LDPC Parity-Check Matrix Scaling for Variable Codeword Lengths
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Solution Overview
Problem
Existing LDPC code technologies face challenges in supporting various input lengths and coding rates, particularly in mobile communication systems, due to limitations in designing parity-check matrices that can efficiently handle variable lengths and rates.
Innovation Solution
The development of a method and apparatus for low-density parity-check (LDPC) encoding/decoding that utilizes a designed parity-check matrix to support various codeword lengths and coding rates, employing a changed lifting process to optimize the parity-check matrix design, allowing for efficient encoding and decoding of variable-length and variable-rate LDPC codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed parity-check matrix design is used for LDPC coding, then the encoding/decoding process is simple, but the system cannot support various input lengths and coding rates
Solution Approach 1:
The patent applies dynamics by making the lifting value Z variable rather than fixed. The lifting value Z determines the size of circulant permutation matrices in the parity-check matrix, and by allowing Z to change, the system can support various codeword lengths and coding rates. This dynamic adjustment enables the LDPC code to adapt to different transmission requirements while maintaining a systematic design approach based on circulant matrices.
Solution Approach 2:
The patent changes the parameter Z (lifting value) to support various input lengths and coding rates. By modifying this key parameter in the parity-check matrix construction, the system can generate different code lengths and rates from a unified design framework. This parameter change approach allows flexible adaptation without redesigning the entire parity-check matrix structure.
2Adaptability or versatility
If the lifting value Z is fixed in the parity-check matrix design, then the matrix structure is simple, but various codeword lengths cannot be supported
Solution Approach 1:
The patent makes the lifting value Z dynamic rather than fixed. By allowing Z to vary, the circulant permutation matrices in the parity-check matrix can change size, enabling support for various codeword lengths. This dynamic approach maintains structural regularity while achieving flexibility in code length adaptation.
Solution Approach 2:
The patent creates a universal parity-check matrix design that can serve multiple functions by changing the lifting value Z. A single design framework based on circulant matrices with variable Z can generate LDPC codes with different lengths and rates, making the system multi-functional without requiring separate designs for each code configuration.
3Adaptability or versatility
If LDPC codes are designed to support variable lengths and rates, then communication flexibility improves, but error correction performance may deteriorate
Solution Approach 1:
The patent carefully manages parameter changes by modifying only the lifting value Z while maintaining the circulant matrix structure. This controlled parameter change allows variable length and rate support while preserving the mathematical properties that ensure good error correction performance. The systematic approach to parameter modification prevents performance deterioration.
Solution Approach 2:
The patent segments the parity-check matrix into circulant permutation matrices and zero matrices in a systematic pattern. This segmentation approach allows flexible adjustment of code length and rate by changing Z, while the regular structure maintains good error correction properties. The segmented design enables independent optimization of different matrix blocks.
Data Source
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AI summary
The present invention related to a 5G or pre-5G communication system to be provided to support a higher data transmission rate since 4G communication systems like LTE. The present invention relates to a method and an apparatus for encoding a channel in a communication or broadcasting system supporting parity-check matrices having various sizes are provided. The method for encoding a channel includes determining a block size of the parity-check matrix; reading a sequence for generating the parity-check matrix, and transforming the sequence by applying a previously defined operation to the sequence based on the determined block size.