LDPC Bit Interleaving for 1024-QAM Broadcast Transmission
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Solution Overview
Problem
Current digital broadcasting systems face challenges in providing robust encoding, decoding, and receiving performance for high-quality digital services, particularly with the increasing demand for multi-channel and wideband broadcasting.
Innovation Solution
A transmitting apparatus and method that employs Low Density Parity Check (LDPC) coding, including an encoder for generating LDPC codewords, an interleaver for rearranging bit groups, and a modulator to map bits onto modulation symbols, utilizing a parity check matrix to enhance decoding and receiving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional encoding methods are used in digital broadcasting systems, then the system structure remains simple, but decoding and receiving performance deteriorates under high-quality digital service demands
Solution Approach 1:
The LDPC codeword is divided into multiple bit groups, and each bit group is further divided into sub-bit groups. This segmentation allows for granular interleaving operations where bits within each sub-bit group are permuted independently, improving decoding performance by distributing burst errors while maintaining a manageable encoding structure.
Solution Approach 2:
The patent introduces a two-dimensional interleaving structure by first dividing the codeword into bit groups and then subdividing into sub-bit groups with specific intra-group permutations. This multi-level grouping approach adds dimensional complexity to the encoding process, enabling better error distribution across multiple dimensions of the transmission channel.
2Reliability
If bit-level interleaving is applied to improve decoding performance, then receiving robustness improves, but processing complexity increases
Solution Approach 1:
The interleaving process is segmented into multiple stages: first dividing the LDPC codeword into bit groups, then subdividing each bit group into sub-bit groups, and finally applying permutation within each sub-bit group. This hierarchical segmentation reduces processing complexity by breaking down a single complex interleaving operation into multiple simpler, independent operations.
Solution Approach 2:
Different permutation patterns are applied to different sub-bit groups based on their specific positions and characteristics. Each sub-bit group undergoes localized interleaving tailored to its context, which improves receiving robustness for specific error patterns while keeping the overall processing complexity manageable through localized rather than global transformations.
Data Source
AI summary
Provided is a signal interleaving method which includes: interleaving parity bits by encoding input bits based on a low density parity check (LDPC) code according to a code rate of 6/15 and a code length of 64800; splitting a codeword comprising the input bits and the interleaved parity bits into a plurality of bit groups; interleaving the plurality of bit groups according to a specific permutation order to provide an interleaved codeword; de-multiplexing bits of the interleaved codeword to generate data cells; mapping the data cells onto constellation points for 1024-quadrature amplitude modulation (QAM); and transmitting a signal based on the constellation points.