Performance Analysis of Two-Way Relay in Free Space Optics Systems

The purpose of this research is to evaluate the effectiveness of Two-Way Relay (TWR) aided Free Space Optics (FSO) systems in a variety of atmospheric conditions, such as route loss, aiming errors, and atmospheric turbulence. In order to illustrate the effects of varying levels of turbulence, ranging from mild to severe, several statistical models are employed, such as log-normal and Gamma-Gamma, to represent the fading caused by air turbulence. There is a remarkable degree of congruence between the theoretical evidence and the experimental data in these models. For the system and channel models that have been provided, the statistical features of the instantaneous signal-to-noise ratio (SNR) are computed. Furthermore, the evaluation of error performance involves the computation of the mean Symbol Error Rate (SER) for M-PSK modulation. Bi-directional cooperative relaying schemes have demonstrated their ability to enhance the spectral efficiency of FSO networks connecting two users. TWR is expanded in a multiple user FSO system by implementing several multiuser scheduling techniques at the TWR to choose a single user-pair. The TWR facilitates a two-way communication connection between the designated pair of users. An optical channel is considered that experiences fading due to aiming errors and air turbulence, modelled using the M-distribution. For the system and scheduling approaches that have been given, closed form methods are utilized in order to compute the outage probability and bit error rate (BER). The expressions are formed using Meijer's G-function, which provides succinct and easily calculable formulas. In addition, the discussion includes asymptotic expressions to gain a deeper understanding of the analytical conclusions that have been produced.