LDPC Decoding with Child Parity Matrix for Punctured Codewords
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Solution Overview
Problem
The decoding of punctured Low Density Parity Check (LDPC) codewords in communication systems experiences increased calculations and decreased decoding convergence speed due to the puncturing scheme, which affects the performance of variable coding rate support in next-generation mobile communication systems.
Innovation Solution
A decoding apparatus and method that determines whether an LDPC codeword is punctured or not, and generates a child parity check matrix based on a mother parity check matrix and puncturing pattern to decode the punctured codeword, effectively reducing calculations and improving convergence speed by removing punctured parity nodes from the Tanner graph.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the puncturing scheme is applied to support variable coding rates, then coding rate flexibility is improved, but the decoding convergence speed deteriorates
Solution Approach 1:
The parity check matrix is segmented into information word parity check matrix and parity bit parity check matrix. The puncturing operation is applied selectively to the parity bit portion, allowing the information word portion to maintain normal decoding convergence while the punctured parity bits provide coding rate flexibility.
Solution Approach 2:
The punctured parity bits are extracted and removed from the transmitted codeword. At the receiver, only the non-punctured parity bits are used for decoding, effectively taking out the harmful punctured nodes from the decoding process while preserving coding rate adaptability.
2Adaptability or versatility
If the puncturing scheme is applied to increase coding rate, then coding rate is improved, but the number of calculations increases
Solution Approach 1:
The parity check matrix is divided into information word parity check matrix and parity bit parity check matrix. This segmentation allows the decoder to process only the necessary non-punctured parity bits, reducing the computational burden while maintaining support for variable coding rates.
Solution Approach 2:
Instead of processing all parity bits including punctured ones, the decoder performs partial action by processing only the non-punctured parity bits. This reduces the number of calculations required while still achieving the desired coding rate flexibility.
3Adaptability or versatility
If punctured parity nodes are included in the Tanner graph, then puncturing scheme functionality is maintained, but decoding performance deteriorates
Solution Approach 1:
The punctured parity nodes are extracted and removed from the Tanner graph used for decoding. This eliminates the harmful effect of punctured nodes transmitting constant '0' values, thereby improving decoding performance while the puncturing scheme functionality is maintained through selective use of non-punctured parity bits.
Solution Approach 2:
The puncturing operation, which initially creates harmful nodes in the Tanner graph, is converted into a benefit by selectively excluding only the punctured parity bits from decoding. This transforms the potential harm into a useful mechanism for achieving variable coding rates without degrading performance.
Data Source
AI summary
A decoding method in a communication system using a Low Density Parity Check (LDPC) code. The method includes determining whether an LDPC codeword to be decoded is a general LDPC codeword to which a puncturing scheme is not applied or a punctured LDPC codeword to which the puncturing scheme is applied; if the LDPC codeword to be decoded is the punctured LDPC codeword, generating a child parity check matrix according to a mother parity check matrix indicative of a parity check matrix of the general LDPC codeword, and a puncturing pattern applied to the punctured LDPC codeword; and decoding the punctured LDPC codeword according to the child parity check matrix.