LDPC Transmitter Parity Scheduling for Punctured Broadcast Frames
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Solution Overview
Problem
Current signal transmission methods for digital broadcasting lack an efficient way to provide improved performance and support for various receiving schemes, particularly in high definition digital television and portable broadcasting, necessitating a more effective method for generating additional parity bits to enhance coding gain and diversity.
Innovation Solution
A transmitter system that includes a Low Density Parity Check (LDPC) encoder, a repeater, and an additional parity generator, which encodes input bits to generate LDPC codewords, punctures parity bits, and selects additional parity bits based on the number of outer encoded bits and remaining parity bits, with the option to repeat bits within the codeword for transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If puncturing is applied to reduce transmission overhead, then bandwidth efficiency is improved, but error correction capability deteriorates
Solution Approach 1:
The patent generates additional parity bits in advance (before transmission) based on the puncturing pattern. These additional parity bits are prepared beforehand to compensate for the loss of original parity bits, ensuring that error correction capability is maintained despite the puncturing that improves bandwidth efficiency.
Solution Approach 2:
The patent changes the parameter of parity bit generation by creating additional parity bits with a different structure or distribution than the original parity bits. This allows the system to adapt to the punctured transmission format while maintaining the necessary error correction capability through modified parity check relationships.
2Reliability
If additional parity bits are generated to improve error correction, then reliability is improved, but transmission overhead increases
Solution Approach 1:
The patent generates additional parity bits selectively rather than uniformly for all transmissions. The number and distribution of additional parity bits are adjusted based on the specific puncturing pattern and channel conditions, providing just enough error correction capability without excessive overhead in situations where full protection is not needed.
3Productivity
If code rate is increased to improve data throughput, then productivity is improved, but error correction capability deteriorates
Solution Approach 1:
The patent prepares additional parity bits in advance based on the higher code rate and puncturing pattern. This preliminary generation of compensatory parity information allows the system to maintain adequate error correction capability even when operating at higher code rates that would otherwise reduce redundancy and error correction performance.
Data Source
AI summary
A transmitter is provided. The transmitter includes: a Low Density Parity Check (LDPC) encoder which encodes input bits including outer encoded bits to generate an LDPC codeword including the input bits and parity bits to be transmitted to a receiver in a current frame; a puncturer which punctures a part of the parity bits which is not transmitted in the current frame; and an additional parity generator which selects at least a part of the parity bits to generate additional parity bits transmitted to the receiver in a previous frame of the current frame, wherein a number of the additional parity bits is determined based on a number of the outer encoded bits and a number of the parity bits left after the puncturing.