LDPC Channel Encoding with Group Shortening for Flexible Code Rates
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Solution Overview
Problem
Existing LDPC code systems require high memory capacity to support various codeword lengths and code rates, leading to reduced system efficiency due to the need for multiple parity check matrixes, and there is a need for methods to efficiently generate and decode LDPC codes with different lengths and rates without generating new matrices.
Innovation Solution
The method involves shortening or puncturing a given parity check matrix in a communication system using LDPC codes, determining a shortening pattern based on the number of shortened and punctured bits, and applying this pattern to group information bits to achieve different codeword lengths and code rates, optimizing performance by considering specific structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple parity check matrixes are used to support various codeword lengths and code rates, then the system can achieve high adaptability, but the memory capacity requirement increases significantly
Solution Approach 1:
The patent applies universality by designing a single parity check matrix that can serve multiple functions for different codeword lengths and code rates. The base matrix is configured with a structure that allows flexible extraction of sub-matrices through shortening and puncturing techniques, enabling one matrix to replace multiple specialized matrices while maintaining support for various communication requirements.
Solution Approach 2:
The patent employs segmentation by dividing the base parity check matrix into multiple sub-matrices through systematic shortening and puncturing operations. The base matrix is segmented into information bit portions and parity bit portions, with further segmentation achieved by selectively removing columns to generate sub-matrices for different code rates and lengths, thereby reducing the need to store multiple complete matrices.
2Quantity of substance
If a single parity check matrix is used to support various codeword lengths and code rates, then memory requirements are reduced, but the complexity of generating and decoding different codes increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring the base parity check matrix with a specific structure that facilitates easy generation of sub-matrices for different code rates and lengths. The base matrix is designed in advance with patterns that allow systematic shortening and puncturing, so that when different codes are needed, the appropriate sub-matrices can be quickly extracted without complex real-time processing.
Solution Approach 2:
The patent utilizes parameter changes by modifying the effective dimensions and structure of the parity check matrix through controlled shortening and puncturing operations. By changing parameters such as the number of information bits, the number of parity bits, and the selection of columns to retain or remove, the system generates different code rates and lengths from a single base matrix, managing complexity through parameterization rather than structural redesign.
3Reliability
If multiple parity check matrixes are stored to support different code rates, then decoding performance is optimized for each specific rate, but system efficiency decreases due to increased memory usage
Solution Approach 1:
The patent applies universality by designing a single parity check matrix that can serve multiple functions for different codeword lengths and code rates. The base matrix is configured with a structure that allows flexible extraction of sub-matrices through shortening and puncturing techniques, enabling one matrix to replace multiple specialized matrices while maintaining support for various communication requirements.
Solution Approach 2:
The patent employs local quality by optimizing specific portions of the base matrix for different decoding scenarios. Different columns and rows of the base matrix are designed with local structural characteristics that favor particular code rates or lengths, allowing the system to extract sub-matrices with optimized local properties for specific applications while maintaining overall system efficiency through a single unified structure.
Data Source
AI summary
A method is provided for channel encoding in a communication system using a Low-Density Parity Check (LDPC) code. The method includes grouping information bits into a plurality of groups, determining an order of the plurality of groups to be shortened, according to a code rate, determining a length of information bits to be obtained by shortening the plurality of groups, shortening the plurality of groups on a group basis in the determined order, based on the determined length of the information bits, and LDPC-encoding shortened information bits.