LDPC Decoder Normalization for Lower Delay and Complexity
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Solution Overview
Problem
Prior art decoding algorithms for LDPC encoded signals, such as the Min-Sum algorithm, experience increased iterations and decoding delay, while algorithms like Normalized BP and Offset BP are dependent on factors that require precalculation and table-based corrections, making them inefficient and complex to implement.
Innovation Solution
A decoding apparatus that performs row and column processing in batches of one or more bits using a simplified update equation based on the Min-Sum algorithm, reducing iterations and calculation cost without relying on complex mathematical functions or precomputed factors, and dynamically adjusts factors based on modulation and code construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the Min-Sum algorithm is used for decoding LDPC coded signals, then the calculation cost is reduced and implementation is simplified, but the decoding performance degrades due to approximation of mathematical functions
Solution Approach 1:
The patent transforms the Min-Sum algorithm parameters by introducing a normalization factor that adjusts the approximated LLR values. This parameter change allows the system to maintain the computational simplicity of the Min-Sum algorithm while correcting the performance degradation through scaled probability information transmission between iterations
2Reliability
If iterative decoding is performed on all bits of the encoded signal in batches, then the decoding performance is improved, but the decoding delay increases with the number of iterations
Solution Approach 1:
The patent implements dynamic batch processing where the encoded signal is divided into multiple batches that are processed in parallel across different time slots. The normalization factor is updated dynamically based on the modulation scheme and code construction, allowing the system to adapt the processing speed and maintain performance while reducing overall decoding delay through concurrent batch operations
3Reliability
If Normalized BP or Offset BP algorithms are used to improve decoding performance, then the decoding capability is enhanced, but the device complexity increases due to precalculation of factors and table-based corrections
Solution Approach 1:
The patent extracts and removes the complex table-based correction mechanisms from the decoding process. Instead of using precomputed normalization tables, the system calculates the normalization factor directly from the modulation scheme parameters and code construction characteristics, eliminating the need for large lookup tables and reducing memory requirements while maintaining the performance benefits of normalized belief propagation
Data Source
AI summary
A decoding apparatus includes a row processing unit 5 and a column processing unit 6 for performing a calculation and an update of probability information with row processing and column processing according to a Min-Sum algorithm on a received signal which is low-density parity-check coded in batches of 1 bit or a predetermined number of bits, a decoded result judgment unit 8 for determining a decoded result from a hard decision of a posterior value, for performing a parity check on the decoded result, and for judging whether or not the decoded result is correct, and a control unit for controlling iteration of decoding processing by the row processing unit 5 and column processing unit 6 on the basis of the judgment result of the decoded result judgment unit 8.