Turbo Product Polar Coding with BCH Hard-Decision Cleaning
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Solution Overview
Problem
Polar codes, particularly at short lengths, exhibit higher error floors and inferior error rate performance compared to other capacity-approaching codes like LDPC codes due to shorter minimum Hamming distance, and struggle with non-uniform reliability in communication channels.
Innovation Solution
The introduction of irregular polar codes with adaptive parameters such as irregular coupling values, permutation, and de-activated polarization operations, along with BCH concatenation and hard-decision cleaning, enhances error correction performance and reduces computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If short-length high-rate polar codes are used as constituent codes in spatially coupled polar codes, then the coding rate is improved, but the minimum Hamming distance decreases leading to higher error floors
Solution Approach 1:
The patent combines polar codes with BCH codes to form a hybrid concatenated code structure. The polar code component provides high coding rate and capacity-approaching performance, while the BCH code component provides strong error correction capability with guaranteed minimum Hamming distance. This composite approach allows the system to achieve both high productivity (coding rate) and high reliability (error rate performance) by leveraging the complementary strengths of both code types.
2Reliability
If regular polar coding construction is used, then theoretical capacity achievement is ensured, but adaptability to non-uniform channel reliability is poor
Solution Approach 1:
The patent introduces irregular polar codes that dynamically adjust the polarization process by selectively deactivating certain polarization operations based on channel conditions. This dynamic approach allows the code to adapt to non-uniform channel reliability patterns while maintaining the fundamental polarization mechanism that ensures capacity achievement. The irregular construction modifies the regular polar code structure to better match practical channel characteristics.
Solution Approach 2:
The patent changes key parameters of the polar code construction, including the polarization kernel selection and the activation/deactivation of polarization stages, to optimize performance for non-uniform channels. By adjusting these parameters, the code maintains its capacity-approaching properties while becoming adaptable to various channel conditions, including frequency-selective fading and time-varying channels.
3Reliability
If more iterations are performed in SD iterative decoding, then error correction performance is improved, but decoding latency and computational complexity increase
Solution Approach 1:
The patent incorporates BCH hard decision cleaning as a preliminary or intermediate step in the decoding process. The BCH decoder quickly identifies and corrects dominant error patterns before the soft decision iterative decoding continues. This preliminary action reduces the number of iterations needed by the SD decoder to achieve the same error correction performance, thereby reducing decoding latency and computational complexity while maintaining high reliability.
Data Source
AI summary
An encoder for encoding source information into an encoded codeword used in a communication channel includes a data input to receive source data, a processor, and a memory to store an encoder program. The encoder program makes the processor to encode the source data into a turbo product coding (TPC) structure, and the TPC structure comprises a data block corresponding to the source data, a first parity block including a first column part, a first corner part and a first bottom part, the first parity block being arranged so as to cover a right end column of the data block, a right bottom corner of the data block and a bottom row of the data block by the first column part, the first corner part and the first bottom part, and a second parity block having a row parity block, a joint parity block and a column parity block.