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Optimization of three-dimensional superposed constellation with probabilistic shaping for MIMO visible light
Optics Express
|November 14, 2024
Summary
This study introduces a novel superposed 3D-32QAM constellation for visible-light communication (VLC) systems. The new method enhances data transmission robustness and reduces LED distortion in MIMO channels.
Area of Science:
- Optical Communications
- Digital Signal Processing
Background:
- Visible-light communication (VLC) systems utilize light for data transmission.
- Multiple-input multiple-output (MIMO) channels in VLC are prone to signal correlation.
- Superposed constellation technology offers robustness against channel correlation.
Purpose of the Study:
- To propose a novel superposed three-dimensional 32-quadrature amplitude modulation (3D-32QAM) constellation scheme for MIMO VLC systems.
- To combine superposed 3D constellations with probabilistic shaping to enhance performance.
- To improve the minimum Euclidean distance (MED) and mitigate nonlinear distortion.
Main Methods:
- Transmitting tetrahedron-shaped 3D-4QAM and cube-shaped 3D-8QAM signals from separate LEDs.
- Superposing these signals at the receiver to create a cross-shaped 32QAM signal.
- Implementing global and local probabilistic shaping through 3D constellation superposition.
Main Results:
- The proposed 3D-32QAM scheme improved the minimum Euclidean distance (MED).
- Probabilistic shaping reduced the risk of nonlinear distortion from light-emitting diodes (LEDs).
- Achieved better normalized generalized mutual information (NGMI) performance.
Conclusions:
- The novel superposed 3D-32QAM constellation scheme enhances MIMO VLC systems.
- The scheme offers improved NGMI and a wider dynamic voltage range compared to 2D schemes.
- Probabilistic shaping of superposed 3D constellations is effective for VLC.
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