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Receiver design for SPAD-based VLC systems under Poisson-Gaussian mixed noise model
Optics Express
|February 4, 2017
Summary
This study introduces a new detector for visible light communication systems using single-photon avalanche diodes (SPADs). It addresses mixed noise, improving signal detection accuracy in low light.
Area of Science:
- Optical Communications
- Signal Processing
- Photonics
Background:
- Single-photon avalanche diodes (SPADs) offer high sensitivity for visible light communications (VLC).
- Existing VLC channel models often oversimplify noise, neglecting Gaussian thermal noise from receiver components like TIA and D/A converters.
- Accurate noise modeling is crucial for reliable SPAD-based VLC systems.
Purpose of the Study:
- To propose a novel SPAD-based VLC system utilizing pulse-amplitude modulation (PAM) under a more realistic Poisson-Gaussian mixed noise model.
- To develop advanced detection algorithms that account for both Poisson and Gaussian noise sources.
- To enhance the performance and efficiency of SPAD detectors in VLC applications.
Main Methods:
- Derivation of the closed-form conditional likelihood of received signals using Laplace transform and saddle-point approximation.
- Proposal of a quasi-maximum-likelihood (quasi-ML) detector.
- Application of the generalized Anscombe transform (GAT) to convert Poisson-Gaussian signals to Gaussian variables, enabling an equivalent additive white Gaussian noise (AWGN) channel.
- Implementation of a hard-decision-based detector using GAT.
Main Results:
- A quasi-ML detector was developed for the proposed Poisson-Gaussian noise model.
- The GAT effectively transforms the mixed noise channel into an equivalent AWGN channel.
- The GAT-based detector achieves reduced computational complexity with minimal performance degradation compared to the quasi-ML detector.
- Both proposed detectors demonstrate accurate demodulation of SPAD-based PAM signals.
Conclusions:
- The proposed Poisson-Gaussian mixed noise model provides a more accurate representation for SPAD-based VLC systems.
- The GAT-based detector offers a practical solution with lower computational load and comparable performance to the quasi-ML detector.
- These advancements contribute to the improved reliability and efficiency of future SPAD-based VLC systems, especially in low-light conditions.
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