Constellation symbol OAM encoding for an atmospheric turbulence-resistant optical transmission method based on...

Area of Science:

• Optical Communications
• Information Theory
• Signal Processing

Background:

• Vortex beams carrying orbital angular momentum (OAM) are crucial for increasing free-space optical communication capacity.
• Atmospheric turbulence significantly degrades the transmission quality of OAM vortex beams, posing a major challenge.

Purpose of the Study:

• To propose and validate an anti-turbulence method for OAM vortex beams using trellis-coded modulation.
• To enhance the robustness and reliability of free-space optical communication systems operating under turbulent conditions.

Main Methods:

• Source information is error-correction coded and modulated into constellation symbols.
• Orbital angular momentum (OAM) coding is applied to these constellation symbols.
• A convolutional neural network is employed for detecting the OAM-coded constellation symbols.

Main Results:

• The proposed trellis-coded modulation scheme demonstrates superior bit error rate (BER) performance compared to traditional methods under various turbulence intensities.
• The technique provides more stable turbulence suppression across different transmission distances.
• Increasing the number of samples significantly improves BER performance, highlighting the method's scalability.

Conclusions:

• The developed anti-turbulence method effectively mitigates the impact of atmospheric turbulence on OAM vortex beams.
• This coding-based approach offers a valuable reference for future research on improving the anti-turbulence capabilities of vortex beams in optical communication.