Capacity analysis for pulse amplitude modulated visible light communications with dimming control

Area of Science:

• Optical Communications
• Signal Processing
• Information Theory

Background:

• Visible light communication (VLC) systems utilize pulse amplitude modulation (PAM).
• Achieving channel capacity in PAM-VLC is challenging under practical constraints like non-negativity and power limitations.
• Existing methods lack analytical expressions for optimal input distributions.

Purpose of the Study:

• To develop a capacity-approaching, nonuniform input distribution for PAM-VLC.
• To provide a computationally simple method for deriving this distribution.
• To guide practical system design in PAM-VLC.

Main Methods:

• Characterizing the input distribution by three parameters: intensities, probabilities, and number of mass points.
• Deriving a computationally simple, capacity-approaching input distribution.
• Evaluating performance through numerical simulations.

Main Results:

• A novel, capacity-approaching input distribution for PAM-VLC was derived.
• The derived distribution is computationally efficient and practical for system design.
• Numerical results show superior performance compared to uniform input distributions.

Conclusions:

• The proposed nonuniform signaling approach effectively approaches channel capacity in PAM-VLC.
• This method offers a practical tool for enhancing PAM-VLC system performance.
• The derived distribution provides a significant performance gain over conventional uniform distributions.