LDPC Transmitter Redundancy Mapping for Fading Channel Reception
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Solution Overview
Problem
Current digital broadcasting communication systems face challenges in enhancing reception performance due to errors caused by fading and thermal noise, particularly in wireless channels, where existing methods for error correction are inadequate.
Innovation Solution
A transmitter is designed to process and transmit signals using an incremental redundancy (IR) method, employing a low density parity check (LDPC) codeword with an encoder, interleaver, and constellation mapper, generating first and second parity bits based on specific parity check matrices to improve reception success rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If incremental redundancy (IR) method is used to transmit additional encoded data, then reception success rate is improved, but transmission time and system complexity increase
Solution Approach 1:
The parity check matrix is segmented into multiple submatrices, and the encoded data is divided into multiple segments transmitted at different times. This segmentation allows the receiver to process different portions of the code separately, reducing the complexity of handling the entire redundant code block at once while maintaining the error correction benefits of IR.
Solution Approach 2:
The transmitter pre-generates multiple segments of encoded data based on the parity check matrix structure before transmission. By preparing these segments in advance, the system can switch between different code rates without real-time computation overhead, reducing the operational complexity during actual transmission while maintaining high reception success rates.
2Reliability
If multiple parity submatrices are used to generate different parity bits, then error correction capability is improved, but encoding complexity increases
Solution Approach 1:
The parity check matrix is divided into multiple submatrices, each responsible for generating specific parity bits. This segmentation allows the encoder to process different parity bits independently through separate submatrices, reducing the computational complexity of handling the entire parity check matrix at once while maintaining comprehensive error correction capability.
Solution Approach 2:
Different submatrices are designed with specific structures optimized for their particular functions. By assigning different local qualities (structural characteristics) to different submatrices, the system achieves high overall error correction capability while keeping individual encoding operations relatively simple and manageable.
3Measurement precision
If code rate is reduced to improve reception performance, then decoding accuracy is improved, but transmission efficiency decreases
Solution Approach 1:
The system dynamically adjusts the code rate by selectively transmitting different segments of encoded data based on channel conditions and reception requirements. This dynamic adaptation allows the system to achieve high decoding accuracy when needed while maintaining transmission efficiency through flexible code rate variation, resolving the contradiction between accuracy and efficiency.
Solution Approach 2:
The system changes the code rate parameter by transmitting additional parity bits from different submatrices when reception difficulties are detected. This parameter change enables the receiver to improve decoding accuracy by incorporating more redundant information without permanently reducing transmission efficiency, as the higher code rate is only applied selectively when needed.
Data Source
AI summary
A transmitter is provided, which includes: an encoder configured to generate a low density parity check (LDPC) codeword comprising information word bits, first parity bits and second parity bits based on a parity check matrix; an interleaver configured to interleave the LDPC codeword; and a constellation mapper configured to map the interleaved LDPC codeword on constellation points, wherein the first parity bits are generated based on one of parity submatrices constituting the parity check matrix and the second parity bits are generated based on another of the parity submatrices constituting the parity check matrix.