LDPC Interleaving and Bit Mapping for Robust Broadcast Transmission
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Solution Overview
Problem
There is a need for improved methods to support digital broadcasting services with robust encoding, decoding, and receiving performance, particularly in the context of digital televisions and portable multimedia players, where existing technologies may not adequately meet the demands for high-quality, multi-channel, and wideband broadcasting.
Innovation Solution
A transmitting apparatus and interleaving method that utilize an LDPC codeword encoder, interleaver, and modulator to map and transmit bits, specifically using a parity check matrix to generate and interleave LDPC codewords, ensuring improved decoding and receiving performance through efficient bit grouping and modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional encoding and modulation methods are used, then device complexity is reduced, but decoding and receiving performance deteriorates
Solution Approach 1:
The interleaver is divided into multiple sub-interleavers (first sub-interleaver, second sub-interleaver, third sub-interleaver) that process different portions of the codeword separately. This segmentation allows complex interleaving to be achieved through simpler, modular components, improving decoding performance while managing device complexity through structured division of functions.
Solution Approach 2:
The patent employs nested interleaving structures where sub-interleavers are contained within a main interleaver framework. The first sub-interleaver processes bits within groups, the second sub-interleaver processes groups, and the third sub-interleaver performs final ordering - creating a nested hierarchy that achieves robust interleaving through layered, manageable stages.
2Reliability
If simple modulation mapping is used, then device complexity is reduced, but receiving performance deteriorates
Solution Approach 1:
Different bit groups within the codeword are mapped to different bit positions within modulation symbols based on their specific characteristics and error protection requirements. The patent applies distinct mapping strategies for information bits versus parity bits, and for different positions within the codeword, optimizing receiving performance for each local context rather than using uniform mapping.
Solution Approach 2:
The interleaving process is performed before modulation mapping, pre-arranging bits in optimal sequences that anticipate channel conditions and error patterns. This preliminary ordering of bits through multiple sub-interleavers ensures that when mapping occurs, the bits are already positioned to maximize receiving performance under expected transmission conditions.
Data Source
AI summary
A transmitting apparatus is provided. The transmitting apparatus includes: an encoder configured to generate a Low Density Parity Check (LDPC) codeword by LDPC encoding based on a parity check matrix; an interleaver configured to interleave the LDPC codeword; and a modulator configured to map the interleaved LDPC codeword onto a plurality of modulation symbols, wherein the modulator is configured to map bits included in a predetermined bit group from among a plurality of bit groups constituting the LDPC codeword onto a predetermined bit of each of the modulation symbols.