LDPC Transmitter Repetition and Puncturing for Better Decoding
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Solution Overview
Problem
Current signal transmission methods for digital broadcasting services, such as high definition digital television and portable broadcasting devices, face limitations in providing improved performance and efficiency in signal transmission and reception, particularly in terms of decoding and error correction.
Innovation Solution
A transmitter system utilizing a Low Density Parity Check (LDPC) encoder, repeater, and puncturer to encode and repeat input bits, adding selected parity bits and puncturing others to enhance decoding performance, specifically by calculating the number of bits to be selected and added based on the number of outer encoded bits and padding zero bits, and performing repetition and puncturing operations to improve signal reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bits are repeated to improve decoding performance, then reliability is improved, but device complexity increases
Solution Approach 1:
The transmitter is divided into three functional modules: an LDPC encoder for encoding input bits, a repeater for selecting and repeating specific bits, and a puncturer for removing selected parity bits. This segmentation allows each module to perform a specific function, improving decoding performance through bit repetition while managing complexity through modular design.
Solution Approach 2:
Instead of repeating all bits in the LDPC codeword, the repeater selectively repeats only certain bits (such as parity bits or specific positions) based on the repetition rate. This partial action approach improves decoding performance for critical bits without unnecessarily increasing the overall transmission length and complexity.
2Reliability
If the number of repeated bits is increased to improve signal reliability, then decoding performance is improved, but transmission time increases
Solution Approach 1:
The repeater applies partial repetition by selecting only specific bits (e.g., parity bits or bits at certain positions) to be repeated, rather than repeating the entire codeword. The repetition rate parameter controls the degree of repetition, allowing optimization between reliability improvement and transmission time increase based on channel conditions.
Solution Approach 2:
The system uses a configurable repetition rate parameter to control the number of bits to be repeated. This parameter can be adjusted to balance between improving signal reliability (higher repetition rate) and minimizing transmission time (lower repetition rate), allowing adaptive optimization based on channel quality and service requirements.
3Productivity
If parity bits are punctured to reduce transmission overhead, then productivity is improved, but reliability deteriorates
Solution Approach 1:
The puncturer applies partial puncturing by removing only selected parity bits rather than all parity bits. This selective puncturing reduces transmission overhead and improves productivity while maintaining sufficient error correction capability through the remaining parity bits and the repetition of critical bits performed by the repeater.
Solution Approach 2:
The repeater performs bit repetition before puncturing, creating redundant copies of critical bits. This beforehand cushioning ensures that even after some parity bits are punctured to improve productivity, the repeated bits provide sufficient reliability for error correction and decoding.
Data Source
AI summary
A transmitter is provided. The transmitter includes: a low density parity check (LDPC) encoder configured to encode input bits to generate an LDPC codeword including the input bits and parity bits; a repeater configured to select at least a part of bits constituting the LDPC codeword and add the selected bits after the input bits; and a puncturer configured to puncture at least a part of the parity bits.