors, then error distribution is improved, but reception performance is insufficient
Solution Approach 1:
The codeword is divided into multiple sections, with each section containing multiple quasi-cyclic blocks. This segmentation allows for more granular control of error distribution and enables the system to achieve better reception performance by processing smaller units independently, thereby resolving the contradiction between reliability improvement and structural complexity
Solution Approach 2:
The patent introduces a two-dimensional interleaving structure by organizing constellation blocks into a matrix with R rows and C columns. This dimensional transformation enables errors to be spread across both row and column dimensions, achieving superior error distribution and reception performance without proportionally increasing system complexity
2Reliability
If bits are divided into fewer sections, then processing complexity is reduced, but error distribution across codeword is insufficient
Solution Approach 1:
The patent optimizes the parameters of section division by establishing specific relationships between the number of sections M, the number of quasi-cyclic blocks per section, and the constellation block matrix dimensions. By carefully selecting these parameters, the system achieves effective error distribution while controlling processing complexity through mathematical relationships rather than arbitrary divisions
3Reliability
If constellation blocks are arranged in simple sequence, then processing is simpler, but burst error spreading is insufficient
Solution Approach 1:
The patent transforms the simple sequential arrangement into a two-dimensional matrix arrangement where constellation blocks are written row-wise and read column-wise (or vice versa). This dimensional transformation automatically achieves burst error spreading without requiring complex permutation algorithms, as the matrix structure itself provides the necessary error distribution
Solution Approach 2:
The constellation blocks are pre-arranged in a specific matrix pattern before transmission. This preliminary organization ensures that when burst errors occur during transmission, they naturally affect blocks that are spatially separated in the original codeword structure, achieving error spreading without real-time complex processing
Data Source
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AI summary
In order to transmit a codeword that is generated based on a quasi-cyclic low-density parity-check coding scheme and consists of N cyclic blocks each consisting of Q bits, a bit permutation is applied to the bits of the codeword, a plurality of constellation blocks each consisting of G×M bits are generated, and a block permutation is applied to the constellation blocks. The bit permutation is adopted for each of N/M sections each consisting M cyclic blocks such that the constellation blocks each consist of G×M bits from M distinct cyclic blocks of the associated section. The block permutation is equivalent to writing the constellation blocks into a matrix with R rows and (Q/(k×G)) columns and reading out the constellation blocks column by column from the matrix, where R is k×(N/M), and k is a positive integer.