LDPC Transmitter Parity Puncturing With Additional Parity Bits
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Solution Overview
Problem
Current signal transmission methods in digital broadcasting lack efficiency in providing improved performance and diversity gain, particularly in high-definition digital television and portable broadcasting, due to limitations in existing parity generation and transmission schemes.
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 generates additional parity bits based on the number of outer encoded bits and remaining parity bits, to enhance coding and diversity gains.
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) and stores them for later use. When puncturing removes parity bits to improve bandwidth efficiency, these pre-generated additional parity bits are available to compensate for the lost error correction capability, thus resolving the contradiction between bandwidth efficiency and reliability
Solution Approach 2:
The patent dynamically adjusts the number of additional parity bits based on the puncturing pattern and channel conditions. By changing the parameter of additional parity bit quantity according to the degree of puncturing applied, the system maintains optimal error correction capability while achieving desired bandwidth efficiency
2Reliability
If additional parity bits are generated to improve error correction capability, then reliability is improved, but transmission overhead increases
Solution Approach 1:
The patent generates more parity bits than the minimum required for basic error correction, creating a pool of additional parity bits. The receiver then selectively uses only the necessary portion of these additional parity bits based on actual channel conditions and puncturing patterns, achieving sufficient reliability without always incurring maximum overhead
Solution Approach 2:
The system dynamically determines the number of additional parity bits to transmit based on puncturing patterns and channel quality. This dynamic adjustment allows the system to optimize the balance between reliability improvement and transmission overhead, transmitting more additional parity bits only when needed
3Reliability
If repetition is applied to enhance diversity gain, then reliability is improved, but bandwidth efficiency deteriorates
Solution Approach 1:
The patent combines repetition coding with LDPC encoding by integrating repeated bits into the LDPC codeword structure. This merging allows the system to achieve diversity gain from repetition while maintaining the efficient error correction capabilities of LDPC, thereby improving reliability without as severe a penalty to bandwidth efficiency as traditional repetition coding
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.