LDPC Transmitter Puncturing for Decoding Reliability and Bandwidth
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Solution Overview
Problem
Current signal transmitters and receivers for digital broadcasting face challenges in providing improved performance and robustness, particularly in high-definition digital TV and portable broadcasting, due to limitations in parity bit management and puncturing methods for LDPC codes.
Innovation Solution
A transmitter system that includes an LDPC encoder and a puncturer, which calculates and punctures parity bits based on specific ratios and minimum values to optimize the number of parity bits transmitted, improving decoding performance and adapting to different robustness levels without altering the modulation order.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all parity bits are transmitted in LDPC coding, then decoding reliability is improved, but transmission efficiency and bandwidth utilization deteriorate
Solution Approach 1:
The patent extracts and removes a portion of the parity bits from the LDPC codeword for transmission. The puncturer selectively removes parity bits based on predetermined patterns, transmitting only a subset of parity bits while maintaining sufficient decoding reliability through careful selection of which parity bits to retain and which to puncture.
Solution Approach 2:
The patent changes the parameter of parity bit transmission by introducing a puncturing rate that controls the proportion of parity bits transmitted. Different puncturing patterns and rates can be selected based on channel conditions and service requirements, allowing dynamic adjustment between reliability and transmission efficiency.
2Reliability
If more parity bits are transmitted, then error correction capability is improved, but bandwidth utilization and transmission speed deteriorate
Solution Approach 1:
The patent extracts only the necessary portion of parity bits for transmission by applying puncturing patterns that remove redundant parity bits. This extraction process maintains the essential error correction capability while reducing the total quantity of transmitted bits, thereby improving bandwidth utilization.
Solution Approach 2:
The patent applies partial action by transmitting only a subset of parity bits rather than all parity bits. The puncturing pattern is designed to retain sufficient parity bits for acceptable error correction performance while removing excess parity bits that would consume valuable bandwidth without providing proportional benefit.
3Ease of manufacture
If fixed puncturing scheme is used, then implementation simplicity is maintained, but adaptability to different service requirements deteriorates
Solution Approach 1:
The patent introduces dynamic puncturing schemes where the puncturing pattern and rate can be changed based on service requirements, channel conditions, and traffic types. Multiple puncturing patterns are defined that can be selected dynamically, allowing the system to adapt between different service modes (e.g., robust mode for poor channels, efficient mode for good channels) while maintaining relatively simple implementation through pre-defined patterns.
Solution Approach 2:
The patent creates a universal puncturing framework that can handle multiple service requirements and transmission scenarios through a set of standardized puncturing patterns. The same basic puncturing mechanism serves multiple functions by selecting different patterns based on service type, making the system versatile without requiring complex custom implementations for each scenario.
Data Source
AI summary
A transmitter is provided. The transmitter includes: a Low Density Parity Check (LDPC) encoder configured to encode outer-encoded bits to generate an LDPC codeword including LDPC information bits and parity bits; a puncturer configured to puncture some of the parity bits included in the LDPC codeword; and a mapper configured to map the LDPC codeword except the punctured parity bits to symbols for transmission to a receiver, wherein the puncturer calculates a number of parity bits to be punctured among the parity bits included in the LDPC codeword based on a number of the outer-encoded bits, a number of the LDPC information bits, and a minimum number of parity bits to be punctured among the parity bits included in the LDPC codeword.