LDPC Block Interleaving for High-Order Modulation Reliability
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Solution Overview
Problem
In communication and broadcasting systems, existing methods fail to effectively address noise, fading, and inter-symbol interference, particularly in high data throughput applications like next-generation mobile communication and digital broadcasting, due to limitations in error-correction codes and modulation schemes.
Innovation Solution
A transmitting apparatus and method that employs a Low Density Parity Check (LDPC) code encoder, interleaver, and modulator to map LDPC codeword bits onto modulation symbols using a block interleaver with specific row configurations based on modulation methods, enhancing encoding and reception performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LDPC encoding is used to overcome noise and fading, then reliability is improved, but device complexity increases
Solution Approach 1:
The LDPC codeword is divided into multiple bit groups, and the interleaver is configured with multiple columns that process different bit groups separately. This segmentation allows the complex LDPC encoding to be broken down into manageable parts that can be processed independently, reducing the overall computational burden while maintaining reliability benefits
Solution Approach 2:
The interleaver configuration is made dynamic by adjusting the number of rows in each column based on the modulation method being used. This allows the system to adapt the encoding/interleaving complexity to match the current communication conditions, optimizing the balance between reliability and device complexity
2Productivity
If high order modulation is used to increase data throughput, then productivity is improved, but measurement precision deteriorates due to noise sensitivity
Solution Approach 1:
Different columns in the interleaver are assigned different numbers of rows based on the modulation method, creating local variations in the interleaving pattern. This allows specific bit groups to be mapped with different levels of protection against noise, with more critical bits receiving enhanced protection while maintaining high overall throughput
Solution Approach 2:
The system changes the interleaver structure parameters (number of rows per column) based on the modulation method being used. For high-order modulations that are more noise-sensitive, the interleaver configuration is adjusted to provide better error protection, thereby maintaining measurement precision while preserving productivity benefits
3Reliability
If iterative decoding is applied to achieve channel capacity performance, then reliability is improved, but loss of time increases due to multiple decoding iterations
Solution Approach 1:
The interleaving operation is performed in advance before modulation, organizing the LDPC codeword bits into a structure that is optimized for iterative decoding. This preliminary arrangement of bits across multiple columns with varying row counts facilitates more efficient convergence during decoding iterations, reducing the time required to achieve reliable decoding
Data Source
AI summary
A transmitting apparatus and a receiving apparatus are provided. The transmitting apparatus includes: an encoder configured to generate a low density parity check (LDPC) codeword by performing LDPC encoding; an interleaver configured to interleave the LDPC codeword; and a modulator configured to modulate the interleaved LDPC codeword according to a modulation method to generate a modulation symbol. The interleaver is formed of a plurality of columns each including a plurality of rows and includes a block interleaver configured to divide each of the plurality of columns into a first part and a second part and interleave the LDPC codeword, the number of rows constituting each column divided into the first part is determined differently depending upon the modulation method, wherein the number of rows constituting each column divided into the second part is determined depending upon the number of rows constituting each column divided into the first part.