M-ary pulse position modulation performance in strong atmospheric turbulence.

Area of Science:

• Optical Wireless Communications
• Atmospheric Turbulence
• Signal Processing

Background:

• Optical wireless communication systems face performance degradation due to atmospheric turbulence.
• M-ary pulse position modulation (PPM) is a technique used in these systems.
• Accurate performance evaluation requires considering scintillation effects.

Purpose of the Study:

• To investigate the performance of M-ary PPM optical wireless communication systems in strong atmospheric turbulence.
• To quantify the impact of scintillation on the bit error rate (BER).
• To analyze the influence of various system parameters on BER.

Main Methods:

• Utilized the extended Huygens-Fresnel principle to model average received power at a finite-sized avalanche photodiode (APD) detector.
• Employed asymptotic Rytov theory and gamma-gamma intensity statistics for aperture-averaged scintillation evaluation.
• Calculated the scintillation index using log-intensity variances for both weak and strong turbulence regimes.

Main Results:

• Examined bit error rate (BER) variations against the plane wave scintillation index.
• Analyzed the effects of receiver aperture diameter, data bit rate, M-ary PPM values, quantum efficiency, and average APD gain on BER.
• Demonstrated the relationship between scintillation index and system performance under different operating conditions.

Conclusions:

• The study provides a comprehensive performance analysis of M-ary PPM systems in turbulent environments.
• Findings highlight the critical role of scintillation and system parameters in determining communication reliability.
• The developed model and analysis are valuable for designing robust optical wireless communication systems.