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Hybrid channel coding for OAM division multiplexing free space optical communication systems
Optics Express
|September 15, 2023
Summary
This study introduces hybrid channel coding for orbital angular momentum division multiplexing free space optical communication (OAM-DM FSO) systems. This method enhances coding gain by addressing atmospheric turbulence, improving overall system performance.
Area of Science:
- Optical Communications
- Information Theory
- Atmospheric Physics
Background:
- Free space optical communication (FSO) systems face performance degradation due to atmospheric turbulence.
- Orbital angular momentum (OAM) division multiplexing (DM) offers increased data capacity in FSO systems.
- Channel coding is crucial for mitigating fading and errors in FSO links.
Purpose of the Study:
- To propose and evaluate a hybrid channel coding scheme for OAM-DM FSO systems.
- To improve coding gain by accounting for mode-dependent channel fading caused by atmospheric turbulence.
- To enhance the overall performance and reliability of OAM-DM FSO communication.
Main Methods:
- Implementation of a hybrid channel coding strategy within an OAM-DM FSO system.
- Modeling of atmospheric turbulence effects, specifically mode-dependent channel fading.
- Simulation analysis comparing the proposed hybrid coding with single channel coding.
Main Results:
- The hybrid channel coding approach significantly increases coding gain compared to single channel coding.
- For an OAM1/OAM3 multiplexing system, a coding gain increase of 1.85 dB was observed (Cn2=1E-14, BER=1E-5) using a non-uniform LDPC code (0.7 code rate).
- For a four-OAM mode multiplexing system (+1,+3,+5,+7), the coding gain improvement exceeded 3.8 dB under similar atmospheric conditions (Cn2=1E-14, BER=1E-5).
Conclusions:
- Hybrid channel coding effectively compensates for atmospheric channel fading in OAM-DM FSO systems.
- The proposed method enhances coding gain by considering atmospheric turbulence-induced mode-dependent fading.
- This approach offers a viable solution for improving the performance and robustness of high-capacity FSO communication.
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