Amplify-and-Forward Two-Way Relaying System over Free-Space Optics Channels

Abstract

In this paper, we analyze the performance of a two-waysubcarrier intensity-modulated (SIM) amplify-and-forward (AF)relaying system over free-space optics (FSO) communication channels. The analysis takes into consideration attenuations due to atmosphericturbulence, geometric spread and pointing errors at thesame time. We derive, in generalized infinite power series expressions,the tight upper and lower bounds of the overall outage probabilityand average probability of errors of the system. The studyfinds that this two-way subcarrier intensity-modulated AF relayingsystem using a binary phase shift keying (BPSK) modulationcould be used for practical applications in case of a weak turbulenceregime in which the required SNR is about 30 dB to obtainthe average bit error probability of 10􀀀6. It is also noted that thepointing errors clearly degrade the performance of the two-waysubcarrier intensity-modulated AF relaying system.