LDPC Parity Permutation for Additional Parity Transmission
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Solution Overview
Problem
Current signal transmission methods for digital broadcasting lack efficient mechanisms for improving decoding performance and supporting various receiving schemes, particularly in high-definition digital television and portable broadcasting, necessitating enhanced parity generation techniques.
Innovation Solution
A transmitter system that includes a Low Density Parity Check (LDPC) encoder, a parity permutator, a puncturer, and an additional parity generator, which interleaves and punctures parity bits using specific patterns to generate additional parity bits, improving decoding performance by optimizing the transmission of LDPC codewords through QPSK modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional LDPC encoding is used without additional parity generation, then the transmission process is simple, but decoding performance is insufficient for high-definition digital television and portable broadcasting
Solution Approach 1:
The patent applies preliminary action by generating additional parity bits from the LDPC codeword before transmission. The parity permutator and puncturer prepare extra redundancy information in advance, which is then transmitted alongside the main codeword. This pre-prepared additional parity information improves decoding performance at the receiver without requiring complex real-time processing during transmission.
Solution Approach 2:
The patent segments the parity bits into multiple groups and applies different permutation patterns to different segments. The parity bits are divided into first through fourth groups, with different groups subjected to different permutation operations. This segmentation allows the system to generate diverse parity information from the same source data, improving decoding reliability while maintaining a structured approach to complexity management.
2Reliability
If more parity bits are transmitted to improve decoding performance, then reliability increases, but transmission bandwidth is consumed
Solution Approach 1:
The patent changes parameters by applying different permutation patterns (first, second, third, and fourth patterns) to different parity bit groups. These parameter changes create diverse parity information from the same source data, effectively increasing the utility of transmitted bits. The puncturing operation also dynamically adjusts the amount of additional parity transmitted based on channel conditions and requirements, optimizing the balance between reliability and bandwidth consumption.
3Productivity
If parity bits are punctured to reduce transmission overhead, then bandwidth efficiency improves, but decoding performance may deteriorate
Solution Approach 1:
The patent applies preliminary action by pre-calculating multiple permutation patterns and preparing additional parity bits before puncturing. The system determines which parity bit groups to puncture based on predetermined patterns, ensuring that the most important parity information is preserved. This advance preparation allows the system to achieve both transmission efficiency and decoding performance by strategically selecting which parity bits to transmit and which to puncture.
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 to be transmitted in a current frame; a parity permutator configured to interleave the parity bits and group-wise interleave a plurality of parity bit groups configuring the interleaved parity bits based on a group-wise interleaving pattern including a first pattern and a second pattern to perform parity permutation; a puncturer configured to puncture at least some of the group-wise interleaved parity bit groups; and an additional parity generator configured to select at least some of the punctured parity bit groups to generate additional parity bits to be transmitted in a previous frame of the current frame, based on the first pattern and the second pattern.