LDPC Additional Parity Generation from Punctured Broadcast Codewords
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Solution Overview
Problem
Current signal transmission methods for digital broadcasting lack efficient mechanisms to improve decoding performance and adapt to varying signal reception schemes, particularly in high-definition digital television and portable broadcasting scenarios.
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 uses interleaving patterns to generate additional parity bits by puncturing and rearranging LDPC codewords, improving decoding performance through optimized parity bit selection and transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional LDPC encoding is used without additional parity generation, then transmission bandwidth is saved, but decoding performance and reliability are insufficient
Solution Approach 1:
The patent performs preliminary actions by generating additional parity bits from punctured parity bits before transmission. The parity permutator rearranges parity bits and the additional parity generator creates redundant parity information that will be useful for future decoding operations, improving reliability without requiring immediate additional bandwidth.
Solution Approach 2:
The patent discards certain parity bits through puncturing to save bandwidth, then recovers decoding performance by generating additional parity bits from the remaining punctured parity bits. This allows the system to temporarily discard information that can be reconstructed later using the additional parity, resolving the contradiction between bandwidth savings and decoding reliability.
2Adaptability or versatility
If fixed parity bit transmission is used, then system complexity is reduced, but adaptability to varying signal reception schemes is limited
Solution Approach 1:
The patent introduces dynamic elements by making the additional parity generation adaptive to different reception schemes. The system can adjust which parity bits are punctured and how additional parity is generated based on the specific reception requirements, providing versatility while managing complexity through structured adaptation rather than complete flexibility.
Solution Approach 2:
The patent changes parameters such as the number of punctured parity bits and the pattern of additional parity generation to adapt to different signal reception schemes. By varying these parameters based on reception requirements, the system achieves adaptability while maintaining a relatively simple base structure that doesn't require complete redesign for each scheme.
3Productivity
If all parity bits are transmitted without puncturing, then decoding reliability is maximized, but transmission efficiency decreases
Solution Approach 1:
The patent extracts specific parity bits for puncturing based on predetermined patterns, removing only the necessary minimum number of parity bits to achieve the desired code rate. This selective extraction maintains transmission efficiency while preserving enough parity information to generate additional parity bits, thereby maintaining decoding reliability without transmitting all original parity bits.
Solution Approach 2:
The additional parity bits act as an intermediary that bridges the gap between punctured parity bits and the original full parity set. By generating these intermediate additional parity bits from the punctured ones, the system recovers the necessary redundancy for reliable decoding while having transmitted fewer original parity bits, thus improving transmission efficiency without sacrificing reliability.
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 perform parity-permutation by interleaving the parity bits and group-wise interleaving a plurality of bit groups configuring the interleaved parity bits based on a group-wise interleaving pattern including a first pattern and a second pattern; a puncturer configured to puncture some of the parity-permutated parity bits; and an additional parity generator configured to select at least some of the punctured parity bits 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, wherein the first pattern determines parity bits to remain after the puncturing and then to be transmitted in the current frame.