LDPC Encoding Scheme Selection for Variable Coding Rates
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Solution Overview
Problem
Broadcast and communication systems using LDPC codes face challenges in maintaining high data reception quality due to variable block lengths and coding rates, especially in mobile and semi-fixed environments, where existing methods struggle to optimize error correction performance effectively.
Innovation Solution
The system employs a method to select between two coding methods based on different parity check matrices, allowing for variable coding rates and block lengths by using puncturing processing to adjust the number of bits transmitted, and corresponding decoding methods for error correction, ensuring high data reception quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single LDPC code with fixed block length and coding rate is used, then the system structure is simple, but the system cannot adapt to variable data amounts and different reception environments (mobile or semi-fixed)
Solution Approach 1:
The patent divides the LDPC code system into multiple code groups, each with different block lengths (e.g., 16200, 64800 bits) and coding rates. The transmitting device segments the information sequence according to the selected code group, and the receiving device processes different segments with corresponding decoding parameters. This segmentation enables the system to adapt to variable data amounts and reception environments while maintaining a structured approach to complexity management.
Solution Approach 2:
The patent implements dynamic selection of LDPC code parameters (block length, coding rate) based on reception environment conditions. The receiving device dynamically adjusts decoding parameters such as maximum iteration numbers and threshold values according to the selected code group and reception type (mobile or semi-fixed). This dynamic adaptation allows the system to optimize performance for different scenarios without requiring a completely different system structure.
2Productivity
If high coding rate is used to increase transmission efficiency, then productivity improves, but error correction performance deteriorates in mobile environments
Solution Approach 1:
The patent changes multiple parameters simultaneously to balance transmission efficiency and error correction performance. When mobile reception is detected, the system selects code groups with appropriate block lengths and coding rates, and adjusts decoding parameters including maximum iteration numbers and threshold values. For example, lower coding rates are selected for mobile environments to improve reliability, while higher coding rates can be used in semi-fixed environments for better productivity. This coordinated parameter adjustment resolves the contradiction between transmission efficiency and error correction performance.
3Adaptability or versatility
If multiple LDPC codes with different block lengths and coding rates are configured, then adaptability to variable data amounts improves, but the complexity of code selection and decoding parameter management increases
Solution Approach 1:
The patent creates a universal LDPC coding system that handles multiple code groups through a unified structure. The transmitting device uses a single encoding framework that can generate codes with different block lengths and coding rates by selecting appropriate code groups. The receiving device employs a universal decoding process that adapts to different code groups by adjusting parameters such as maximum iteration numbers and thresholds. This multi-functionality approach allows the system to handle variable data amounts without requiring separate processing paths for each code type, thereby managing complexity effectively.
4Adaptability or versatility
If puncturing processing is applied to achieve variable coding rates, then adaptability to different coding requirements improves, but the complexity of encoding and decoding processes increases
Solution Approach 1:
The patent applies puncturing processing during the encoding stage to pre-adjust the coding rate before transmission. The transmitting device performs puncturing on the LDPC codeword based on the selected code group and required coding rate, generating a punctured codeword that is then transmitted. The receiving device correspondsingly applies depuncturing processing before decoding. This preliminary action approach allows the system to achieve variable coding rates without complex real-time adjustments during decoding, as the coding rate adaptation is already prepared in advance during encoding.
Data Source
AI summary
One coding method of a plurality of coding methods including at least a first coding method and a second coding method is selected, an information sequence is encoded by using the selected coding method, and an encoded sequence obtained by performing predetermined processing on the information sequence is modulated and transmitted. The first coding method is a coding method having a first coding rate, for generating a first encoded sequence by performing puncturing processing on a generated first codeword by using a first parity check matrix. The second coding method is a coding method having a second coding rate, for generating a second encoded sequence by performing puncturing processing on a generated second codeword by using a second parity check matrix that is different from the first parity check matrix, the second coding rate after the puncturing process being different from the first coding rate.