SNR-Adaptive Non-Uniform Constellation Mapping for BICM Throughput
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Solution Overview
Problem
Current coding and modulation systems, particularly in BICM apparatuses, face limitations in maximizing coding and modulation capacity due to regular constellation grids and inadequate adaptation to channel characteristics like AWGN and fading.
Innovation Solution
A coding and modulation apparatus that uses a non-uniform constellation with optimized constellation points based on signal-to-noise ratio (SNR) and channel characteristics, defined by constellation position vectors, to enhance coding and modulation capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If regular constellation grids are used in BICM apparatuses, then device complexity is reduced and ease of operation is improved, but coding and modulation capacity cannot be maximized and adaptation to channel characteristics is inadequate
Solution Approach 1:
The patent applies local quality by assigning different spatial characteristics to different regions of the constellation diagram. Specifically, constellation points are positioned at different distances from the origin based on their assigned bits, creating non-uniform spatial distribution that adapts to channel characteristics like AWGN and fading, thereby improving adaptability without requiring complex dynamic reconfiguration
Solution Approach 2:
The patent changes the spatial parameter (distance from origin) of constellation points based on channel conditions and signal-to-noise ratio. By optimizing the positions of constellation points in the complex plane, the system adapts to varying channel characteristics while maintaining a fixed constellation structure, resolving the contradiction between adaptability and complexity
2Productivity
If non-uniform constellation with optimized points is used, then coding and modulation capacity is increased, but constellation design and selection complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-optimizing constellation point positions for different signal-to-noise ratio conditions and channel characteristics before actual transmission. The modulator is pre-configured with multiple non-uniform constellation definitions, each optimized for specific conditions, allowing the system to achieve high coding capacity without real-time optimization complexity
Solution Approach 2:
The patent introduces dynamics by enabling the modulator to dynamically select among multiple pre-defined non-uniform constellation configurations based on current channel conditions and signal-to-noise ratio. This dynamic selection allows the system to adapt to varying conditions and maximize coding capacity without the complexity of real-time constellation optimization
Data Source
AI summary
A coding and modulation apparatus and method are presented. The apparatus (10) comprises an encoder (11) that encodes input data into cell words, and a modulator (12) that modulates said cell words into constellation values of a non-uniform constellation. The modulator (12) is configured to use, based on the total number M of constellation points of the constellation and the signal-to-noise ratio SNR in dB, a non-uniform constellation from a group of constellations comprising one or more of predetermined constellations defined by the constellation position vector w0 . . . b−1, wherein b=M/4.