LDPC Channel Interleaving for Lower Error Rates in Fading Channels
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Solution Overview
Problem
Conventional communication systems lack a concrete channel interleaving/deinterleaving method tailored to the characteristics of Low Density Parity Check (LDPC) codes, which hinders the optimization of error rates and system performance.
Innovation Solution
A channel interleaving/deinterleaving apparatus and method that utilizes an encoder to generate LDPC codewords, a channel interleaver to interleave these codewords based on specific rules, and a decoder to recover information data bits, minimizing error rates by considering cycle size and node degree characteristics in the LDPC code structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional error-control schemes are used without LDPC-specific interleaving, then the system can operate with simpler processing, but error rates cannot be minimized and system performance is suboptimal
Solution Approach 1:
The patent applies parameter changes by modifying the interleaving strategy to be specifically adapted to LDPC code characteristics. The channel interleaver uses parameters such as cycle size and node degree from the LDPC parity check matrix to determine interleaving patterns, transforming a generic interleaving approach into one optimized for LDPC structures, thereby minimizing error rates while maintaining manageable complexity
Solution Approach 2:
The patent segments the LDPC codeword into multiple groups based on the cycle structure of the factor graph. By dividing the codeword according to the cyclic properties inherent in LDPC codes, the interleaving process can target specific segments with different error characteristics, improving overall reliability without requiring complex global interleaving schemes
2Reliability
If LDPC codes are used with optimized interleaving based on cycle size and node degree, then error rates are minimized and performance is enhanced, but the system requires more complex interleaving processing
Solution Approach 1:
The patent implements local quality by applying different interleaving strategies to different portions of the LDPC codeword based on local characteristics such as node degree and cycle size. Instead of using a uniform interleaving approach, the system adapts the interleaving pattern to match the local structure of the LDPC code, thereby achieving optimal error performance with targeted processing complexity
Solution Approach 2:
The patent performs preliminary action by pre-calculating and storing the interleaving pattern based on the LDPC parity check matrix characteristics before actual data transmission. The cycle structure and node degree information are analyzed in advance to generate the optimal interleaving sequence, which is then applied during transmission without requiring complex real-time computations, thus reducing operational complexity while maintaining high reliability
Data Source
AI summary
In a communication system, information data bits are encoded in a preset coding scheme when the information data bits are input, and a Low Density Parity Check (LDPC) codeword is generated. The LDPC codeword is interleaved according to a preset channel-interleaving rule. A channel-interleaved LDPC codeword is modulated in a preset modulation scheme and a modulation symbol is generated.