LDPC Transmitter Parity Puncturing for Coding Gain and Diversity
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Solution Overview
Problem
Current signal transmission methods in digital broadcasting lack efficiency in providing improved performance and diversity gains, particularly in high-definition digital TV and portable broadcasting, due to limitations in existing parity generation and coding schemes.
Innovation Solution
A transmitter system utilizing a Low Density Parity Check (LDPC) encoder, repeater, and additional parity generator to generate and transmit additional parity bits, which are determined based on the number of outer encoded bits and remaining parity bits after puncturing, to enhance coding gain and diversity in signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional LDPC encoding is used without additional parity bits, then the transmission structure is simple, but coding gain and diversity performance are insufficient
Solution Approach 1:
The parity bits are segmented into two categories: original parity bits generated by the LDPC encoder and additional parity bits generated by the additional parity generator. This segmentation allows the system to maintain the original simple LDPC encoding structure while adding enhanced error correction capability through the additional parity bits, thereby improving coding gain and diversity performance without fundamentally complicating the core encoding mechanism.
Solution Approach 2:
The additional parity bits are generated in advance during the encoding process, before transmission occurs. The additional parity generator receives the outer encoded bits and generates additional parity bits that are then combined with the original parity bits to form the complete transmitted signal. This preliminary generation of additional parity information enables improved reliability without requiring complex real-time processing during transmission.
2Productivity
If all parity bits are transmitted in the current frame, then complete error correction information is provided, but puncturing cannot be applied to optimize transmission
Solution Approach 1:
The system dynamically adjusts the number of additional parity bits generated based on the number of punctured parity bits. When puncturing is applied to optimize transmission efficiency, the additional parity generator compensates by generating an equivalent number of additional parity bits. This parameter adjustment ensures that the total error correction information remains sufficient while allowing the puncturing operation to improve transmission efficiency by removing redundant or less critical parity bits from the current frame.
3Reliability
If additional parity bits are generated for previous frame transmission, then diversity gain is improved, but the number of bits to process increases
Solution Approach 1:
The system generates only the necessary number of additional parity bits equal to the number of punctured parity bits, rather than generating excessive redundancy. This partial action approach provides sufficient diversity gain for improved reliability while avoiding the unnecessary processing complexity that would result from generating more additional parity bits than needed. The additional parity generator processes only the outer encoded bits to produce the required additional parity information.
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.