Polar Code Soft Decoding Using LLR Probability Conversion
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Solution Overview
Problem
Conventional polar code decoders in nonvolatile memory systems, such as flash memories, do not effectively utilize log likelihood ratio values for direct input, leading to inefficiencies in decoding processes.
Innovation Solution
Implementing a soft decoding method that converts log likelihood ratio values into transition error probabilities, allowing for low complexity and flexible list decoding techniques, which modify hard bits and utilize channel side information for improved decoding performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional polar decoders are used with log likelihood ratio values, then the decoding structure is simple, but the decoding performance is insufficient
Solution Approach 1:
The patent introduces an intermediary conversion process that transforms log likelihood ratio values into transition error probabilities before feeding them to the polar decoder. This mediator (probability conversion module) bridges the gap between the simple conventional decoder structure and the need for improved decoding performance by enabling soft decoding capabilities.
Solution Approach 2:
The invention changes the parameter representation from log likelihood ratios to transition error probabilities. This parameter transformation allows the decoder to utilize soft information more effectively, improving reliability while maintaining a relatively simple structural implementation through the use of standard polar decoding algorithms with modified input parameters.
2Reliability
If log likelihood ratio values are directly input to conventional polar decoders, then the processing is straightforward, but the error correction capability is limited
Solution Approach 1:
The patent applies preliminary action by converting log likelihood ratio values into transition error probabilities before the main decoding operation. This pre-processing step prepares the input data in a format that enables better error correction capability while keeping the overall process systematic and manageable.
3Adaptability or versatility
If soft list decoding techniques are implemented with probability conversion, then decoding flexibility improves, but computational complexity increases
Solution Approach 1:
The patent segments the decoding process into distinct functional modules: probability conversion module, hard slicing module, and soft list decoding module. This segmentation allows each module to perform its specific function with optimized complexity, providing decoding flexibility through modular design while managing overall computational complexity through clear separation of concerns.
Data Source
AI summary
An apparatus having a circuit and an interface to a nonvolatile memory is disclosed. The circuit is configured to (i) read a plurality of bits in a read channel of the nonvolatile memory. The bits are encoded with a polar code. The circuit is also configured to (ii) generate a plurality of probabilities based on a plurality of log likelihood ratio values of the read channel and (iii) decode the bits based on the probabilities.