Multicarrier Symbol Mapping for Frequency-Diverse Decoding
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Solution Overview
Problem
In multicarrier operations, related bits in encoded data can become biased to specific carriers, leading to deteriorated decoding performance and error correction capabilities due to insufficient frequency diversity.
Innovation Solution
A radio communication device and method that employs symbol grouping, cyclic shifting, and group substitution to distribute modulated symbol blocks across multiple carriers, ensuring that related bits are dispersed across different carriers, thereby enhancing frequency diversity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If data segmentation and carrier mapping are performed without cyclic shifting, then the device complexity is reduced, but related bits become biased to specific carriers leading to deteriorated decoding performance
Solution Approach 1:
The modulation symbol sequence is segmented into multiple blocks through symbol grouping and group substitution, distributing related bits across different carrier blocks. This segmentation prevents bit biasing to specific carriers while maintaining manageable processing complexity through structured division of the data stream.
Solution Approach 2:
Cyclic shifting is applied to groups of modulation symbols before carrier mapping occurs. This preliminary action redistributes related bits across different carriers in advance, ensuring frequency diversity is achieved before the data is mapped to physical resources, thereby improving decoding performance without adding complex real-time processing requirements.
2Reliability
If simple data segmentation is performed without symbol grouping and cyclic shifting, then the processing complexity is reduced, but frequency diversity is insufficient causing related bits to be concentrated on specific carriers
Solution Approach 1:
The modulation symbol sequence is divided into J parts based on FEC block structure, with each part further segmented into N groups. This multi-level segmentation ensures related bits are distributed across different carrier blocks while maintaining a systematic processing structure that manages complexity through organized division rather than random distribution.
Solution Approach 2:
Different cyclic shift amounts are applied to different groups within the modulation symbol sequence. This asymmetric treatment of groups ensures that related bits are dispersed across carriers in a controlled manner, creating frequency diversity without requiring symmetric or uniform processing that would be less effective at bit distribution.
3Reliability
If related bits are mapped to the same carrier block, then the mapping process is simplified, but error correction capability deteriorates due to lack of frequency diversity
Solution Approach 1:
Cyclic shifting is performed on groups of modulation symbols before the carrier mapping step. This preliminary redistribution of bits ensures that when mapping occurs, related bits are already dispersed across different carrier blocks, achieving frequency diversity without complicating the mapping process itself. The complexity is handled in the preprocessing stage rather than during mapping.
Solution Approach 2:
The modulation symbol sequence is segmented into multiple blocks with structured grouping, ensuring that related bits are distributed across different carrier blocks. This segmentation approach maintains a systematic and organized mapping process while achieving the bit dispersion necessary for error correction capability.
Data Source
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AI summary
To improve the frequency diversity effect by preventing the related bits in the encoded data from being biased to the specified carrier in the case of performing the multicarrier operation. A modulated symbol sequence is segmented in a data segmentation section (116), and the segmented modulated symbol blocks are mapped on a plurality of carriers in a segment mapping section (120). The data segmentation section (116) groups each of K parts in the modulated symbol sequence into the same number of N groups, cyclically shifts the N groups for the respective parts of any (K-1) parts with shift amounts which differ among the parts, and substitutes the cyclically-shifted groups of the plurality of parts in the modulated symbol sequence with one another among the parts to segment the groups into a plurality of blocks.