Arithmetic-Coded MCDM for Low Rate-Loss Constellation Shaping
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Solution Overview
Problem
Current constellation shaping techniques, such as constant composition distribution matchers (CCDM), face challenges in achieving efficient channel capacity utilization, especially for short-length packet transmissions due to their reliance on a single composition, leading to high rate loss.
Innovation Solution
The implementation of arithmetic coding-based multiple composition distribution matchers (MCDM) for wireless communication systems, which select a composition from a plurality based on a sequence of bits or symbols to achieve a desired modulation symbol distribution, enabling non-uniform distribution of constellation symbols and improving channel capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If constant composition distribution matcher (CCDM) with single composition is used, then device complexity is reduced, but rate loss increases and channel capacity utilization deteriorates
Solution Approach 1:
The patent segments the distribution matching process by dividing the set of modulation symbols into multiple compositions, where each composition represents a different distribution pattern. Instead of using a single composition as in CCDM, the system now uses multiple compositions (e.g., first composition, second composition, third composition) that can be selectively applied based on the data characteristics, thereby reducing rate loss while maintaining manageable complexity through structured organization
Solution Approach 2:
The patent introduces dynamic composition selection where the system adaptively chooses which composition to use based on the input data characteristics and transmission conditions. This dynamic approach allows the distribution matcher to optimize performance for different scenarios rather than being constrained to a fixed single composition, thereby improving channel capacity utilization without requiring excessive complexity
2Productivity
If multiple compositions are used in distribution matcher, then channel capacity utilization improves, but computational complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the cumulative probability distributions for each composition before actual transmission occurs. The system prepares multiple composition tables with their respective probability distributions in advance, so that during real-time operation, the encoder can quickly select and apply the appropriate composition without performing complex calculations from scratch, thus improving channel capacity utilization while controlling computational complexity
Solution Approach 2:
The patent utilizes parameter changes by varying the composition selection based on different transmission parameters such as code rate, modulation order, and channel conditions. The system changes which composition is active depending on these parameters, allowing optimization of channel capacity utilization for different scenarios without requiring the system to handle all possible compositions simultaneously, thereby managing computational complexity effectively
3Productivity
If arithmetic coding-based MCDM is implemented, then transmission efficiency improves, but implementation complexity increases
Solution Approach 1:
The patent introduces an intermediary composition selection mechanism that acts as a mediator between the input data and the arithmetic coding process. Before applying arithmetic coding, the system first selects the appropriate composition based on data characteristics, and this intermediate selection step simplifies the subsequent coding process by ensuring that the arithmetic coder operates on data with known distribution characteristics, thereby improving transmission efficiency while managing encoding complexity through this intermediary layer
Data Source
AI summary
Wireless communications systems and methods related to an efficient arithmetic coding based multiple composition distribution matcher (MCDM) are provided. A wireless communication device selects, based on a first value representing a sequence of bits, a first composition from a plurality of compositions. Each composition of the plurality of compositions includes a different modulation symbol distribution associated with a modulation scheme. The wireless communication device encodes, based on the first composition, the sequence of bits into a sequence of symbols using arithmetic coding. The wireless communication device transmits a communication signal including the sequence of symbols.