Dual threshold demodulation algorithm for ultraviolet optical communication under turbulent channels

Area of Science:

• Optical Communications
• Atmospheric Turbulence
• Signal Processing

Background:

• Atmospheric turbulence causes severe scintillation, degrading optical irradiance in ultraviolet (UV) communication systems.
• Traditional demodulation algorithms suffer significant performance degradation, especially in moderate to strong turbulence channels.
• UV communication faces challenges with long distances and large elevation angles due to atmospheric effects.

Purpose of the Study:

• To propose a novel signal demodulation algorithm for UV communication systems experiencing severe scintillation.
• To address the performance degradation of existing algorithms in turbulent UV communication channels.
• To validate the algorithm's effectiveness in real-world kilometer-scale UV communication scenarios.

Main Methods:

• Development of a signal probability model based on UV turbulence characteristics.
• Derivation of an optimal solution using dual judgment thresholds.
• Experimental validation using a UV LED-based communication system over a 1000 m link.

Main Results:

• The proposed algorithm achieves a low bit error rate (BER) even in long-distance, large-elevation angle scenarios.
• Demonstrated significant improvement over traditional demodulation schemes in moderate and strong turbulence.
• Reduced BER by nearly four orders of magnitude compared to traditional algorithms in a 1000 m experimental setup.

Conclusions:

• The novel algorithm effectively mitigates the impact of atmospheric turbulence on UV communication.
• The proposed method significantly enhances the reliability and performance of UV communication systems.
• This research provides a robust solution for UV communication in challenging atmospheric conditions.