A Comprehensive Model for Performance Analysis of APD-based FSO Systems using M-PPM Signaling in Atmospheric Turbulence

Abstract

In this paper, a model of Gaussian pulse propagation over atmospheric turbulence channel is used to comprehensively analyze the performance of APD-based free-space optical communication (FSO) systems using M-PPM signaling. This model is able to simultaneously take into account all effects of atmospheric turbulence including attenuation, intensity fluctuation, and pulse broadening, which has not been considered in previous works. In addition, the impacts of APD shot noise, background noise, and thermal noise are included in our analysis. The numerical results show that the main factor that limits the system performance is intensity fluctuation. However, when M is large enough, optical pulse is so short that the effect of pulse broadening becomes dominant. By using APD receiver, bit-error rate is improved significantly. Finally, based on channel capacity, we are able to determine the maximum transmission length of the system.