Symbol error rate of soft-decision multiple pulse position modulation over turbulent channels

Area of Science:

• Optical Communications
• Signal Processing

Background:

• Soft-decision multiple-pulse-position modulation (MPPM) is a key modulation technique in free-space optical communications.
• Accurate performance evaluation under fading is crucial for reliable optical links.

Purpose of the Study:

• To derive theoretical symbol error rate (SER) expressions for soft-decision MPPM.
• To analyze performance under fast and slow fading conditions without receiver channel state information.
• To validate these expressions using lognormal and gamma-gamma turbulence models.

Main Methods:

• Derivation of theoretical SER expressions for non-memoryless channel conditions.
• Application to soft-decision MPPM without channel state information.
• Simulation-based verification using lognormal and gamma-gamma turbulence models.

Main Results:

• Theoretical SER expressions were successfully derived for soft-decision MPPM under both fast and slow fading.
• The derived expressions accurately predicted performance when validated against simulations.
• The study confirmed the applicability of the models to turbulence-affected optical channels.

Conclusions:

• The developed theoretical framework provides accurate SER predictions for soft-decision MPPM in fading optical channels.
• This work is valuable for designing robust free-space optical communication systems.
• The findings support the use of MPPM in scenarios with unknown channel state information.