LDPC Mapper Patterns for DVB-NGH Shaping Gain
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Solution Overview
Problem
The DVB-NGH system faces challenges in obtaining maximum shaping gain due to the direct adaptation of non-uniform mapping patterns from the DVB-T2 system, particularly with the 64 k mode, L1 signaling information, and MIMO profiles, which results in suboptimal error correction capabilities and increased C/N ratios.
Innovation Solution
A transmission device and method that selectively maps error correction coded frames in non-uniform patterns based on predetermined bit lengths, even when coding rates are identical, allowing for efficient shaping gain optimization by defining distinct non-uniform mapping patterns for different LDPC code lengths and transmission systems like SISO, MISO, and MIMO.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If non-uniform mapping patterns from DVB-T2 system are directly adapted to DVB-NGH system, then implementation simplicity is improved, but shaping gain and error correction capability deteriorate
Solution Approach 1:
The patent applies local quality by defining different non-uniform mapping patterns tailored to specific DVB-NGH transmission scenarios (64k mode, L1 signaling information, MIMO profiles) rather than using a universal mapping pattern from DVB-T2. Each scenario receives optimized mapping characteristics appropriate to its specific requirements, achieving both implementation feasibility and improved error correction capability.
Solution Approach 2:
The patent changes the mapping pattern parameters by defining new non-uniform mapping patterns with specific constellation arrangements optimized for DVB-NGH requirements. These parameter changes include adjusting the distribution of signal points in the constellation diagram to achieve maximum shaping gain, thereby improving error correction capability while maintaining implementation simplicity.
2Device complexity
If identical coding rates use the same non-uniform mapping pattern, then system complexity is reduced, but shaping gain optimization is limited
Solution Approach 1:
The patent implements local quality by associating different non-uniform mapping patterns with different code lengths (16k, 64k modes) even when coding rates are identical. This allows each code length to have optimized mapping characteristics, achieving maximum shaping gain for each specific scenario while maintaining manageable system complexity through structured pattern selection.
3Ease of manufacture
If uniform mapping pattern is used across all code lengths, then implementation is simplified, but frequency use efficiency and transmission performance deteriorate
Solution Approach 1:
The patent changes the mapping pattern parameters by defining non-uniform mapping patterns with optimized constellation arrangements for different code lengths. This allows the system to achieve maximum shaping gain and improved frequency use efficiency while maintaining implementation simplicity through the structured approach of selecting from predefined patterns.
Data Source
AI summary
An FEC coder in a transmission device according to an exemplary embodiment of the present disclosure performs BCH coding and LDPC coding based on whether a code length of the LDPC coding is a 16 k mode or a 64 k mode. A mapper performs mapping in an I-Q coordinate to perform conversion into an FEC block, and outputs pieces of mapping data (cells). The mapper defines different non-uniform mapping patterns with respect to different code lengths even an identical coding rate is used by the FEC coder. This configuration improves a shaping gain for different error correction code lengths in a transmission technology in which modulation of the non-uniform mapping pattern is used.