Mixed RF/FSO two-way relaying system under generalized FSO channel with pointing error

This paper investigates performance of a mixed radio frequency (RF)/free space optical (FSO) two-way relaying system. A half-duplex two-way relay is adopted to establish the communication between both RF and FSO links. Under this scenario, the associated end-to-end statistical features of the system are derived. They are then used for calculating outage and average symbol error rate (ASER) of M-ary phase shift keying (MPSK). Furthermore, we characterize the asymptotic behaviors and diversity orders for both outage and ASER at high signal-to-noise ratio (SNR). It is observed that the diversity orders depend on the severity of PE, which equals to 1/2 for weak PE and equals to g2/2 under strong PE with g being the PE severity. Finally, simulation results confirm the accuracy of the theoretical analysis and observations.