LDPC Parity Interleaving for Bandwidth-Efficient Decoding
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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 conditions, 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, and an additional parity generator, which uses interleaving patterns to generate additional parity bits by puncturing and rearranging LDPC parity bits, improving decoding performance through group-wise interleaving and puncturing strategies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LDPC encoding is performed with standard parity bits only, then transmission bandwidth is conserved, but decoding performance is insufficient for high-definition digital television and portable broadcasting
Solution Approach 1:
The parity bits are segmented into multiple groups (first parity bit group, second parity bit group, third parity bit group) which are then selectively transmitted in different frames. This segmentation allows the system to provide additional parity information without transmitting all parity bits continuously, thus improving decoding performance while managing bandwidth usage efficiently
Solution Approach 2:
The transmitter pre-generates multiple sets of parity bits through LDPC encoding and prepares them in advance for selective transmission. The parity permutator and puncturer are configured beforehand to select and arrange the appropriate parity bits for current and previous frames, enabling improved decoding performance when needed
2Reliability
If all parity bits are transmitted in every frame, then decoding performance is maximized, but transmission efficiency and bandwidth utilization deteriorate
Solution Approach 1:
The system transmits different parity bit groups in an alternating periodic manner across frames. For example, even frames may transmit one set of parity bits while odd frames transmit another set, creating a periodic transmission pattern that improves decoding performance over time without requiring all parity bits to be transmitted in every frame
Solution Approach 2:
Different parity bit groups are transmitted selectively based on specific frame requirements and channel conditions. The system applies different transmission qualities to different parity groups - some are transmitted in all frames while others are transmitted only in specific frames, optimizing both decoding performance and transmission efficiency
3Quantity of substance
If puncturing is applied to reduce transmitted parity bits, then bandwidth is conserved, but decoding reliability may be compromised
Solution Approach 1:
The puncturer selectively discards (punctures) certain parity bits from transmission in the current frame, but the corresponding parity information is recovered in subsequent frames through the periodic transmission of different parity bit groups. This allows bandwidth conservation in individual frames while maintaining overall decoding reliability across multiple frames
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 by group-wise interleaving a plurality of bit groups configuring the parity bits based on a group-wise interleaving pattern comprising 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.